taxonID	type	description	language	source
26013B6042664F1E1FECFE034BBDFBE4.taxon	materials_examined	Material examined: None.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042664F1E1FECFE034BBDFBE4.taxon	description	Description: Anker et al. (2012).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042664F1E1FECFE034BBDFBE4.taxon	distribution	Distribution: Eastern Atlantic: São Tomé and Príncipe. Western Atlantic: Panama (Bocas del Toro), Dominican Republic (Bayahibe), Aruba and Brazil (Rocas Atoll) (Anker et al. 2012).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042664F1E1FECFE034BBDFBE4.taxon	biology_ecology	Ecology: In cavities of dead eroded corals and in coralline algae; in heterosexual pairs; up to 2 m (Anker et al. 2012).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042664F1E1FECFE034BBDFBE4.taxon	discussion	Remarks: The amphi-Atlantic S. africanus is morphologically very similar to S. tenuispina (Coutière, 1909) (see Anker et al. 2012). However, Anker et al. (2012) reported genetic differences between specimens from São Tomé and Príncipe (a male and an ovigerous female) and a typical S. africanus specimen from the eastern Atlantic. Additionally, the authors noted that materials from Rocas Atoll, Aruba, and Panama exhibit characteristics more consistent with S. africanus than S. tenuispina, particularly regarding the length of the scaphocerite and the shape of the rostrum (Anker et al. 2012). Specimens from these regions were also found to be significantly smaller than the type material of S. tenuispina. According to Anker et al. (2012), a more comprehensive study, encompassing both morphological and genetic analysis, must be conducted to address the taxonomic issues associated with these taxa.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042664F1E1FECFBBB4D3BF82B.taxon	materials_examined	Material examined: Pernambuco — Continental Shelf off Recife: 1 M, 27. ii. 2018, 8 ° 13 ′ 52.1 ′′ S 34 ° 37 ′ 39.1 ′′ W, 50.8 m depth, in sponge, DZ / UFRGS 7049; 1 M, same data as DZ / UFRGS 7049, in sponge, MOUFPE 21542; Fernando de Noronha: 2 M, 6 F, Ressureta, 19. vi. 2019, 03 ° 49.191 ′ S 32 ° 23.847 ′ W, 8.0 m depth, in sponge, DZ / UFRGS 6710; 2 M, 3 F, Cagarras, 25. vi. 2022, 03 ° 50.933 ′ S 32 ° 26.178 ′ W, 13.0 m depth, in sponge, DZ / UFRGS 7025; 1 M, 3 F, Ressureta, 25. vi. 2022, 03 ° 50.933 ′ S 32 ° 26.178 ′ W, 8.0 m depth, in sponge, DZ / UFRGS 7028; 3 M, 3 OV, 5 F, Buraco do Inferno, 26. vi. 2022, 03 ° 48.968 ′ S 32 ° 23.577 ′ W, 12.0 m depth, in sponge, DZ / UFRGS 7029; 10 M, 3 OV, 6 F, Ilha do Meio, 26. vi. 2022, 03 ° 49.015 ′ S 32 ° 23.549 ′ W, 11.0 m depth, in sponge, DZ / UFRGS 7035; 6 M, 4 OV, 2 F, Ponta da Sapata, 30. vi. 2022, 03 º 51.892 ′ S 32 º 27.965 ′ W, 11.0 m depth, in sponge, DZ / UFRGS 7040; 9 M, 4 OV, 1 F, Laje Dois Irmãos, 30. vi. 2022, 03 ° 51.859 ′ S 32 ° 27.934 ′ W, 17.0 m depth, in sponge, DZ / UFRGS 7044.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042664F1E1FECFBBB4D3BF82B.taxon	description	Description: Pequegnat & Heard (1979), Ríos & Duffy (2007), and Anker et al. (2012).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042664F1E1FECFBBB4D3BF82B.taxon	distribution	Distribution: Gulf of Mexico, Puerto Rico, Cuba, Belize, Jamaica, Panama, Curaçao, Barbados, and Brazil (Fernando de Noronha, Rocas Atoll, seamounts of North Chain, Trindade & Martin Vaz Archipelago, and from Amapá to Espírito Santo) (Coelho-Filho 2006; Ríos & Duffy, 2007; Hultgren et al. 2011; Anker et al. 2012, 2016; this study).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042664F1E1FECFBBB4D3BF82B.taxon	biology_ecology	Ecology: In coral reefs, coral rubble, and similar habitats in sublittoral areas with sponges abundant; commonly inhabiting sponges of the genus Agelas Duchassaing & Michelotti, 1864 (Anker et al. 2016); forming heterosexual pairs; 5 – 80 m (Anker et al. 2016; this study). Sampled at continental shelf off Recife (DZ / UFRGS 7049; MOUFPE 21542) in a substrate of sediment, macroalgae, coral rubble, and sponges.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042664F1E1FECFBBB4D3BF82B.taxon	discussion	Remarks: The examined material was sampled at a depth of 8 m in Fernando de Noronha and between 50.8 and 80 m on the continental shelf off Recife, extending the bathymetric range of this species from 56 m (Anker et al. 2016) to 80 m. One specimen (male, DZ / UFRGS 7044) exhibited a slight morphological variation in the fixed finger of the major chela, which was much shorter than the dactylus (vs. slightly shorter in length in Pequegnat & Heard 1979) (see Pequegnat & Heard 1979, Figs. 3 A, B).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042674F1F1FECFF4F4F83FCE0.taxon	materials_examined	Material examined: Maranhão — Turiaçu: 1 M, Nordeste Expedition II, St. 111 / 112, MOUFPE 12510; Pernambuco — Continental Shelf off Recife: 1 M, 1 OV, 10. v. 2018, 08 ° 23 ′ 04.3 ′′ S 34 ° 40 ′ 07 ′′ W, 80.0 m depth, in sponge, DZ / UFRGS 7050; Bahia — Salvador: 1 M, Almirante Saldanha Expedition, St. 1981, 23. ix. 1968, 13 ° 48.5 ′ S 38 ° 48.5 ′ W, 49.0 m depth, MOUFPE 9212.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042674F1F1FECFF4F4F83FCE0.taxon	description	Description: Coutière (1909), Ríos & Duffy (2007), Anker & Pachelle (2014).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042674F1F1FECFF4F4F83FCE0.taxon	distribution	Distribution: Bahamas (Andros Island), Belize (Carrie Bow Cay), Jamaica, Barbados and Brazil (Maranhão, Pernambuco, Bahia and Espírito Santo: Vitória-Trindade chain) (Coutière, 1909; Dardeau 1984; Coelho et al. 2006; Ríos & Duffy, 2007; Macdonald et al. 2009; Hultgren et al. 2011; Anker & Pachelle 2014; this study).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042674F1F1FECFF4F4F83FCE0.taxon	biology_ecology	Ecology: In association with sponges [e. g., Aiolochroia crassa (Hyatt, 1875), Hyattella intestinalis Lamarck, 1814, Hymeniacidon caerulea Pulitzer-Finali, 1986]; solitarily or in heterosexual pairs; 14 – 80 m (Anker & Pachelle 2014; Ríos & Duffy, 2007; this study). Sampled at the continental shelf off Recife (DZ / UFRGS 7050) in association with an unidentified sponge.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042674F1F1FECFF4F4F83FCE0.taxon	discussion	Remarks: Synalpheus androsi can be identified by the distinct morphology of the third pair of pereiopods, which display a noticeable concavity on the flexor margins of the merus, carpus, and propodus (see Fig. 4 B) (Coutière, 1909; Ríos & Duffy, 2007). This study extends the known bathymetric range of the species from 55 m (Anker & Pachelle 2014) to 80 m.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042674F1F1FECFC844B10FA98.taxon	materials_examined	Material examined: Maranhão — Turiaçu: 1 M, Almirante Saldanha Expedition, St. 1751, 06. xi. 1967, 00 ° 37.0 ′ S 44 ° 40.0 ′ W, 44.0 m depth, MOUFPE 8795; Pernambuco — Goiana: 1 M, 1 OV, Praia de Pontas de Pedra, 07 ° 37 ′ 00 ′′ S 34 ° 48 ′ 51 ′′ W, 1.0 m depth, in the sponge Haliclona implexiformis Hechtel, 1965, MOUFPE 21600; Sergipe — 2 M, Plataforma Pcm 11 Pós. Face Externa Pé: Fora Superfície Externa, MOUFPE 15791; Bahia — 1 M, Nordeste Expedition III, St. 181, MOUFPE 13050.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042674F1F1FECFC844B10FA98.taxon	description	Description: Coutière (1909), as Synalpheus minus antillensis, and Anker et al. (2012).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042674F1F1FECFC844B10FA98.taxon	distribution	Distribution: Gulf of Mexico (off Texas), Caribbean Sea (from Yucatan Peninsula to Venezuela), and Brazil (Abrolhos, Rocas Atoll, Trindade Island, Maranhão and from Ceará to São Paulo) (Anker et al. 2012, 2016; Soledade et al. 2015; this study).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042674F1F1FECFC844B10FA98.taxon	biology_ecology	Ecology: In coral reefs, coral rubble, coralline algae, and sponges (e. g., Ircinia sp.); mostly in heterosexual pairs; intertidal to 42 m (Anker et al. 2012, 2016). The material from Goiana, Pernambuco (MOUFPE 21600), was found in heterosexual pairs inhabiting coral rubble and sponges (H. implexiformis).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042674F1F1FECFC844B10FA98.taxon	discussion	Remarks: This species is recorded in association with the sponge H. implexiformis for the first time.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042674F101FECFA184D65FEEB.taxon	materials_examined	Material examined: Maranhão — São José de Ribamar: 1 F, Praia de Araçagi, MOUFPE 9111; Pernambuco — Cabo de Santo Agostinho: 2 F, Baía de Suape, 8 ° 21 ′ 54 ′′ S 34 ° 56 ′ 50 ′′ W, MOUFPE 21871; Goiana: 1 M, 1 OV, Milênio Project, St. 03, Rio Carrapicho, 11. ii. 2004, MOUFPE 15783; 1 M, Praia de Pontas de Pedra, 07 ° 37 ′ 00 ′′ S 34 ° 48 ′ 51 ′′ W, 1.0 m depth, MOUFPE 21873; Ilha de Itamaracá: 1 M, MOUFPE 8897; Paulista: 1 M, Praia de Maria Farinha, MOUFPE 8788; Continental Shelf off Recife: 1 M, 07. ii. 2018, 8 ° 08 ′ 51.5 ′′ S 34 ° 34 ′ 08.0 ′′ W, 65.0 m depth, in sponge, MOUFPE 21803.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042674F101FECFA184D65FEEB.taxon	description	Description: Coutière (1909) and Anker et al. (2012).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042674F101FECFA184D65FEEB.taxon	distribution	Distribution: USA (Florida), Gulf of Mexico, Bahamas, Caribbean Sea, Suriname, and Brazil (from Amapá to Santa Catarina and seamounts of the North Chain) (Chace 1972; Lemaitre 1984; Christoffersen 1998; Coelho-Filho 2006; Anker et al. 2012).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042674F101FECFA184D65FEEB.taxon	biology_ecology	Ecology: On rocky shores with high concentration of sponges, ascidians and coral rubble; in crevices of coral rocks, among ascidians, bryozoans and sponges; in mangrove areas, either among the roots or in shipwormperforated mangrove wood; mostly in heterosexual pairs; intertidal to 65 m (Pequegnat & Ray 1974; Rodríguez 1980; Anker et al. 2012; this study).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042674F101FECFA184D65FEEB.taxon	discussion	Remarks: The present study extends the known bathymetric depth of S. apioceros from 20 m (Pequegnat & Ray 1974) to 65 m. This species exhibits notable morphological variation and has been suggested as a potential species complex (Anker et al. 2012). Further studies are required to comprehensively assess the extent of morphological variation within what is currently recognized as S. apioceros.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042694F131FECFF4F4CFDFDCB.taxon	materials_examined	Material examined: Pernambuco — Continental Shelf off Recife: 2 M, 27. ii. 2018, 8 ° 13 ′ 33.0 ′′ S 34 ° 37 ′ 40.3 ′′ W, 50.6 m depth, DZ / UFRGS 7066 (genetic voucher, GenBank access PV 273119); 1 F, same data as DZ / UFRGS 7066, in sponge, MOUFPE 21870.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042694F131FECFF4F4CFDFDCB.taxon	description	Description: Armstrong (1949).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042694F131FECFF4F4CFDFDCB.taxon	distribution	Distribution: Dominican Republic, Panama, Brazil (Pernambuco) (Armstrong, 1949; Duffy 1992; this study).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042694F131FECFF4F4CFDFDCB.taxon	biology_ecology	Ecology: In association with the coral Agaricia agaricites Linnaeus, 1758, and in coral rubble (Armstrong, 1949; Duffy 1992); 50.6 m (Dardeau 1984; De Grave & Anker 2017; this study). Sampled at continental shelf off Recife (DZ / UFRGS 7066; MOUFPE 21870) in association with unidentified sponges.