taxonID	type	description	language	source
03BC114A5D150123FF451012FE2AFA6C.taxon	materials_examined	Material Examined. Brazil. Alagoas: 1 male (CL 11.76 mm) DZUFRJ 3881 [holotype]: rio São Francisco, 29 Jan. 1995, collector: Matos, F. J. P.; 1 female (CL 11.39 mm) DZUFRJ 3880 [paratype]: riacho Marau — tributary of the rio São Francisco, Brazil, 23 May 1992, collector: Ostrovski, F.; 2 males (CL 15.45 mm and 11.58 mm) DZUFRJ 3882 [paratypes]: rio São Francisco, 21 May 1992, collector: Matos, F. J. P.; 13 males (CL 7.2 – 9.97 mm) DZUFRJ 2257 [paratypes]: rio São Francisco, Xingó, 29 Jan. 1995, collector: Matos, F. J. P.; 4 males (CL 08.21 – 11.20 mm) DZUFRJ 2660: rio São Francisco, 29 Jan. 1995, collector: Matos, F. J. P.	en	Cardim, Robert Wagner Dos Santos, Mota, Thaís Arrais, Carvalho, Fabrício Lopes (2025): Taxonomic assessment of the shrimp Macrobrachium denticulatum Ostrovski, da Fonseca & da Silva-Ferreira, 1996 (Decapoda: Palaemonidae) using molecular and morphological data: a comparison with M. olfersii (Wiegmann, 1836). Zootaxa 5631 (3): 475-494, DOI: 10.11646/zootaxa.5631.3.3, URL: https://doi.org/10.11646/zootaxa.5631.3.3
03BC114A5D150123FF451012FE2AFA6C.taxon	description	Morphological Characterization. Rostrum almost straight, reaching the distal end of the antennular peduncle, with 13 – 16 regularly spaced teeth on the upper margin, 5 – 6 of which are located behind the orbit. A small gap is observed between the 1 st and 2 nd teeth, which are larger than the others. Lower margin bears 1 – 3 teeth. Lower portion of orbit is convex and slightly pronounced. Scaphocerite is three times as long as it is wide; epistome bilobed with weakly developed carinae. Carapace smooth with no setae; hepatic spine smaller than antennal spine. First pair of pereiopods extends to one half to one third of the carpus beyond the scaphocerite. Fingers shorter than palm; carpus twice the propodus length, with merus being two thirds the carpus length, with some variation. Second pair of pereiopods (P 2) significantly unequal in shape and size, with a high incidence of spines; larger pereiopods reached from one half of the merus to one half of the carpus beyond the scaphocerite. Fixed finger has two to five small teeth and one large tooth in the proximal portion of the cutting edge, followed by five to six smaller teeth from the finger to its distal portion. The smaller P 2 has fingers forming a gap, cutting edge has two to five small teeth and one large tooth in the proximal part, and longitudinal rows of spinules on the palm and fingers, with the inner ones being larger and more widely spaced. Carpus has the same length as palm and slightly longer than merus. Along the upper margin of the chela, there is a row of teeth with the highest incidence on palm, decreasing in size toward the fingers. Pleon smooth; pleura of the 5 th somite slightly acute. Internal appendage of second pair of pleopods longer than the male appendage. Preanal carina small and rounded, with or without apex setae. Posterior margin of telson has a sharp median point with two pairs of posterior cuspidate setae, where the inner cuspidate setae extend beyond the posterior margin of the telson, with many long setae between them. Sexual dimorphism. Females have a less-developed second pair of pereiopods, which are slightly unequal in shape and size, with a reduced number of teeth. Half of the carpus goes beyond the end of the scaphocerite. The distribution of teeth along the cutting edge is similar to that in males but they are less developed.	en	Cardim, Robert Wagner Dos Santos, Mota, Thaís Arrais, Carvalho, Fabrício Lopes (2025): Taxonomic assessment of the shrimp Macrobrachium denticulatum Ostrovski, da Fonseca & da Silva-Ferreira, 1996 (Decapoda: Palaemonidae) using molecular and morphological data: a comparison with M. olfersii (Wiegmann, 1836). Zootaxa 5631 (3): 475-494, DOI: 10.11646/zootaxa.5631.3.3, URL: https://doi.org/10.11646/zootaxa.5631.3.3
03BC114A5D150123FF451012FE2AFA6C.taxon	distribution	Distribution. Endemic species of the São Francisco River, between states of Alagoas and Sergipe, Brazil (Ostrovski et al. 1996).	en	Cardim, Robert Wagner Dos Santos, Mota, Thaís Arrais, Carvalho, Fabrício Lopes (2025): Taxonomic assessment of the shrimp Macrobrachium denticulatum Ostrovski, da Fonseca & da Silva-Ferreira, 1996 (Decapoda: Palaemonidae) using molecular and morphological data: a comparison with M. olfersii (Wiegmann, 1836). Zootaxa 5631 (3): 475-494, DOI: 10.11646/zootaxa.5631.3.3, URL: https://doi.org/10.11646/zootaxa.5631.3.3
03BC114A5D150123FF451012FE2AFA6C.taxon	discussion	Remarks. There are variations in the length relationship between the second pair of pereiopods and the scaphocerite, with one half of the carpus to one half of the merus extending beyond the scaphocerite, and even the distal part of the merus reaching the scaphocerite, diagnostic characters also present in M. olfersii. Another inconsistent diagnostic character when compared to M. olfersii is the number of teeth on the cutting