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042694F131FECFF4F4CFDFDCB.taxon	discussion	Remarks: Synalpheus barahonensis is characterized by the presence of four articles in the carpus of the second pair of pereiopods (Fig. 5 F), the basicerite unarmed dorsally, and a ventrolateral spine almost equal in length to the distolateral tooth of the scaphocerite (Fig. 5 A; Armstrong, 1949, Fig. 7). Additional characters include the tip of the ultimate article of the third maxilliped bearing a series of setae (Fig. 6 D) [vs. a set of spiniform setae, as in most Synalpheus species (Ríos & Duffy, 2007; Anker et al. 2012)], and the second to fifth pleurae of males tapering to a sharp point ventrally (Armstrong, 1949; Dardeau 1984). The species is considered rare (De Grave & Anker 2017) and remains poorly understood in terms of biological aspects. This study represents the first record of S. barahonensis in the southwestern Atlantic, and provides the initial data on its depth range (50.6 m), and offers the first 16 S gene sequence information for the species.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60426B4F131FECFD5B4E95F801.taxon	materials_examined	Material examined: Pernambuco — Continental Shelf off Recife: 1 F, 27. ii. 2018, 8 ° 13 ′ 33.0 ′′ S 34 ° 37 ′ 40.3 ′′ W, 50.6 m depth, in sponge, DZ / UFRGS 7051; Fernando de Noronha: 1 F, Ponta da Sapata, 30. vi. 2022, 03 º 51.892 ′ S 32 º 27.965 ’ W, 11.0 m depth, in sponge, DZ / UFRGS 7041.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60426B4F131FECFD5B4E95F801.taxon	description	Description: Anker & Tóth (2008).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60426B4F131FECFD5B4E95F801.taxon	distribution	Distribution: Belize, Jamaica, Curaçao, Barbados and Brazil (Fernando de Noronha and Pernambuco) (Anker & Tóth, 2008; Macdonald et al. 2009; Hultgren et al. 2010, 2011; this study).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60426B4F131FECFD5B4E95F801.taxon	biology_ecology	Ecology: Often in association with sponges (e. g., Xestospongia sp.) or coral rubble with sponges (Anker & Tóth, 2008; Hultgren et al. 2010); records of co-occurrence in the same host sponge with individuals of the S. paraneptunus complex (S. bocas Anker & Tóth, 2008, and S. duffyi Anker & Tóth, 2008) (Macdonald et al. 2009); in heterosexual pairs; 12 – 50.6 m (Anker & Tóth, 2008; this study). The material analyzed (DZ / UFRGS 7041, 7051) was found in unidentified sponges.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60426B4F131FECFD5B4E95F801.taxon	discussion	Remarks: Synalpheus belizensis belongs to the S. paraneptunus complex, which also includes S. bocas, S. brevidactylus Anker & Tóth, 2008, S. duffyi, S. microneptunus Hultgren, Macdonald & Duffy, 2011, S. maxillispinus, S. paraneptunus, and S. riosi Anker & Tóth, 2008 (Anker & Pachelle 2014). The species is characterized by a rostrum and orbital teeth subequal in length, proximally broadened and tapering distally; the stylocerite surpassing the distal margin of the first antennular segment; the presence of a scaphocerite blade (Fig. 7 A); the carpus of the second pereiopod having five articles, the first approximately four times as long as the second (Fig. 7 F) (Anker & Tóth, 2008). Additional distinguishing characters include the fixed and movable fingers of the minor chela excavated on the cutting edge, with the dorsal surface of the dactylus with scattered gambarelloid setae (Figs. 7 D, E); the distal tip of the third maxilliped bearing a set of spiniform setae (Fig. 8 D), and the uropodal exopod armed with a distolateral tooth (Fig. 8 C) (Anker & Tóth, 2008; Anker et al. 2012). Anker & Tóth (2008) initially stated that the scaphocerite blade is absent in S. belizensis. However, their figures 12 A and B, illustrate its presence, which is also mentioned in other sections of the text. Interestingly, the male paratype of the species differs from the holotype by having longer orbital teeth, by the absence of scaphocerite blade on the left side, but a small blade on the right side and by the slightly longer second antennular segment (Anker & Tóth, 2008). Hultgren et al. (2010) documented additional variations in scaphocerite blade development, ranging from 50 % to 80 % of the scaphocerite lateral spine’s length. The following variations were observed in our material: one individual (1 F, DZ / UFRGS 7041) has the dactylus of the major chela as long as the fixed finger, and a slightly longer distodorsal spine (Figs. 7 B, C) (vs. dactylus of the major chela subequal to fixed finger and a shorter distodorsal spine; see Anker & Tóth, 2008, figs. 11 A – C); another individual (1 F, DZ / UFRGS 7051) has slightly longer rostrum and orbital hoods (vs. not produced rostrum and orbital hoods), major chela fingers squared (vs. rounded / pointed major chela fingers), and distodorsal region of the major chela with a very short and rounded tubercle (vs. distodorsal region of the major chela with a sharp and directed anteriorly spine) (see Anker & Tóth, 2008, figs. 12 A, B, and 11 A – C). These variations were identified by Anker & Tóth (2008) as intraspecific, but further sampling and molecular analyses are necessary to determine the full extent of morphological variability within the species. This study represents the first record of S. belizensis in the southwestern Atlantic and extends its known bathymetric distribution from 12 m (Anker & Tóth, 2008) to 50.6 m.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60426E4F161FECFF4F4DAEFC1B.taxon	materials_examined	Material examined: None.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60426E4F161FECFF4F4DAEFC1B.taxon	description	Description: Chace (1972), Dardeau (1984), Macdonald & Duffy (2006), Ríos & Duffy (2007), and Anker et al. (2012).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60426E4F161FECFF4F4DAEFC1B.taxon	distribution	Distribution: Bahamas, Gulf of Mexico, Caribbean Sea, and Brazil (Rocas Atoll) (Chace 1972; Ríos & Duffy, 2007; Hultgren et al. 2010, 2011; Anker et al. 2012).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60426E4F161FECFF4F4DAEFC1B.taxon	biology_ecology	Ecology: On bottoms with abundance of coral rubble and sponges [e. g., H. intestinalis, H. caerulea, Ectyoplasia ferox (Duchassaing & Michelotti, 1864), cited in Ríos & Duffy (2007) as Hymeniacidon amphilecta, A. crassa, cited in Ríos & Duffy (2007) as Pseudoceratina crassa] (Ríos & Duffy, 2007; see Table 1 in Anker et al. 2012 for more records); in heterosexual pairs or in groups composed of several adult individuals in an approximately equal sex ratio; 5 – 20 m (Ríos & Duffy, 2007; Anker et al. 2012).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60426E4F161FECFF4F4DAEFC1B.taxon	discussion	Remarks: Synalpheus bousfieldi, along with S. brooksi, S. carpenteri Macdonald & Duffy, 2006, S. chacei Duffy, 1998, S. corallinus Macdonald, Hultgren & Duffy, 2009, S. plumosetosus Macdonald, Hultgren & Duffy, 2009, S. ruetzleri Macdonald & Duffy, 2006, and S. thele Macdonald, Hultgren & Duffy, 2009, belongs to the S. brooksi complex (Ríos & Duffy, 2007; Macdonald et al. 2009; Anker et al. 2012). In Brazil, S. bousfieldi has been reported from Amapá to Ceará (Christoffersen 1979; Coelho-Filho 2006) and Rocas Atoll (Anker et al. 2012). Records of this species in different studies (e. g., Ríos & Duffy, 2007; Hultgren et al. 2010, 2011) consistently cite Christoffersen (1979) as the reference for Brazilian records. However, the author did not provide any specific comments regarding its occurrence in Brazil. Similarly, Coelho-Filho (2006) reported the species from Ceará, but did not include illustrations or detailed morphological remarks of the analyzed material. In the present study, no specimens of S. bousfieldi were found. Conversely, Anker et al. (2012) provided illustrations and accession numbers for material collected at Rocas Atoll, offering a more reliable record. Based on this evidence, the distribution of S. bousfieldi should be considered confirmed only for the Rocas Atoll.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60426E4F171FECFBE74C12FE7F.taxon	materials_examined	Material examined: Pernambuco — Continental Shelf off Recife: 1 M, 27. ii. 2018, 8 ° 13 ′ 52.1 ′′ S 34 ° 37 ′ 39.1 ′′ W, 50.8 m depth, in sponge, MOUFPE 21537; 1 M, same data as MOUFPE 21537, MOUFPE 21555; Sergipe — 3 M, Plataforma Pdo 2 Face Externa Pé: Terra Fundo, 30. x. 2000, MOUFPE 15787.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60426E4F171FECFBE74C12FE7F.taxon	description	Description: Herrick (1891), as Alpheus saulcyi f. brevicarpus Herrick, 1891, and Coutière (1909).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60426E4F171FECFBE74C12FE7F.taxon	distribution	Distribution: Bermuda, USA (Florida), Gulf of Mexico, Bahamas, West Indies, Panama, Venezuela, and Brazil (from Ceará to Rio Grande do Sul) (Christoffersen 1979, 1998; Bezerra & Coelho 2006; Cházaro-Olvera & Vázquez-López 2014; Velásquez et al. 2017; as references as S. brevicarpus).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60426E4F171FECFBE74C12FE7F.taxon	biology_ecology	Ecology: Muddy and sandy bottoms, coral rubble, and under rocks; in association with sponges (e. g., Ircinia sp., Haliclona sp., Spongia sp., and Zygomycale sp.), ascidians, and in reefs of Phragmatopoma sp.; intertidal to 51 m (Christoffersen 1979; Velásquez et al. 2017).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60426E4F171FECFBE74C12FE7F.taxon	discussion	Remarks: Synalpheus brevicarpus belongs to the S. brevicarpus complex, which includes the eastern Pacific S. digueti Coutière, 1909 and S. pinkfloydi Anker, Hultgren & De Grave, 2017, and the western Atlantic S. antillensis, S. minus, and S. ubatuba (Anker et al. 2017; Mantelatto et al. 2023). Santos et al. (2012), when analyzing material identified as S. cf. brevicarpus, found two distinct color patterns, suggesting the presence of at least two species in southern Bahia. However, part of their material (e. g., the specimen with the pinkish color pattern on the major chela, Fig. 4 D) was mistakenly attributed to S. antillensis (see Soledade et al. 2015). Almeida et al. (2018 b) also reported two color patterns in specimens of S. brevicarpus from São Paulo: one with the distal portion of the palm and fingers of the major chela exhibiting a pink / orange coloration (S. cf. brevicarpus - pink / orange chela) and another with a green / blue coloration (S. cf. brevicarpus - green / blue chela). Mantelatto et al. (2023) subsequently described the S. cf. brevicarpus (green / blue chela) material from São Paulo as a new species, S. ubatuba. Based on color pattern, part of the material from Bahia initially referred to as S. cf. brevicarpus by Almeida et al. (2012) and Santos et al. (2012) was also reassigned to S. ubatuba. Additionally, Mantelatto et al. (2023) identified the S. cf. brevicarpus (pink / orange chela) material analyzed by Almeida et al. (2018 b) as corresponding to S. minus. Mantelatto et al. (2023) highlighted some morphological differences between S. ubatuba and S. brevicarpus, such as the morphology of the basicerite, which in the former is armed with a long, strong distoventral tooth (vs. dorsal margin with a short, subacute point in S. brevicarpus), and the distolateral tooth of the scaphocerite, which is as long as the antennular peduncle in S. ubatuba (vs. not reaching the end of the antennular peduncle in S. brevicarpus). These same morphological differences were observed in the material examined in this study. Additionally, the coloration of the major chelae could not be assessed due to pigment dilution caused by ethanol preservation, nor could molecular analyses be conducted. Given the uncertainty surrounding the identity of the material, S. brevicarpus was not excluded from the checklist.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60426F4F171FECFE024B4EF96F.taxon	materials_examined	Material examined: Pernambuco — Continental Shelf off Recife: 1 OV, 27. ii. 2018, 8 ° 13 ′ 52.1 ′′ S 34 ° 37 ′ 42.7 ′′ W, 50.0 m depth, in sponge, DZ / UFRGS 7052; 1 OV, same data as DZ / UFRGS 7052, MOUFPE 21815; 1 M, 27. ii. 2018, 8 ° 13 ′ 36.8 ′′ S 34 ° 37 ′ 41.9 ′′ W, 51.0 m depth, in sponge, MOUFPE 21813; 1 M, 27. ii. 2018, 8 ° 13 ′ 52.1 ′′ S 34 ° 37 ′ 41.2 ′′ W, 51.8 m depth, in sponge, DZ / UFRGS 7053.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60426F4F171FECFE024B4EF96F.taxon	description	Description: Anker & Tóth (2008).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60426F4F171FECFE024B4EF96F.taxon	distribution	Distribution: Panama and Brazil (Pernambuco) (Anker & Tóth, 2008; this study).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60426F4F171FECFE024B4EF96F.taxon	biology_ecology	Ecology: Associated with the sponges Neopetrosia subtriangularis (Duchassaing, 1850) and Calyx podatypa (Laubenfels, 1934), growing on substrates such as coral rubble and seagrass; in heterosexual pairs; 1 – 51.8 m (Anker & Tóth, 2008; this study). Sampled at the continental shelf off Recife (all lots cited above) in association with sponges, on coral rubble and algae bottom, at depths from 50 – 51.8 m.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60426F4F171FECFE024B4EF96F.taxon	discussion	Remarks: Synalpheus brevidactylus is characterized by a rostrum distinctly longer than the orbital teeth, broad at the base and tapering to the tip; by the fixed and movable fingers of the minor chela excavated on the cutting edges, with the dactylus bearing scattered gambarelloid setae on dorsal surface; by the uropodal exopod armed with two to three lateral teeth (Figs. 10 B, C); and by the telson presenting a longitudinal median depression (Fig. 10 D) (Anker & Tóth, 2008; Anker et al. 2012; this study). Additional diagnostic characters are: the carpus of the second pair of pereiopods divided into five articles, with the first four times as long as the second (Fig. 9 F), the third maxilliped ending in a set of six or seven spiniform setae (Fig. 10 E), and the palm of the major chela is approximately three times as long as the fingers (Anker & Tóth, 2008). The material examined revealed morphological variations when compared to the original description of the species. For instance, a male specimen (MOUFPE 21813) exhibited a rostrum and orbital teeth that were subequal in length, with the rostrum being narrower (vs. rostrum longer and broader than the orbital teeth) (for comparison, see Fig. 9 A and Anker & Tóth, 2008, Fig. 8 A). The fingers of the major chela were strongly unequal in length, with the dactylus being square / rounded and longer than the fixed finger (vs. dactylus slightly longer and more bulging than the fixed finger) (see Figs. 9 B, C, and Anker & Tóth, 2008, Figs. 8 C, E). Additionally, the distodorsal tooth of the basicerite is slightly more acute (vs. distodorsal margin of the basicerite with a subacute point). The blade of the scaphocerite is longer, extending beyond the ventrolateral tooth of the basicerite and reaching the end of the distolateral tooth of the scaphocerite (vs. blade of scaphocerite reaching the end of the ventrolateral tooth of the basicerite and halfway to the distolateral tooth of the scaphocerite) (for comparison, see Fig. 9 A and Anker & Tóth, 2008, Fig. 8 A). In another specimen (1 OV, MOUFPE 21815), the tooth of the right orbital hood is partially fused to the rostrum (vs. typical tridentate front) and the uropodal exopod had three fixed teeth on the right side and two on the left (vs. uropodal exopod with three or four fixed teeth in both sides) (see Anker & Tóth, 2008, Figs. 8 I, K). This study provides the first record of S. brevidactylu s in the southwestern Atlantic and expands its known bathymetric distribution from 3 (Anker & Tóth, 2008) to 51.8 m.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60426F4F081FECF9324B5FF863.taxon	materials_examined	Material examined: Maranhão — Turiaçu: 4 M, Almirante Saldanha Expedition, St. 1749 A, 06. xi. 1967, 00 ° 03.0 ′ S 44 ° 32.3 ′ W, 63.0 m depth, MOUFPE 8746; Ceará — Acaraú: 3 M, 1 OV, 1 F, Almirante Saldanha Expedition, St. 1710, 27. x. 1967, 02 ° 39.5 ′ S 39 ° 46.0 ′ W, 17.0 m depth, MOUFPE 8743; 5 M, same data as MOUFPE 8743, MOUFPE 8756; Fortaleza: 1 M, Parque Estadual Marinho da Pedra da Risca do Meio, 15. vii. 2004, in Monanchora arbuscula, MOUFPE 21868; Paracuru: 1 M, Almirante Saldanha Expedition, St. 1708 A, 22. x. 1967, 02 ° 44.3 ′ S 39 ° 04.0 ” W, 54.0 m depth, MOUFPE 8762; 1 OV, Almirante Saldanha Expedition, St. 1701, MOUFPE 8741; 49 M, Pavasas Expedition - DG 03, 19. vii. 1987, MOUFPE 8749; Pernambuco — Fernando de Noronha: 1 M, Buraco do Inferno, 18. vi. 2019, 03 ° 48.968 ′ S 32 ° 23.577 ′ W, 13.0 – 15.0 m depth, in sponge, DZ / UFRGS 6712; 1 M, same data as DZ / UFRGS 6712, DZ / UFRGS 6713; 1 M, 2 OV, Cagarras, 25. vi. 2022, 03 ° 50.933 ′ S 32 ° 26.178 ′ W, 13.0 m depth, in sponge, DZ / UFRGS 7026; 4 M, 2 OV, Buraco do Inferno, 26. vi. 2022, 03 ° 48.968 ′ S 32 ° 23.577 ′ W, 12.0 m depth, in sponge, DZ / UFRGS 7030; 2 M, 2 F, Ilha do Meio, 26. vi. 2022, 03 ° 49.015 ′ S 32 ° 23.549 ′ W, 11.0 m depth, in sponge, DZ / UFRGS 7036; 1 M, Ponta da Sapata, 30. vi. 2022, 03 º 51.892 ′ S 32 º 27.965 ′ W, 11.0 m depth, in sponge, DZ / UFRGS 7042; 1 M, Laje Dois Irmãos, 30. vi. 2022, 03 ° 51.859 ′ S 32 ° 27.934 ′ W, 17.0 m depth, in sponge, DZ / UFRGS 7045; Continental Shelf off Recife: 45 M, 7 F, 2 NI, 27. ii. 2018, 8 ° 13 ′ 33.0 ′′ S 34 ° 37 ′ 40.3 ′′ W, 50.6 m depth, in sponge, MOUFPE 21816; 2 M, 10. v. 2018, 08 ° 23 ′ 04.3 ′′ S 34 ° 40 ′ 07 ′′ W, 80.0 m depth, in sponge, MOUFPE 21818; 1 M, same data as MOUFPE 21818, MOUFPE 21825; 2 M, same data as MOUFPE 21818, MOUFPE 21826; 2 M, same data as MOUFPE 21818, MOUFPE 21842; 1 M, same data as MOUFPE 21818, MOUFPE 21855; 1 M, 07. ii. 2018, 8 ° 08 ′ 43.7 ′′ S 34 ° 34 ′ 22.6 ′′ W, 54.0 m depth, MOUFPE 21559; 1 M, same data as MOUFPE 21559, in rhodoliths, MOUFPE 21564; 1 M, 10. v. 2018, 08 ° 21 ′ 34.9 ′′ S 34 ° 41 ′ 53.3 ′′ W, 50.8 m depth, in sponge, MOUFPE 21791; 1 M, 27. ii. 2018, 8 ° 13 ′ 52.1 ′′ S 34 ° 37 ′ 41.2 ′′ W, 51.8 m depth, MOUFPE 21549; Ilha de Itamaracá: 11 M, 17. i. 1969, 7 ° 49 ′ S 34 ° 49 ′ 13 ′′ W, 0.8 m depth, MOUFPE 8753; Recife: 18 M, 4 F, 2 NI, Boa Viagem, 24. xi. 1964, in sponge, MOUFPE 8757.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60426F4F081FECF9324B5FF863.taxon	description	Description: Macdonald & Duffy (2006) and Anker et al. (2012).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60426F4F081FECF9324B5FF863.taxon	distribution	Distribution: USA (Florida), Gulf of Mexico, Bahamas, Caribbean Sea, Suriname and Brazil (Fernando de Noronha, Abrolhos, and from Amapá to Bahia) (Chace 1972; Christoffersen 1979, 1998; Ríos & Duffy, 2007; Alves et al. 2008; Anker et al. 2012; Soledade et al. 2015).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60426F4F081FECF9324B5FF863.taxon	biology_ecology	Ecology: Coral reef areas, associated with coral rubble, calcareous algae, seagrass banks, and sponges (e. g., Agelas sp., Ircinia sp., Lissodendoryx sp., and Spheciospongia sp.); in heterosexual pairs, associated with H. caerulea; also forming “ subsocial ” groups, with densities varying from 10 to 1000 individuals, with few ovigerous females among them (Ríos & Duffy, 2007); intertidal to 82.3 m, most commonly up to 10 m (Christoffersen 1979; Dardeau 1984; Ríos & Duffy, 2007; Anker et al. 2012). Ecological notes regarding our material, especially those related to association with sponges, are provided in the remarks and in the Discussion section.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60426F4F081FECF9324B5FF863.taxon	discussion	Remarks: Synalpheus brooksi is one of the most widely distributed species of Synalpheus in the western Atlantic (Macdonald & Duffy 2006; Anker et al. 2012). The specimen from Parque Estadual Marinho da Pedra da Risca do Meio, Fortaleza, Ceará, previously cited by Bezerra & Coelho (2006) as S. townsendi (without access number), actually correspond to S. brooksi (MOUFPE 21868) (this study). Some morphological variations were observed in our material in comparison to the redescription provided by Dardeau (1984). In three females (1 OV, MOUFPE 8741; 1 OV, and 1 F, MOUFPE 8743), the pleura of the third and fourth segments are rounded (vs. third and fourth pleura subrectangular to tapered) (Dardeau 1984, Fig. 12 C). One of these females (OV, MOUFPE 8741) exhibited only one pair of dorsal spiniform setae on the telson (vs. typically two pairs; see Dardeau 1984, Fig. 12 F), two distolateral teeth on the uropodal exopod (vs. one distolateral tooth; see Dardeau 1984, Fig. 12 F), and the rostrum and orbital hoods were poorly produced, with the tridentate front being wider than long (vs. produced rostrum and orbital hoods, with tridentate front being longer than wide; see Dardeau 1984, Fig. 12 A) Interestingly, eight males carried embryos on their pleopods (1 M, MOUFPE 8746; 4 M, MOUFPE 8749; 2 M, MOUFPE 8753; 1 M, MOUFPE 21816), a surprising observation given the absence of ovigerous setae and the presence of pleura characteristics typical of Synalpheus males. This behavior has been previously reported for this species by Coutière (1909), Chace (1972), Dardeau (1984), and Anker et al. (2012). Notably, ovigerous females were found in the same jars as these males, suggesting a potential collective caregiving behavior for offspring within “ subsocial ” groups. Ethological studies are needed to further investigate this phenomenon. We recorded a possible subsocial group with a total of 54 specimens associated with a sponge (Fig. 3 C) on the continental shelf off Recife, Pernambuco (MOUFPE 21816). Among them, two individuals (1 M and 1 F) possessed two pairs of minor chelae. Additionally, one S. herricki specimen (1 M, DZ / UFRGS 7067) was found co-occurring within the same sponge host. Parasitism was also observed, with some individuals exhibiting gill chambers infested by bopyrid isopods (1 M and 1 F, MOUFPE 21816) and pleons parasitized by rhizocephalans (MOUFPE 8746).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042734F0B1FECFF4F4C82FD3B.taxon	materials_examined	Material examined: Pernambuco — Continental Shelf off Recife: 1 M, 27. ii. 2018, 8 ° 13 ′ 33.0 ′′ S 34 ° 37 ′ 40.3 ′′ W, 50.6 m depth, in sponge, MOUFPE 21814; 1 M, 27. ii. 2018, 8 ° 13 ′ 52.1 ′′ S 34 ° 37 ′ 41.2 ′′ W, 51.8 m depth, in sponge, MOUFPE 21812.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042734F0B1FECFF4F4C82FD3B.taxon	description	Description: Macdonald et al. (2009).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042734F0B1FECFF4F4C82FD3B.taxon	distribution	Distribution: Jamaica (Discovery Bay) and Brazil (Pernambuco) (Macdonald et al. 2009; this study).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042734F0B1FECFF4F4C82FD3B.taxon	biology_ecology	Ecology: In sponges, associated with H. intestinalis (Macdonald et al. 2009); in heterosexual pairs; 50.6 – 51.8 m (Macdonald et al. 2009; Anker et al. 2012; this study). Sampled at the continental shelf off Recife (all lots cited above) in association with sponges, on coral rubble and algae bottom.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042734F0B1FECFF4F4C82FD3B.taxon	discussion	Remarks: S. corallinus is part of the S. brooksi complex (morphological differences regarding other species of the complex were discussed by Macdonald et al. 2009, Tab. 3, p. 12, Figs. 5 – 9). Our material agrees well with the description provided by Macdonald et al. (2009) (for comparison, see description and figures in Macdonald et al. 2009 and Figs. 11, 12 herein). The present study provides the first information regarding depth range for the species (50.6 – 51.8 m), as well as the first record of the species beyond its type locality (Discovery Bay, Jamaica), significantly expanding its known distribution.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042734F0B1FECFCC74F67FAA0.taxon	materials_examined	Material examined: Pernambuco — Tamandaré: 1 M, Carneiros, 20. vii. 2019, 8 ° 41 ′ 32 ′′ S 35 ° 4 ′ 25 ′′ W, 3.5 m depth, in sponge, MOUFPE 21620.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042734F0B1FECFCC74F67FAA0.taxon	description	Description: Ríos & Duffy (2007) and Oliveira et al. (2015).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042734F0B1FECFCC74F67FAA0.taxon	distribution	Distribution: USA (North Carolina, Florida), Belize, Panama, Curaçao, and Brazil (Pernambuco and Bahia) (Ríos & Duffy, 2007; Hultgren et al. 2010; Anker et al. 2012; Oliveira et al. 2015; this study).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042734F0B1FECFCC74F67FAA0.taxon	biology_ecology	Ecology: In sponges [Spheciospongia vesparium (Lamarck, 1815), Lissodendoryx colombiensis Zea & van Soest, 1986, and Ircinia cf. strobilina (Lamarck, 1816)]; on seagrass banks, among roots in mangroves with a high abundance of sponges; in heterosexual pairs; shallow waters to 65 m (Ríos & Duffy, 2007; Hultgren et al. 2010; Anker et al. 2012; Oliveira et al. 2015). Sampled in association with a sponge (unidentified).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042734F0B1FECFCC74F67FAA0.taxon	discussion	Remarks: Oliveira et al. (2015) highlighted differences between their material and the type series of the species, interpreting these as intraspecific variations (for more details, see Oliveira et al. 2015, Remarks and Fig. 2, and Ríos & Duffy, 2007, Figs. 3 – 6). The material analyzed in this study is consistent with the variations reported by Oliveira et al. (2015). Furthermore, with the new record, this study fills a gap in the species’ known distribution along the Brazilian coast.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042734F0C1FECFA7F4C9FF94B.taxon	materials_examined	Material examined: Rio Grande do Norte — São Pedro e São Paulo Archipelago: 3 F, 10 m depth, in an ARS, DZ / UFRGS 7068; 1 F, 0.1 m depth, in coral, DZ / UFRGS 7069; Paraíba — João Pessoa: 1 M, in coral reef, MOUFPE 8898; 1 M, 1 OV, Praia de Cabo Branco, 23. iii. 2023, under rocks, DZ / UFRGS 7054; Pernambuco — Fernando de Noronha: 2 M, MOUFPE 8793; Cabo de Santo Agostinho: 1 F, 16. vi. 2015, MOUFPE 21857; 2 M, Calhetas, 27. iv. 1990, MOUFPE 8877; 2 M, 2 OV, 5 F, Calhetas, 27. iii. 1990, MOUFPE 8882; 1 M, 1 OV, 1 F, Calhetas, 03. xii. 1990, 7 ° 50 ′ S 34 ° 49 ′ W, 1.0 – 3.0 m depth, MOUFPE 8888; 1 F, Calhetas, 09. viii. 1990, MOUFPE 8894; 1 M, Calhetas, 25. v. 1990, MOUFPE 8900; 1 OV, Calhetas, MOUFPE 8906; 2 M, Gaibu, MOUFPE 8809; 1 M, 1 OV, 1 F, Gaibu, 17. ix. 1989, MOUFPE 8883; 2 M, 1 OV, Praia do Paiva, 13. viii. 2015, MOUFPE 21859; 1 M, Praia do Paiva, 05. vii. 2007, under rocks, MOUFPE 15457; 1 M, 1 OV, Praia do Paraíso, 28. xi. 2019, 8 ° 21 ′ 54 ′′ S 34 ° 56 ′ 50 ′′ W, under rocks, MOUFPE 21863; 2 M, Baía de Suape, 05. vi. 1998, 8 ° 21 ′ 54 ′′ S 34 ° 56 ′ 50 ′′ W, MOUFPE 13156; 1 OV, Baía de Suape, 09. i. 1970, 7 ° 49 ′ S 34 ° 48 ′ W, 1.2 m depth, MOUFPE 8892; Goiana: 1 OV, Milênio Project St. 03, Rio Carrapicho, 11. ii. 2004, MOUFPE 15781; 1 M, 1 OV, Praia de Pontas de Pedra, 07 ° 37 ′ 00 ′′ S 34 ° 48 ′ 51 ′′ W, 1.0 m depth, associated with Dysidea etheria Laubenfels, 1936, MOUFPE 21601; 1 F, same data as MOUFPE 21601, associated with Amphimedon compressa Duchassaing & Michelotti, 1864, MOUFPE 21602; Ilha de Itamaracá: 1 M, Ilha de Itamaracá, St. 06, 08. i. 1989, 7 ° 43 ′ 36 ′′ S 34 ° 49 ′ 24 ′′ W, 3.7 m depth, MOUFPE 8878; 1 M, 1 F, Ilha de Itamaracá, St. 91, 1990, 7 ° 35 ′ 58 ′′ S 34 ° 48 ′ 33 ′′ W, 10.5 m depth, MOUFPE 8879; 1 M, 2 OV, Ilha de Itamaracá, St. 46, 1990, 7 ° 43 ′ 36 ′′ S 34 ° 49 ′ 24 ′′ W, 3.7 m depth, MOUFPE 8880; 2 M, 1 OV, 2 NI, Ilha de Itamaracá, St. 92, 03. xii. 1990, 7 ° 36 ′ S 34 ° 48 ′ W, 0.15 – 0.65 m depth, MOUFPE 8886; 1 M, 2 OV, Ilha de Itamaracá, St. 74, MOUFPE 8889; 1 M, 1 OV, Ilha de Itamaracá, St. 11, MOUFPE 8891; 1 OV, Ilha de Itamaracá, St. 41, 09. i. 1970, 7 ° 51 ′ S 34 ° 49 ′ W, 3.9 m depth, MOUFPE 8893; 1 OV, Ilha de Itamaracá, St. 30, MOUFPE 8895; 1 OV, Ilha de Itamaracá, St. 89, 03. xii. 1990, 7 ° 36 ′ 08 ′′ S 34 ° 48 ′ 33 ′′ W, 0.6 m depth, MOUFPE 8899; Jaboatão dos Guararapes: 1 M, 1 OV, 1 F, Candeias, 16. ix. 1989, MOUFPE 8876; 3 M, 3 OV, 1 F, Piedade, 18. iii. 1969, 7 ° 45 ′ 36 ′′ S 34 ° 48 ′ 00 ′′ W, 1.65 m depth, in coral reef, MOUFPE 8890; 1 M, Piedade, 22. xi. 1968, MOUFPE 8902; Recife: 1 F, Praia de Boa Viagem, 05. i. 2008, DZ / UFRGS 7055; 1 F, Praia de Boa Viagem, 05. i. 2008, MOUFPE 21872; Sirinhaém: 1 M, 1 F, Ilha de Santo Aleixo, MOUFPE 13442; 1 M, Ilha de Santo Aleixo, MOUFPE 13515; 4 M, 3 F, Ilha de Santo Aleixo, 05. vi. 2015, MOUFPE 21858; Tamandaré: 1 OV, Praia de Carneiros, 06. vi. 2019, 8 ° 41 ′ 32 ′′ S 35 ° 4 ′ 25 ′′ W, 2.0 m depth, under rocks, MOUFPE 21594; 1 M, Praia de Carneiros, iv. 1998, MOUFPE 10563; 1 OV, 1 F, Praia de Carneiros, 08. iv. 1997, MOUFPE 10566; Sergipe — 2 M, 2 F, Plataforma Pdo 2 Posição Face Externa Pé Fora Da Superfície, MOUFPE 15360; 2 M, 4 OV, Plataforma Pcb 4 Face, 01. xi. 2000, MOUFPE 15770; 3 M, 1 F, Plataforma Pcm 5 Pós: Face Externa Pé: Terra Superfície, MOUFPE 15771; 5 M, 5 OV, Plataforma Pcb 4 Face Externa Fora Fundo, 01. xi. 2000, MOUFPE 15772; 2 M, Plataforma PCM 11 Pós Face Externa Pé: Fora Superfície Externa, MOUFPE 15773; 2 M, 2 OV, 3 F, Plataforma Pd 02 Face Externa Terra Meio, 30. x. 2000, MOUFPE 15776; 1 M, 1 OV, Plataforma Pcm 5 Face Externa Pé: Fora Superfície, 30. x. 2000, MOUFPE 15780; 1 M, Plataforma Pcb 4 Face Externa Terra Superfície, 01. xi. 2000, MOUFPE 15782; Bahia — 1 M, BCAM 40 GAR 256 R 3 C 2 (environmental consultancy activity), xii. 2008, MOUFPE 15774; 1 F, Bioincrustação P 15 S R 2 C 2 (environmental consultancy activity), xii. 2008, MOUFPE 15775; 1 F, Bioincrustação P 25 S R 1 C 2 (environmental consultancy activity), xii. 2008, MOUFPE 15777; 1 OV, Bioincrustação P 45 S R 3 C 2 (environmental consultancy activity), xii. 2008, MOUFPE 15778; 1 OV, Bioincrustação P 210 S R 3 CR (environmental consultancy activity), MOUFPE 15779.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042734F0C1FECFA7F4C9FF94B.taxon	description	Description: Coutière (1909), Williams (1984), and Anker et al. (2012).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042734F0C1FECFA7F4C9FF94B.taxon	distribution	Distribution: USA (North Carolina to Florida), Gulf of Mexico, Honduras, Belize, Panama, Cuba, Jamaica, Dominican Republic, Colombia, Aruba, Venezuela, Saint Martin, Barbados, Bermuda, Brazil (Abrolhos, Fernando de Noronha, Rocas Atoll, São Pedro e São Paulo Archipelago, Trindade & Martin Vaz Archipelago, and from Ceará to Santa Catarina), Santa Helena and Ascension Islands (Anker et al. 2012 and references therein; 2016; Santos et al. 2012 and references therein; Soledade et al. 2015; this study).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042734F0C1FECFA7F4C9FF94B.taxon	biology_ecology	Ecology: Under rocks, in clusters of coralline algae, among roots in mangroves, in reefs of Phragmatopoma sp., and in association with cnidarians, bryozoans, and sponges (e. g. Amphimedon sp., Aplysina sp., Dysidea sp., Ircinia sp.); in heterosexual pairs; shallow waters to 51 m (Williams 1984; Frick et al. 2003; Anker et al. 2012; Cházaro-Olvera & Vázquez-López 2014; Almeida et al. 2015; this study). Also on gas platforms in the Colombian Caribbean region and on mussel farming lines in Santa Catarina (Macedo et al. 2012; Gracia et al. 2013). Part of the material examined was collected in coral and under rocks. Herein, we provide the first record of the species in the sponge Dysidea etheria.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042734F0C1FECFA7F4C9FF94B.taxon	discussion	Remarks: Synalpheus fritzmuelleri is one of the most common species of Synalpheus in the western Atlantic, with multiples records along the Brazilian coast (e. g., Christoffersen 1979, 1998; Anker et al. 2012; Santos et al. 2012; Soledade et al. 2015). Synalpheus fritzmuelleri is a possible species complex (Anker et al. 2012). A comprehensive study must be conducted to clarify the taxonomic status of the species, including the status of its three junior synonyms, originally described as varieties: S. f. caribaea Verrill, 1922, from Dominica Island; S. f. carolinensis Verrill, 1922, from North Carolina, USA; and S. f. elongatus Coutière, 1909, from Florida, USA (Coutière, 1909; Verrill 1922; Anker et al. 2012).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042744F0F1FECF8D64F95FE03.taxon	materials_examined	Material examined: Ceará — 2 M, Parque Estadual Marinho da Pedra da Risca do Meio, associated with Callyspongia (Cladochalina) aculeata (Linnaeus 1759), 22.0 m depth, MOUFPE 18389; Rio Grande do Norte — Natal: 1 M, Almirante Saldanha Expedition, St. 1657, 08. x. 1967, 05 ° 33.4 ′ S 35 ° 0.02 ′ W, 52.0 m depth, MOUFPE 8778.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042744F0F1FECF8D64F95FE03.taxon	description	Description: Coutière (1909), Verrill (1922), and Anker et al. (2012).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042744F0F1FECF8D64F95FE03.taxon	distribution	Distribution: Bermuda, USA (from North Carolina to Florida), Gulf of Mexico, Curaçao, Bonaire, Panama, Cuba, Venezuela, and Brazil (Abrolhos, Ceará, Rio Grande do Norte, and Bahia) (Christoffersen 1979, 1988; Rodríguez 1980; Bezerra & Coelho 2006, Anker et al. 2012; this study).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042744F0F1FECF8D64F95FE03.taxon	biology_ecology	Ecology: In shallow reefs and adjacent areas and seagrass (Christoffersen 1979). Associated with sponges [e. g., Callyspongia (Cladochalina) aculeata, Haliclona sp.], dead corals, rocks and Phragmatopoma sp. reefs; in heterosexual pairs; 1 – 51 m (Chace 1956 a; Hazlett 1962; Knowlton 1970; Christoffersen 1979; Bezerra & Coelho 2006; Anker et al. 2012; Velásquez et al. 2017; this study).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042744F0F1FECF8D64F95FE03.taxon	discussion	Remarks: The present study, with the new record (Rio Grande do Norte), fills a gap in the species distribution along the Brazilian coast.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042774F0F1FECFD9E4BAAF94B.taxon	materials_examined	Material examined: Ceará — 1 M, 3 OV, 1 F, Almirante Saldanha Expedition, St. 1701 A, 21. x. 1967, 01 ° 57.0 ′ S 37 ° 45.0 ′ W, 57.0 m depth, MOUFPE 8742; Pernambuco — Fernando de Noronha: 2 M, Laje Dois Irmãos, 17. vi. 2019, 03 ° 51.859 ′ S 32 ° 27.934 ′ W, 15.0 m depth, in sponge, DZ / UFRGS 6708; 1 M, same data as DZ / UFRGS 6708, DZ / UFRGS 6709; 3 M, Cagarras, 25. vi. 2022, 03 ° 50.933 ′ S 32 ° 26.178 ′ W, 13.0 m depth, in sponge, DZ / UFRGS 7027; 4 M, 2 F, Buraco do Inferno, 26. vi. 2022, 03 ° 48.968 ′ S 32 ° 23.577 ′ W, 12.0 m depth, in sponge, DZ / UFRGS 7032; 1 OV, 1 F, Ilha do Meio, 26. vi. 2022, 03 ° 49.015 ′ S 32 ° 23.549 ′ W, 11.0 m depth, in sponge, DZ / UFRGS 7038; 1 F, Ponta da Sapata, 30. vi. 2022, 03 º 51.892 ′ S 32 º 27.965 ′ W, 11.0 m depth, in sponge, DZ / UFRGS 7043; 11 M, 3 OV, 1 F, Laje Dois Irmãos, 30. vi. 2022, 03 ° 51.859 ′ S 32 ° 27.934 ′ W, 17.0 m depth, DZ / UFRGS 7046; Continental Shelf off Recife: 2 M, 27. ii. 2018, 8 ° 13 ′ 33.0 ′′ S 34 ° 37 ′ 40.3 ′′ W, 50.6 m depth, in sponge, DZ / UFRGS 7067; Sergipe — 4 M, 1 OV, MOUFPE 8754.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042774F0F1FECFD9E4BAAF94B.taxon	description	Description: Coutière (1909), Dardeau (1984), Ríos & Duffy (2007), Anker et al. (2012).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042774F0F1FECFD9E4BAAF94B.taxon	distribution	Distribution: USA (Florida), Gulf of Mexico, Mexico, Belize, Saint Martin, Panama (Bocas del Toro), Curaçao, and Brazil (Rocas Atoll, Fernando de Noronha, Ceará, Pernambuco, and Sergipe) (Chace 1972; Dardeau 1984; Ríos & Duffy, 2007; Hultgren et al. 2010; Anker et al. 2012; De Grave & Anker 2017; Horch et al. 2024; this study).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042774F0F1FECFD9E4BAAF94B.taxon	biology_ecology	Ecology: In sponges [e. g., Agelas dispar Duchassaing & Michelotti, 1864, A. crassa, Hymeniacidon amphilecta Laubenfels, 1936, H. intestinalis, and Ircinia sp.]; near coral reefs with an abundance of this type of host; in heterosexual pairs; from 5 – 73 m (Dardeau 1984; Rodríguez 1986; Ríos & Duffy, 2007; Anker et al. 2012).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042774F0F1FECFD9E4BAAF94B.taxon	discussion	Remarks: Synalpheus herricki can be distinguished from other western Atlantic Synalpheus by the ventral margins of the third and fourth pleurae of males having a “ W ” shape (see Dardeau 1984, Fig. 30 C) and by the dactylus of the major chela ending in a distinct spine directed ventrally, which is separated from the rest of the dactylus by a somewhat subtriangular notch (Fig. 13 B) (Dardeau 1984; Ríos & Duffy, 2007). Anker et al. (2012) documented several variations in specimens of S. herricki from Rocas Atoll, such as the absence of the rostrum and well-developed orbital teeth, in the number and position of spiniform setae of telson and in the shape of pleonal segment. The individuals sampled in Fernando de Noronha, Pernambuco, and Sergipe, presented some morphological variations compared to the original description by Coutière (1909) and the redescription by Dardeau (1984). These variations include the fingers of the second pair of pereiopods being longer than the palm (vs. as long as the palm) (Fig. 13 F; Dardeau 1984, fig. 28 C), and the absence of a sinus between the anterior and posterior portions of the third to fifth pleurae (vs. sinus present) (Fig. 14 A; Dardeau 1984, fig. 30 C). These variations highlight the need for integrative approaches to more accurately characterize the range of morphological differences within the species.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042774F001FECF8D64C09F8DF.taxon	materials_examined	Material examined: Pernambuco — Goiana: 2 M, 2 OV, Praia de Catuama, 20. i. 2023, 7 ° 39 ′ 18.6 ′′ S 34 ° 49 ′ 28.1 ′′ W, 1.5 m depth, in sponge, DZ / UFRGS 7057; Cabo de Santo Agostinho: 4 M, Baía de Suape, 16. viii. 2019, 8 ° 21 ′ 54 ′′ S 34 ° 56 ′ 50 ′′ W, 3.5 m depth, in sponge, MOUFPE 21521; 8 M, 1 OV, same data as MOUFPE 21521, associated with Echinodictyum dendroides Hechtel, 1983, MOUFPE 21513; 2 M, same data as MOUFPE 21521, MOUFPE 21510; 2 M, same data as MOUFPE 21521, in sponge, MOUFPE 21523; 5 M, same data as MOUFPE 21521, in sponge, MOUFPE 21508; 6 M, same data as MOUFPE 21521, in sponge, MOUFPE 21522; 5 M, same data as MOUFPE 21521, in sponge, MOUFPE 21509; 8 M, Baía de Suape, 21. iii. 2019, 8 ° 21 ′ 54 ′′ S 34 ° 56 ′ 50 ′′ W, 3.5 m depth, associated with E. dendroides, MOUFPE 21581; 2 M, same data as MOUFPE 21581, MOUFPE 21585; 6 M, 2 OV, same data as MOUFPE 21581, DZ / UFRGS 7056; 1 M, 1 OV, same data as MOUFPE 21581, DZ / UFRGS 7056; 6 M, same data as MOUFPE 21581, MOUFPE 21589; 4 M, 1 OV, Baía de Suape, 26. x. 2018, 8 ° 21 ′ 54 ′′ S 34 ° 56 ′ 50 ′′ W, 3.5 m depth, associated with E. dendroides, MOUFPE 21579; 6 M, same data as MOUFPE 21579, MOUFPE 21583; 1 M, same data as MOUFPE 21579, MOUFPE 21584; 2 M, same data as MOUFPE 21579, MOUFPE 21587; 35 M, 4 OV, 1 F, same data as MOUFPE 21579, in unindentified sponge, MOUFPE 21603; 1 OV, same data as MOUFPE 21579, MOUFPE 21526; 1 OV, same data as MOUFPE 21579, MOUFPE 21528; 1 OV, same data as MOUFPE 21579, MOUFPE 21530; 9 M, 2 OV, Baía de Suape, 26. iv. 2018, 8 ° 21 ′ 54 ′′ S 34 ° 56 ′ 50 ′′ W, 3.5 m depth, associated with E. dendroides, MOUFPE 21861; Tamandaré: 1 M, 1 OV, Praia de Carneiros, 06. vi. 2019, 8 ° 41 ′ 32 ′′ S 35 ° 4 ′ 25 ′′ W, 2.0 m depth, in sponge, MOUFPE 21595; 1 OV, same data as MOUFPE 21595, in rocks, MOUFPE 21596; 1 M, 1 OV, same data as MOUFPE 21595, in rocks, MOUFPE 21597; 2 M, Praia de Carneiros, 20. vii. 2019, 8 ° 41 ′ 32 ′′ S 35 ° 4 ′ 25 ′′ W, 3.5 m depth, associated with E. dendroides, MOUFPE 21610; 5 M, Praia de Carneiros, 20. vii. 2019, 8 ° 41 ′ 32 ′′ S 35 ° 4 ′ 25 ′′ W, 3.5 m depth, associated with E. dendroides, MOUFPE 21612; 1 M, same data as MOUFPE 21612, MOUFPE 21619; 1 M, 1 OV, same data as MOUFPE 21612, MOUFPE 21622; 2 M, same data as MOUFPE 21612, MOUFPE 21611; 37 M, 3 OV, Praia de Carneiros, 22. iii. 2019, 8 ° 41 ′ 32 ′′ S 35 ° 4 ′ 25 ′′ W, 3.5 m depth, associated with E. dendroides, DZ / UFRGS 7058 (genetic voucher, genbank access PV 273116, PV 273117); 2 M, 3 OV, 1 F, same data as DZ / UFRGS 7058, MOUFPE 21860.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042774F001FECF8D64C09F8DF.taxon	description	Description: Hultgren, Macdonald & Duffy (2010).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042774F001FECF8D64C09F8DF.taxon	distribution	Distribution: Panama (Bocas del Toro), Curaçao, Barbados, Venezuela, and Brazil (Pernambuco) (Hultgren et al. 2010, 2011; Hultgren & Duffy 2011; Anker et al. 2012; Rodríguez et al. 2020).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042774F001FECF8D64C09F8DF.taxon	biology_ecology	Ecology: Shallow regions of coral reefs, on rocks or in sponges (e. g., Agelas sp., Hyattella sp., Xestospongia sp.); in heterosexual pairs; shallow waters to 15 m (Hultgren et al. 2010; Anker et al. 2012; this study). Here, we record S. hoetjesi for the first time in association with the sponge E. dendroides. Ecological notes regarding our material are provided in the Remarks and in the Discussion section.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042774F001FECF8D64C09F8DF.taxon	discussion	Remarks: Synalpheus hoetjesi is characterized by the rostrum subequal in length although narrower than the orbital teeth, by the orbital teeth rounded to triangular (Fig. 15 A), by the ventrolateral tooth of the basicerite and the distolateral tooth of the scaphocerite being subequal in length (Fig. 15 A), by the lateral margin of the uropodal exopod with four to six teeth (in addition to the spiniform setae) (Fig. 16 B) and by the mesial spiniform setae on the posterior margin of the telson much thicker than the lateral (Fig. 16 D) (Hultgren et al. 2010). Although previous studies (e. g., Hultgren et al. 2010; Anker et al. 2012) have reported S. hoetjesi in heterosexual pairs, we observed S. hoetjesi in aggregations ranging from 3 to 46 individuals by host sponge, with varying proportions of males and females. It is also noteworthy that, as reported by Anker et al. (2012), specimens of S. ul, a species very similar to S. hoetjesi, were found at the same collection site and in the same species of sponge (Fig. 3 D). Synalpheus hoetjesi differs from S. ul by the thickness of the spiniform setae on the posterior margin of the telson, with the mesial more robust than lateral in S. hoetjesi (vs. mesial and lateral with approximately the same thickness in S. ul) (see Hultgren et al. 2010, Fig. 9). Hultgren et al. (2010) reported morphological variations in the spiniform setae of S. hoetjesi according to the sponge species in which these individuals were found, with mesial and lateral approximately the same thickness (see Hultgren et al. 2010, Fig. 9). In this study, one male specimen from Praia de Carneiros, Tamandaré (MOUFPE 21619), have four articles in both carpus of the second pereiopod, instead of five, as described for the species (Hultgren et al. 2010). This variation may suggest morphological plasticity in S. hoetjesi, although the potential influence of the host sponge on shrimp morphology was not evaluated in this study. Here, we report the first record and provide 16 S gene sequences for the species in the southwestern Atlantic, showing a 99.5 % similarity to sequences from individuals found in the Caribbean Sea (Barbados, Curaçao, and Panama) (phylogram Fig. 19) (see more details in the discussion).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60427D4F051FECFF4F4DDAFC50.taxon	materials_examined	Material examined: Pernambuco — Continental Shelf off Recife: 1 M, 1 OV, 07. ii. 2018, 8 ° 08 ′ 53.0 ′′ S 34 ° 34 ′ 07.4 ′ W, 68.0 m depth, in coral rubble, MOUFPE 21869; 1 M, 07. ii. 2018, 8 ° 08 ′ 44.2 ′′ S 34 ° 34 ′ 23.2 ′′ W, 55.0 m depth, DZ / UFRGS 7059; Ilha de Itamaracá: 1 M, Forte Orange, 28. iv. 1950, in sponge, MOUFPE 15807.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60427D4F051FECFF4F4DDAFC50.taxon	description	Description: Ríos & Duffy (2007).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60427D4F051FECFF4F4DDAFC50.taxon	distribution	Distribution: Belize (Carrie Bow Cay), Dominican Republic (Bayahibe), Panama (Bocas del Toro), and Brazil (Pernambuco) (Ríos & Duffy, 2007; Anker et al. 2012; this study).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60427D4F051FECFF4F4DDAFC50.taxon	biology_ecology	Ecology: Associated with the sponges H. intestinalis, H. caerulea, and an unidentified yellow tubular sponge; in heterosexual pairs; shallow reefs with abundance of sponges; depths up to 2 – 68 m (Ríos & Duffy, 2007; Anker et al. 2012; this study). Sampled in coral rubble and sponges.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60427D4F051FECFF4F4DDAFC50.taxon	discussion	Remarks: Synalpheus kensleyi is characterized by the rostrum narrower and slightly longer than the orbital teeth, the dorsal margin of the basicerite bearing an acute spine, by its ventrolateral tooth reaching half-length of the distolateral tooth of the scaphocerite (Fig. 17 A), by the major chela massive, with dactylus slightly exceeding the fixed finger and the distodorsal margin of the palm with a prominent tubercle with a spine directed downwards (see Ríos & Duffy, 2007, fig. 20 A). The species is considered rare and has been previously recorded only in the Caribbean (Anker et al. 2012; De Grave & Anker 2017). In this study, we provide the first record from the southwestern Atlantic. A male specimen from the continental shelf off Recife (MOUFPE 21869) has a more globose major chela, with dactylus noticeably longer than the fixed finger and more squared / rounded in shape (vs. more cylindrical / rectangular major chela, with dactylus slightly longer than the fixed finger and more elongated) (for comparison see Figs. 17 B, C and illustration of type material by Ríos & Duffy, 2007, fig. 20). The present study expands the known bathymetric distribution for the species from 2 (Ríos & Duffy, 2007) to 68 m.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60427D4F051FECFC2F4D14FAC7.taxon	materials_examined	Material examined: None.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60427D4F051FECFC2F4D14FAC7.taxon	description	Description: Anker & Pachelle (2014).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60427D4F051FECFC2F4D14FAC7.taxon	distribution	Distribution: Brazil (Bahia and Espírito Santo) (Anker & Pachelle 2014).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60427D4F051FECFC2F4D14FAC7.taxon	biology_ecology	Ecology: In sponges; 15 – 50 m (Anker & Pachelle 2014).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60427D4F051FECFC2F4D14FAC7.taxon	discussion	Remarks: Synalpheus maxillispinus is part of the S. paraneptunus complex, and is morphologically similar to S. bocas and S. belizensis (Anker & Pachelle 2014). For a detailed comparison and distinction among these species, refer to Anker & Tóth (2008) and Anker & Pachelle (2014).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60427D4F051FECFA5B4A84F8BB.taxon	materials_examined	Material examined: Paraíba — 1 M, Akaroa Expedition, St. 03, 08 º 56 ′ 15 ′′ S 34 º 57 ′ 40 ′′ W, MOUFPE 15788; Pernambuco — Continental Shelf off Recife: 1 F, 27. ii. 2018, 8 ° 13 ′ 52.1 ′′ S 34 ° 37 ′ 39.1 ′′ W, 50.8 m depth, in sponge, MOUFPE 21541; Ilha de Itamaracá: 1 M, Ilha de Itamaracá, St. 01, Forte Orange, MOUFPE 8789; 1 M, Forte Orange, 27. i. 1990, MOUFPE 8789.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60427D4F051FECFA5B4A84F8BB.taxon	description	Description: Coutière (1909) and Christoffersen (1979).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60427D4F051FECFA5B4A84F8BB.taxon	distribution	Distribution: Bermuda and from USA (North Carolina) to Brazil (Abrolhos and from Ceará to São Paulo) (Christoffersen 1979, 1998; Almeida et al. 2018 b; this study).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60427D4F051FECFA5B4A84F8BB.taxon	biology_ecology	Ecology: Among rocks, in coralline rocks with algae, in calcareous algae, reefs of Phragmatopoma sp., and in association with ascidians and sponges (e. g., Callyspongia sp., Ircinia sp., Hymeniacidon sp., Pseudoceratina sp., Xestospongia sp.); in heterosexual pairs; intertidal to 85 m (Christoffersen 1979; Anker et al. 2012).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B60427D4F051FECFA5B4A84F8BB.taxon	discussion	Remarks: Synalpheus minus is part of the S. brevicarpus complex, as mentioned above.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042404F381FECFF4F4D56FD73.taxon	materials_examined	Material examined: Pernambuco — Continental Shelf off Recife: 1 M, 07. ii. 2018, 8 ° 08 ′ 43.7 ′′ S 34 ° 34 ′ 22.6 ′′ W, 54.0 m depth, MOUFPE 21546; Recife: 2 M, 08 ° 09 ′ 7 ′′ S 34 ° 45 ′ 0 ′′ W, 31.5 m depth, MOUFPE 15389.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042404F381FECFF4F4D56FD73.taxon	description	Description: Coutière (1909), Dardeau (1984), Ríos & Duffy (2007), and Anker et al. (2012).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042404F381FECFF4F4D56FD73.taxon	distribution	Distribution: USA (Florida), Gulf of Mexico, Bahamas, Cuba, Mexico, Honduras, Panama, Puerto Rico, Virgin Islands, Curaçao, Barbados, and Brazil (Ceará and Pernambuco) (Anker et al. 2012 and references therein; Cházaro-Olvera et al. 2017; this study).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042404F381FECFF4F4D56FD73.taxon	biology_ecology	Ecology: Shallow reefs and marine substrates, in sponges [Lissodendoryx cf. strongylata van Soest, 1984, L. colombiensis, Agelas clathrodes (Schmidt, 1870), H. intestinalis, E. ferox, and A. crassa]; in heterosexual pairs; shallow waters to 80 m (Ríos & Duffy, 2007; Anker et al. 2012; Cházaro-Olvera et al. 2017; De Grave & Anker 2017).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042404F381FECFF4F4D56FD73.taxon	discussion	Remarks: S. pandionis was previously known from Brazil based on a single record from Ceará (Anker et al. 2012). Here, we extend its southern range in the western Atlantic.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042404F381FECFD0F4D31F9D8.taxon	materials_examined	Material examined: Pernambuco — Fernando de Noronha: 4 M, 1 OV, 2 F, Buraco do Inferno, 18. vi. 2019, 03 ° 48.968 ′ S 32 ° 23.577 ′ W, 13.0 – 15.0 m depth, in sponge, DZ / UFRGS 7073; 3 M, Ilha do Meio, 18. vi. 2019, 03 ° 49.015 ′ S 32 ° 23.549 ′ W, 12.0 m depth, in sponge, DZ / UFRGS 6705; 2 M, Ressureta, 19. vi. 2019, 03 ° 49.191 ′ S 32 ° 23.847 ′ W, 8.0 m depth, in sponge, DZ / UFRGS 7070; 2 M, Ponta da Sapata, 17. vi. 2019, 03 ° 51.892 ′ S 32 ° 27.965 ′ W, 8.0 m depth, in sponge, DZ / UFRGS 6707; Continental Shelf off Recife: 1 M, 10. v. 2018, 08 ° 21 ′ 34.9 ′′ S 34 ° 41 ′ 53.3 ′′ W, 50.8 m depth, in sponge, MOUFPE 21794; 1 F, same data as MOUFPE 21794, MOUFPE 21793.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042404F381FECFD0F4D31F9D8.taxon	description	Description: Macdonald & Duffy (2006), Ríos & Duffy (2007), and Anker & Pachelle (2014).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042404F381FECFD0F4D31F9D8.taxon	distribution	Distribution: Belize, Panama, and Brazil (Fernando de Noronha, Ceará, and Pernambuco) (Macdonald & Duffy 2006; Ríos & Duffy, 2007; Anker & Pachelle 2014; this study).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042404F381FECFD0F4D31F9D8.taxon	biology_ecology	Ecology: Obligatory symbiont of sponges (A. dispar, H. cf. caerulea, and unidentified sponge species); in heterosexual pairs; shallow waters to 50.8 m (Macdonald & Duffy 2006; Ríos & Duffy, 2007; Anker & Pachelle 2014, as S. cf. ruetzleri; this study). Sampled at Fernando de Noronha (DZ / UFRGS 6705, 6707, 7070, 7073) and continental shelf off Recife (MOUFPE 21793, 21794) in association with sponges (unidentified).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042404F381FECFD0F4D31F9D8.taxon	discussion	Remarks: Synalpheus ruetzleri is part of the S. brooksi complex (Macdonald & Duffy 2006) and, as described by Macdonald & Duffy (2006), exhibits an extensive morphological variation, complicating its identification within the complex. The first record of the species from Brazil was provided by Anker & Pachelle (2014), from Ceará, where the material was identified as S. cf. ruetzleri due to differences from the type material (for more details, see Remarks of S. cf. ruetzleri in Anker & Pachelle 2014). Our material agrees with the description provided by Macdonald & Duffy (2006), except for one male (DZ / UFRGS 6710) that exhibited four articles in the carpus of the second pair of pereiopods (vs. five articles in the holotype) (see Macdonald & Duffy 2006, fig. 11 G). The present study expands the known range of the species in the southwestern Atlantic, as well as its bathymetric distribution, from less than 20 m (Anker & Pachelle 2014) to 50.8 m.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042404F391FECF9AC4FCAFC1B.taxon	materials_examined	Material examined: Pernambuco — Fernando de Noronha: 1 M, Buraco do Inferno, 26. vi. 2022, 03 ° 48.968 ′ S 32 ° 23.577 ′ W, 12.0 m depth, in sponge, DZ / UFRGS 7033; 1 F, Ilha do Meio, 26. vi. 2022, 03 ° 49.015 ′ S 32 ° 23.549 ′ W, 11.0 m depth, in sponge, DZ / UFRGS 7039; Continental Shelf off Recife: 3 M, 1 OV, 2 F, 07. ii. 2018, 8 ° 08 ′ 43.7 ′′ S 34 ° 34 ′ 22.6 ′′ W, 54.0 m depth, MOUFPE 21785; 1 M, 1 OV, 07. ii. 2018, 8 ° 09 ′ 06.8 ′′ S 34 ° 34 ′ 28.4 ′′ W, 53.0 m depth, MOUFPE 21786; 1 M, 27. ii. 2018, 8 ° 13 ′ 33.0 ′′ S 34 ° 37 ′ 40.3 ′′ W, 50.6 m depth, in sponge, MOUFPE 21540; 1 F, 10. v. 2018, 08 ° 21 ′ 34.9 ′′ S 34 ° 41 ′ 53.3 ′′ W, 50.8 m depth, in sponge, MOUFPE 21795; 1 F, 10. v. 2018, 08 ° 23 ′ 04.3 ′′ S 34 ° 40 ′ 07 ′′ W, 80.0 m depth, in sediment, MOUFPE 21789; 1 M, same data as MOUFPE 21789, in sponge, MOUFPE 21829; 1 M, 1 NI, same data as MOUFPE 21789, in sponge, MOUFPE 21827; 1 OV, same data as MOUFPE 21789, in sponge, MOUFPE 21828; 1 M, 1 F, same data as MOUFPE 21789, in sponge, MOUFPE 21819; 1 M, same data as MOUFPE 21789, in sponge, MOUFPE 21832; 1 M, same data as MOUFPE 21789, in sponge, MOUFPE 21838; 1 M, 1 F, same data as MOUFPE 21789, in sponge, MOUFPE 21823; 1 OV, same data as MOUFPE 21789, in sponge, MOUFPE 21839; 1 M, same data as MOUFPE 21789, in sponge, MOUFPE 21840; 3 M, 1 F, same data as MOUFPE 21789, in sponge, MOUFPE 21835; 1 M, same data as MOUFPE 21789, in sponge, MOUFPE 21846; 1 M, same data as MOUFPE 21789, in sponge, MOUFPE 21850; 1 M, 1 F, same data as MOUFPE 21789, in sponge, MOUFPE 21841; 1 F, same data as MOUFPE 21789, in sponge, MOUFPE 21843; 1 M, 1 F, same data as MOUFPE 21789, in sponge, MOUFPE 21845.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042404F391FECF9AC4FCAFC1B.taxon	description	Description: Coutière (1909), Dardeau (1984), and Ríos & Duffy (2007).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042404F391FECF9AC4FCAFC1B.taxon	distribution	Distribution: USA (Florida), Caribbean Sea, and Brazil (Rocas Atoll, Almirante Saldanha Seamounts, Trindade Island, and from Pernambuco to Bahia) (Christoffersen 1979; Ríos & Duffy, 2007; Anker et al. 2016).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042404F391FECF9AC4FCAFC1B.taxon	biology_ecology	Ecology: Coral reefs or on sea bottom with abundance of perforated rocks and calcareous algae; in association with sponges (e. g., Agelas sp., Hyattella sp., Hymeniacidon sp., and Lissodendoryx sp.) (Ríos & Duffy, 2007); in heterosexual pairs; more commonly from 1 – 20 m, with records at 80 m (this study) and 105 m (Anker et al. 2012, 2016).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042404F391FECF9AC4FCAFC1B.taxon	discussion	Remarks: Synalpheus sanctithomae is morphologically similar to S. mcclendoni Coutière, 1910, differing from the latter species by the fingers of major chela being not curved (vs. curved mesially in S. mcclendoni) (for comparison, see Coutière, 1909, fig. 35 K, for S. sanctithomae, and Dardeau 1984, fig. 38 L, for S. mcclendoni) (Anker et al. 2012). The record of S. sanctithomae by Bezerra & Coelho (2006) from Ceará has been reassigned to S. townsendi (Anker et al. 2012). Hultgren et al. (2010) documented morphological variations in the species, including the number of setae on distal margin of telson (ranging from 2 to 7) and the presence of a row of setae on the major chela dactyl (vs. major chela dactyl without row of setae) (see Coutière, 1909, fig. 35 K). A male specimen from the continental shelf off Recife (MOUFPE 21850) examined in this study fits the diagnostic features in the description, but exhibited three pairs of dorsal spiniform setae on the telson (vs. two pair of dorsal spiniform setae) (see Coutière, 1909, fig. 35 T).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042414F391FECFBEB4F23F8E9.taxon	materials_examined	Material examined: Pernambuco — Continental Shelf off Recife: 1 M, 10. v. 2018, 08 ° 21 ′ 34.9 ′′ S 34 ° 41 ′ 53.3 ′′ W, 50.8 m depth, in sponge, MOUFPE 21790; Brazil, Bahia — Porto Seguro: 1 M, Praia de Mutá, 25. ix. 2011, associated with Millepora alcicornis Linnaeus, 1785, MOUFPE 21865.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042414F391FECFBEB4F23F8E9.taxon	description	Description: Dardeau (1984) and Anker et al. (2012).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042414F391FECFBEB4F23F8E9.taxon	distribution	Distribution: Bermuda, USA (Florida), Gulf of Mexico, Caribbean Sea, and Brazil (from Pernambuco to São Paulo) (Pequegnat & Ray 1974; Dardeau 1986; Duffy 1992; Christoffersen 1998; Anker et al. 2012).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042414F391FECFBEB4F23F8E9.taxon	biology_ecology	Ecology: Shallow coral reefs and adjacent areas; coral and rock cavities, mangroves with perforated trunks, on the coral M. alcicornis; in heterosexual pairs; shallow waters to 50.8 m (Schmitt 1924; Dardeau 1986; Anker et al. 2012; Santos et al. 2012). Sampled in association with sponge (this study).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042414F391FECFBEB4F23F8E9.taxon	discussion	Remarks: Synalpheus scaphoceris is one of the most common species found on coral reefs in the Caribbean, but it is rarely encountered along the Brazilian coast (Anker et al. 2012). The species can be differentiated from the morphologically similar S. townsendi by presenting several red chromatophores distributed across its body (see Anker et al. 2012, fig. 44) (vs. restricted to the region between the eyes in S. townsendi; see Anker et al. 2012, fig. 46), by the ventral process of the rostrum being strongly produced (see Dardeau 1986, fig. 3 C) (vs. short in S. townsendi; see Hermoso-Salazar et al. 2005, fig. 1 B), by the absence of a distodorsal tooth on the major chela (see Dardeau 1986, fig. 2 G) (vs. major chela with a strong, sharp, distodorsal tooth in S. townsendi) (Dardeau 1986; Hermoso-Salazar et al. 2005; Anker et al. 2012). The present study extends the bathymetric distribution of the species from 20 (Anker et al. 2012) to 50.8 m, and provides the first record of association of. S. scaphoceris with a sponge.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042414F3A1FECF8B74D19FE5B.taxon	materials_examined	Material examined: Rio Grande do Norte — São Pedro e São Paulo Archipelago: 1 F, 30 m depth, MOUFPE 13565; Pernambuco — Ilha de Itamaracá: 1 M, 1 F, Ilha de Itamaracá, St. 01, MOUFPE 8897.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042414F3A1FECF8B74D19FE5B.taxon	description	Description: Anker & Pachelle (2014).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042414F3A1FECF8B74D19FE5B.taxon	distribution	Distribution: Brazil (São Pedro e São Paulo Archipelago, Rio Grande do Norte, Pernambuco, Rio de Janeiro, São Paulo, and Santa Catarina) (Anker & Pachelle 2014; this study).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042414F3A1FECF8B74D19FE5B.taxon	biology_ecology	Ecology: Dwelling in pier growth or in crevices of polychaete reefs, on Schizoporella sp. bryozoan colonies; in heterosexual pairs; shallow waters to 45 m (Anker & Pachelle 2014; Almeida et al. 2018 b).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042414F3A1FECF8B74D19FE5B.taxon	discussion	Remarks: Synalpheus tenuispina is endemic to the Brazilian coast. Caribbean records (e. g., Abele 1976; Martínez-Iglesias et al. 1993, 1996) have been reassigned to Synalpheus cf. africanus (Anker & Pachelle 2014). This study extends the northern known range of the species.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042424F3B1FECFE264C17FD07.taxon	materials_examined	Material examined: Maranhão — Turiaçu: 1 F, Nordeste Expedition II, St. 111 / 112, MOUFPE 12510; Ceará — Camocim: 1 F, Almirante Saldanha Expedition, St. 1722, 29. x. 1967, 02 ° 13.5 ′ S 40 ° 43.5 ′ W, 53.0 m depth, MOUFPE 8948; Pernambuco — Fernando de Noronha: 1 F, Buraco do Inferno, 26. vi. 2022, 03 ° 48.968 ′ S 32 ° 23.577 ′ W, 12.0 m depth, in sponge, DZ / UFRGS 7034; 1 OV, Laje Dois Irmãos, 30. vi. 2022, 03 ° 51.859 ′ S 32 ° 27.934 ′ W, 17.0 m depth, in sponge, DZ / UFRGS 7047; 1 F, Ilha do Meio, 18. vi. 2019, 03 ° 49.015 ′ S 32 ° 23.549 ′ W, 12.0 m depth, in sponge, DZ / UFRGS 7072; 1 F, Ressureta, 19. vi. 2019, 03 ° 49.191 ′ S 32 ° 23.847 ′ W, 8.0 m depth, in sponge, DZ / UFRGS 7071; Continental Shelf off Recife: 1 M, 07. ii. 2018, 8 ° 08 ′ 51.5 ′′ S 34 ° 34 ′ 08.0 ′′ W, 65.0 m depth, in sponge, MOUFPE 21797; 1 OV, same data as MOUFPE 21797, MOUFPE 21798; 1 M, same data as MOUFPE 21797, MOUFPE 21799; 1 M, same data as MOUFPE 21797, MOUFPE 21800; 1 M, same data as MOUFPE 21797, MOUFPE 21801; 1 NI, same data as MOUFPE 21797, MOUFPE 21802; 1 M, same data as MOUFPE 21797, MOUFPE 21804; 1 M, same data as MOUFPE 21797, MOUFPE 21805; 1 M, same data as MOUFPE 21797, MOUFPE 21806; 1 M, same data as MOUFPE 21797, MOUFPE 21807; 1 OV, same data as MOUFPE 21797, MOUFPE 21809; 1 OV, 10. v. 2018, 08 ° 21 ′ 34.9 ′′ S 34 ° 41 ′ 53.3 ′′ W, 50.8 m depth, in sponge, MOUFPE 21796; 1 F, same data as MOUFPE 21796, MOUFPE 21792; 1 OV, 27. ii. 2018, 8 ° 13 ′ 33.0 ′′ S 34 ° 37 ′ 40.3 ′′ W, 50.6 m depth, in sponge, MOUFPE 21536; 1 M, 27. ii. 2018, 8 ° 13 ′ 52.1 ′′ S 34 ° 37 ′ 39.1 ′′ W, 50.8 m depth, in sponge, MOUFPE 21543; 1 F, 27. ii. 2018, 8 ° 13 ′ 52.1 ′′ S 34 ° 37 ′ 41.2 ′′ W, 51.8 m depth, in sponge, MOUFPE 21538; 1 M, same data as MOUFPE 21538, in sponge, MOUFPE 21539; 1 M, 1 F, same data as MOUFPE 21538, in sponge, MOUFPE 21535; 1 F, 27. ii. 2018, 8 ° 13 ′ 52.1 ′′ S 34 ° 37 ′ 42.7 ′′ W, 50.0 m depth, in sponge, DZ / UFRGS 7060; 1 M, same data as DZ / UFRGS 7060, MOUFPE 21568; 1 OV, same data as DZ / UFRGS 7060, MOUFPE 21576; 1 F, 10. v. 2018, 08 ° 23 ′ 04.3 ′′ S 34 ° 40 ′ 07 ′′ W, 80.0 m depth, in sponge, MOUFPE 21830; 1 M, 1 OV, same data as MOUFPE 21830, MOUFPE 21821; 1 NI, same data as MOUFPE 21830, MOUFPE 21820; 1 M, 1 OV, same data as MOUFPE 21830, MOUFPE 21847; 1 F, same data as MOUFPE 21830, MOUFPE 21831; 1 M, 1 OV, same data as MOUFPE 21830, MOUFPE 21848; 1 OV, same data as MOUFPE 21830, MOUFPE 21817; 1 M, 1 OV, same data as MOUFPE 21830, MOUFPE 21852; 1 OV, same data as MOUFPE 21830, MOUFPE 21822; 1 OV, same data as MOUFPE 21830, MOUFPE 21824; 1 OV, same data as MOUFPE 21830, MOUFPE 21856; 1 F, same data as MOUFPE 21830, MOUFPE 21836; 1 F, same data as MOUFPE 21830, MOUFPE 21844; 1 M, same data as MOUFPE 21830, MOUFPE 21837; 1 M, 1 F, 1 NI, same data as MOUFPE 21830, MOUFPE 21833; 1 M, same data as MOUFPE 21830, MOUFPE 21851; 1 M, same data as MOUFPE 21830, MOUFPE 21853; 1 M, same data as MOUFPE 21830, MOUFPE 21854; 2 M, same data as MOUFPE 21830, MOUFPE 21834; 2 M, same data as MOUFPE 21830, MOUFPE 21849; 1 M, same data as MOUFPE 21830, in sediment, MOUFPE 21787; 1 F, 07. ii. 2018, 8 ° 08 ′ 43.7 ′′ S 34 ° 34 ′ 22.6 ′′ W, 54.0 m depth, in coral rubble, MOUFPE 21569; 1 F, 27. ii. 2018, 8 ° 13 ′ 33.0 ′′ S 34 ° 37 ′ 40.3 ′′ W, 50.6 m depth, MOUFPE 21562; 1 F, 27. ii. 2018, 8 ° 13 ′ 25.4 ′′ S 34 ° 37 ′ 43.2 ′′ W, 51.0 m depth, MOUFPE 21573; 1 M, 27. ii. 2018, 8 ° 13 ′ 52.1 ′′ S 34 ° 37 ′ 39.1 ′′ W, 50.8 m depth, MOUFPE 21574; 1 F, 27. ii. 2018, 8 ° 13 ′ 52.1 ′′ S 34 ° 37 ′ 41.2 ′′ W, 51.8 m depth, MOUFPE 21551; 1 M, same data as MOUFPE 21551, MOUFPE 21552; 1 F, same data as MOUFPE 21551, MOUFPE 21553; 1 F, same data as MOUFPE 21551, MOUFPE 21554; 1 F, same data as MOUFPE 21551, MOUFPE 21556; 1 M, same data as MOUFPE 21551, MOUFPE 21557; 1 M, same data as MOUFPE 21551, MOUFPE 21558; 1 M, same data as MOUFPE 21551, MOUFPE 21561; 1 F, same data as MOUFPE 21551, MOUFPE 21565; 1 M, same data as MOUFPE 21551, MOUFPE 21570; 1 M, same data as MOUFPE 21551, MOUFPE 21571; 1 M, same data as MOUFPE 21551, MOUFPE 21572; 1 M, same data as MOUFPE 21551, MOUFPE 21575; Recife: 1 M, 08 ° 09 ′ 7 ′′ S 34 ° 45 ′ 0 ′′ W, 31.5 m depth, MOUFPE 15392; 1 M, same data as MOUFPE 15392, MOUFPE 15389; Bahia — Abrolhos: 2 M, Ilha de Santa Bárbara, 31. viii. 2013, in dead coral, MOUFPE 21866; 1 M, 1 OV, Ilha de Santa Bárbara, 31. viii. 2013, in sponge, MOUFPE 21867.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042424F3B1FECFE264C17FD07.taxon	description	Description: Coutière (1909), Williams (1984), and Anker et al. (2012).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042424F3B1FECFE264C17FD07.taxon	distribution	Distribution: Bermuda, USA (from North Carolina to Florida), Gulf of Mexico, Honduras, Panama, Jamaica, Curaçao, and Barbados to Brazil (Rocas Atoll, Fernando de Noronha, Trindade & Martin Vaz Archipelago, Maranhão, and from Ceará to São Paulo) (Hermoso-Salazar et al. 2005; Anker et al. 2012, 2016; Soledade et al. 2015; Almeida et al. 2018 b; this study).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042424F3B1FECFE264C17FD07.taxon	biology_ecology	Ecology: Reef areas with abundance of sponges, Phragmatopoma sp., reef cavities, or dead corals (e. g. Oculina sp., Porites sp., Siderastrea sp., Mussismilia sp.); calcareous algae and ascidians, in mangroves, worm-perforated wood, and sponges; in heterosexual pairs; shallow waters to 102 m (Rouse 1970; Gore et al. 1978; Rodríguez 1980; Reed et al. 1982; Duffy 1992; Anker et al. 2012; 2016). Sampled herein in sediment, coral rubble, dead coral and sponges.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042424F3B1FECFE264C17FD07.taxon	discussion	Remarks: Synalpheus townsendi is a common and widely distributed species throughout the western Atlantic, with numerous records along the Brazilian coast (Anker et al. 2012). One specimen collected from the continental shelf off Recife carried a rhizocephalan pleonal parasite (MOUFPE 21821). The material from Parque Estadual Marinho da Pedra da Risca do Meio, Fortaleza, previously reported by Bezerra & Coelho (2006), has been reidentified as S. brooksi (see S. brooksi section).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042434F3B1FECFC9A4C8EFA37.taxon	materials_examined	Material examined: Pernambuco — Continental Shelf off Recife: 1 M, 07. ii. 2018, 8 ° 08 ′ 51.5 ′′ S 34 ° 34 ′ 08.0 ′′ W, 65.0 m depth, in sponge, MOUFPE 21808; Sergipe — 2 M, 3 OV, Plataforma Pcb 4 Face Externa Fora Fundo, 01. xi. 2000, MOUFPE 15790; 1 M, Plataforma Pcm 11 Pós Face Externa Pé: Fora Superfície Externa, MOUFPE 15791; 1 OV, Plataforma Pd 02 Face Externa Terra Meio, 30. x. 2000, MOUFPE 15792; 1 M, Plataforma Pcb 4 Face Externa Terra Superficie, 01. xi. 2000, MOUFPE 15793; 1 M, 1 OV, Plataforma Pcm 5 Pós: Face Externa Pé: Terra Superfície, MOUFPE 15794.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042434F3B1FECFC9A4C8EFA37.taxon	description	Description: Mantelatto et al. (2023).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042434F3B1FECFC9A4C8EFA37.taxon	distribution	Distribution: Brazil (Pernambuco, Sergipe, Bahia and São Paulo) (Mantelatto et al. 2023; this study).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042434F3B1FECFC9A4C8EFA37.taxon	biology_ecology	Ecology: Under rocks, dead coral rubble and on dead parts of M. alcicornis in association with the bryozoan Schizoporella errata (Waters, 1878) and the sponge Amphimedon viridis Duchassaing & Michelotti, 1864; 2 65 m (Almeida et al. 2012, as S. cf. brevicarpus; 2018, as S. cf. brevicarpus (green / blue chela); Santos et al. 2012, as S. cf. brevicarpus; Mantelatto et al. 2023; this study).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042434F3B1FECFC9A4C8EFA37.taxon	discussion	Remarks: Synalpheus ubatuba belongs to the S. brevicarpus complex (Mantelatto et al. 2023; see remarks in the S. cf. brevicarpus section). The occurrence of S. ubatuba in the Northeast region has been confirmed in localities in southern Bahia (Mantelatto et al. 2023). The present study expands the known bathymetric distribution for the species from 8 (Mantelatto et al. 2023) to 65 m.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042434F3C1FECF9CA4F58F9DB.taxon	materials_examined	Material examined: Pernambuco — Goiana: 1 M, 1 OV, Praia de Catuama, 20. i. 2023, 7 ° 39 ′ 18.6 ′′ S 34 ° 49 ′ 28.1 ′′ W, 1.5 m depth, in sponge, MOUFPE 21811; Cabo de Santo Agostinho: 7 M, 2 OV, 1 F, Baía de Suape, 15. viii. 2022, 8 ° 21 ′ 54 ′′ S 34 ° 56 ′ 50 ′′ W, 3.5 m depth, in sponge, MOUFPE 21784; 1 M, 1 OV, Baía de Suape, 16. viii. 2019, 8 ° 21 ′ 54 ′′ S 34 ° 56 ′ 50 ′′ W, 3.5 m depth, associated with E. dendroides, MOUFPE 21511; 1 M, 1 OV, same data as MOUFPE 21511, in unindentified sponge, MOUFPE 21512; 4 M, 1 OV, same data as MOUFPE 21511, MOUFPE 21517; 1 M, 1 OV, same data as MOUFPE 21511, MOUFPE 21514; 5 M, 1 OV, same data as MOUFPE 21511, MOUFPE 21518; 2 M, 1 OV, same data as MOUFPE 21511, in unindentifed sponge, MOUFPE 21520; 1 M, 1 OV, same data as MOUFPE 21511, in unindentified sponge, MOUFPE 21516; 3 M, same data as MOUFPE 21511, in unindentified sponge, MOUFPE 21515; 3 M, 1 OV, same data as MOUFPE 21511, in unindentified sponge, MOUFPE 21519; 3 M, 1 OV, Baía de Suape, 26. x. 2018, 8 ° 21 ′ 54 ′′ S 34 ° 56 ′ 50 ′′ W, 3.5 m depth, associated with E. dendroides, MOUFPE 21593; 6 M, same data as MOUFPE 21593, MOUFPE 21588; 1 OV, same data as MOUFPE 21593, MOUFPE 21582; 1 M, 1 OV, same data as MOUFPE 21593, MOUFPE 21529; 1 M, 1 OV, same data as MOUFPE 21593, MOUFPE 21586; 1 M, 1 OV, same data as MOUFPE 21593, MOUFPE 21591; 1 M, same data as MOUFPE 21593, MOUFPE 21527; 1 OV, same data as MOUFPE 21593, MOUFPE 21531; 2 OV, same data as MOUFPE 21593, MOUFPE 21524; 1 M, 1 OV, same data as MOUFPE 21593, MOUFPE 21592; 1 M, same data as MOUFPE 21593, MOUFPE 21533; 1 M, 1 OV, same data as MOUFPE 21593, MOUFPE 21604; 3 M, 3 OV, same data as MOUFPE 21593, in unindentided sponge, MOUFPE 21862; 1 M, 2 OV, Baía de Suape, 21. iii. 2019, 8 ° 21 ′ 54 ′′ S 34 ° 56 ′ 50 ′′ W, 3.5 m depth, associated with E. dendroides, MOUFPE 21578; 2 M, 1 OV, same data as MOUFPE 21578, MOUFPE 21580; 1 M, 1 OV, same data as MOUFPE 21578, MOUFPE 21525; 2 M, 2 OV, same data as MOUFPE 21578, MOUFPE 21534; 1 M, 1 OV, same data as MOUFPE 21578, MOUFPE 21532; 1 M, 1 OV, same data as MOUFPE 21578, MOUFPE 21590; 1 M, 2 F, Praia do Paraíso, 23. ix. 2022, 8 ° 21 ′ 54 ′′ S 34 ° 56 ′ 50 ′′ W, associated with E. dendroides, DZ / UFRGS 7048; Tamandaré: 1 M, 1 OV, Praia de Carneiros, 06. vi. 2019, 8 ° 41 ′ 32 ′′ S 35 ° 4 ′ 25 ′′ W, 2.0 m depth, in sponge, MOUFPE 21598; 27 M, 13 OV, 2 F, Praia de Carneiros, 22. iii. 2019, 8 ° 41 ′ 32 ′′ S 35 ° 4 ′ 25 ′′ W, 3.5 m depth, associated with E. dendroides, MOUFPE 21599 (genetic voucher, genbank access PV 273118); 2 M, 1 OV, Praia de Carneiros, 20. vii. 2019, 8 ° 41 ′ 32 ′′ S 35 ° 4 ′ 25 ′′ W, 3.5 m depth, associated with E. dendroides, MOUFPE 21606; 2 M, 1 OV, same data as MOUFPE 21606, MOUFPE 21607; 1 M, 1 OV, same data as MOUFPE 21606, MOUFPE 21605; 1 M, 1 OV, same data as MOUFPE 21606, MOUFPE 21608; 1 M, 1 OV, same data as MOUFPE 21606, MOUFPE 21609; 1 F, same data as MOUFPE 21606, MOUFPE 21616; 1 OV, same data as MOUFPE 21606, MOUFPE 21624; 2 M, 1 OV, same data as MOUFPE 21606, MOUFPE 21623; 1 M, 1 F, same data as MOUFPE 21606, MOUFPE 21625; 1 M, 1 OV, same data as MOUFPE 21606, MOUFPE 21613; 1 M, 1 OV, same data as MOUFPE 21606, MOUFPE 21614; 2 M, same data as MOUFPE 21606, MOUFPE 21615; 2 M, same data as MOUFPE 21606, MOUFPE 21617; 1 OV, same data as MOUFPE 21606, MOUFPE 21810; 3 M, 1 OV, same data as MOUFPE 21606, MOUFPE 21618.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042434F3C1FECF9CA4F58F9DB.taxon	description	Description: Ríos & Duffy (2007), Almeida et al. (2012), and Anker et al. (2012).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042434F3C1FECF9CA4F58F9DB.taxon	distribution	Distribution: Belize, Panama, Jamaica, Dominican Republic, Saint Martin, Barbados, Curaçao, and Brazil (Pernambuco, Alagoas, Sergipe and Bahia) (Hultgren et al. 2011; Almeida et al. 2012; Anker & Pachelle 2014; Barros-Alves et al. 2015).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042434F3C1FECF9CA4F58F9DB.taxon	biology_ecology	Ecology: In shallow reefs; associated with rubble and seagrass banks with abundance of sponges, and substrates covered by bryozoans; obligate symbiont of sponges (e. g., Hymeniacidon sp., Hyattella sp., Lissodendoryx sp., Xestospongia sp.); in heterosexual pairs (see Remarks below); shallow waters to 52 m (Ríos & Duffy, 2007; Anker et al. 2012; Anker & Pachelle 2014).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042434F3C1FECF9CA4F58F9DB.taxon	discussion	Remarks: Anker et al. (2012) stated that S. ul forms heterosexual pairs; however, groups ranging from 2 – 6 to 42 individuals, with varying proportions of males and females, were observed in the same host sponge (see Discussion section for details). Some organisms were parasitized in the gill chamber by bopyrid isopods (1 OV, MOUFPE 21518; 1 M, MOUFPE 21525; 1 OV, MOUFPE 21862). Morphological variations were observed in our material. In some specimens (1 M, MOUFPE 21529; 6 M, MOUFPE 21599), the mesial spiniform setae on the posterior margin of the telson were slightly longer and broader than the lateral, as previously reported by Hultgren et al. (2010). Herein, we provide the first 16 S gene sequences for the species in the southwestern Atlantic. Our sequences are identical to sequences of specimens collected in the Caribbean Sea (Barbados and Panama) (Fig. 19) (detailed in Discussion section).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042444F3D1FECF9A64ED5FD07.taxon	materials_examined	Material examined: Pernambuco — Continental Shelf off Recife: 1 OV, 27. ii. 2018, 8 ° 13 ′ 52.1 ′′ S 34 ° 37 ′ 41.2 ′′ W, 51.8 m depth, in sponge, DZ / UFRGS 7062; 1 M, same data as DZ / UFRGS 7062, MOUFPE 21547; 1 M, 10. v. 2018, 08 ° 23 ′ 04.3 ′′ S 34 ° 40 ′ 07 ′′ W, 80.0 m depth, in sponge, DZ / UFRGS 7061; 1 M, same data as DZ / UFRGS 7061, in sediment, MOUFPE 21788; 1 M, 07. ii. 2018, 8 ° 08 ′ 43.7 ′′ S 34 ° 34 ′ 22.6 ′′ W, 54.0 m depth, in rhodoliths, MOUFPE 21563; 1 M, 07. ii. 2018, 8 ° 08 ′ 44.2 ′′ S 34 ° 34 ′ 23.2 ′′ W, 55.0 m depth, MOUFPE 21545; 1 OV, same data as MOUFPE 21545, MOUFPE 21548; 1 M, 27. ii. 2018, 8 ° 13 ′ 52.1 ′′ S 34 ° 37 ′ 42.7 ′′ W, 50.0 m depth, MOUFPE 21566; 1 M, same data as MOUFPE 21566, MOUFPE 21567; 1 F, same data as MOUFPE 21566, MOUFPE 21560; 1 M, 27. ii. 2018, 8 ° 13 ′ 33.0 ′′ S 34 ° 37 ′ 40.3 ’’ W, 50.6 m depth, MOUFPE 21577; 1 OV, 27. ii. 2018, 8 ° 13 ′ 25.4 ′′ S 34 ° 37 ′ 43.2 ′′ W, 51.0 m depth, MOUFPE 21544; 1 M, 27. ii. 2018, 8 ° 13 ′ 52.1 ′′ S 34 ° 37 ′ 39.1 ′′ W, 50.8 m depth, MOUFPE 21550; Tamandaré: 2 M, xii. 1972, MOUFPE 8864; Bahia — Camamu: 1 M, Baía de Camamu, MOUFPE 21864.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042444F3D1FECF9A64ED5FD07.taxon	description	Description: Ríos & Duffy (2007) and Anker et al. (2012).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042444F3D1FECF9A64ED5FD07.taxon	distribution	Distribution: Gulf of Mexico, Belize, Panama, Jamaica, and Brazil (Ceará, Pernambuco, and Bahia) (Ríos & Duffy, 2007; Anker et al. 2012; Anker & Pachelle 2014; this study).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042444F3D1FECF9A64ED5FD07.taxon	biology_ecology	Ecology: In shallow reefs and nearby areas with abundance of gravel and sponges; nearby mangroves and seagrass banks; symbiont of Lissodendoryx cf. strongylata, L. colombiensis, H. caerulea, and C. podatypa; in heterosexual pairs; 1 – 80 m (Ríos & Duffy, 2007; Anker et al. 2012; this study). Material from the continental shelf off Recife sampled in rhodoliths, sediment and sponges.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042444F3D1FECF9A64ED5FD07.taxon	discussion	Remarks: Synalpheus yano is characterized by a square to broadly rounded orbital teeth and the absence of a scaphocerite blade, which is reduced in other members of the group (Ríos & Duffy, 2007; Anker et al. 2012). Morphological variations have been previously reported in S. yano, particularly in males sampled in Panama and analyzed by Anker et al. (2012), where the orbital teeth were more triangular. The rostrum was missing in one specimen analyzed in this study (1 M, MOUFPE 8864). Synalpheus yano has been reported on the Brazilian coast only from Ceará. Herein, we expand the southern known range of the species in the western Atlantic as well as its bathymetric distribution from 3 (Anker et al. 2012) to 80 m.	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
26013B6042464F3E1FECFF074A91FA8F.taxon	materials_examined	Of the 27 species that have been recorded from Northeast Brazil, 20 were analyzed in the present study. We have not examined material of S. cf. africanus, S. bousfieldi, S. filidigitus, S. longicarpus, S. maxillispinus, S. paraneptunus and S. rathbunae (Table 1). The present study provides six new records for the southwestern Atlantic (S. barahonensis, S. belizensis, S. brevidactylus, S. corallinus, S. hoetjesi, and S. kensleyi) and 13 range extensions / new records from Brazil (S. agelas, S. androsi, S. antillensis, S. dardeaui, S. fritzmuelleri, S. hemphilli, S. herricki, S. pandionis, S. ruetzleri, S. tenuispina, S. townsendi, S. ubatuba, and S. yano) (Figs. 20, 21), increasing the known diversity of Synalpheus in the study area, excluding the four doubtful records (see below), to 29 species. Most of the new records in this study involve species collected from calcareous substrates on the outer continental shelf off Recife, Pernambuco (S. androsi, S. barahonensis, S. belizensis, S. brevidactylus, S. corallinus, S. herricki, S. kensleyi, S. pandionis, S. ruetzleri, and S. yano), the majority of which are sponge-associated. Sampling in underexplored areas and substrates, particularly on the continental shelf, often yields new records, extensions of known bathymetric distributions, as demonstrated in this study, and the discovery of new taxa (e. g., Soledade et al. 2019). Additionally, new records for species inhabiting shallow coastal waters (S. dardeaui, S. hoetjesi, S. kensleyi, S. pandionis, S. tenuispina, and S. yano) were also documented. These findings are attributed to the scarcity of studies focusing on the genus in the region and the taxonomic challenges associated with identifying certain species, besides the employment of advanced sampling techniques such as artificial refuge structures (ARS), diving, and dredging (Hultgren et al. 2010; Anker et al. 2012, 2016). With the addition of six new records from the southwestern Atlantic and excluding the misidentifications and doubtful records discussed below, the number of Synalpheus species currently known from the Brazilian coast is 31 (Table 1). Sequences of the 16 S gene for S. barahonensis, S. hoetjesi, and S. ul were compared with other Synalpheus sequences available in GenBank to confirm their identification (Fig. 19). The sequence for S. barahonensis represents the first of this gene to be deposited in GenBank, rendering comparisons with other populations unfeasible at the moment. Conversely, the 16 S sequences for S. hoetjesi and S. ul are the first reported from the southwestern Atlantic. As noted earlier, the sequences of S. ul specimens from Brazil (PE) were found to be identical to those from the southern Caribbean (Barbados and Panama), suggesting recent connectivity between Brazil and the Caribbean Sea (Fig. 19). In the case of S. hoetjesi, although the two sequences from Praia dos Carneiros (S. hoetjesi – Brazil, PE) clustered with those from the Caribbean (Panama, Barbados, and Curaçao) in a well-supported clade, a subdivision within the clade was observed. This subdivision separated the Brazilian specimens from their Caribbean counterparts into two distinct lineages. Furthermore, a genetic difference of 0.5 % between these lineages was detected, suggesting small genetic variations between S. hoetjesi populations (Kimura & Weiss 1964; Avise 2000).	en	Paixão, Pedro Henrique, Terossi, Mariana, Pasinatto, Karmine, Bochini, Gabriel Lucas, Almeida, Alexandre Oliveira (2025): Shrimps of the genus Synalpheus Spence Bate, 1888 (Decapoda: Alpheidae) from Northeast Brazil region. Zootaxa 5666 (1): 1-52, DOI: 10.11646/zootaxa.5666.1.1, URL: http://dx.doi.org/10.11646/zootaxa.5360.3.8
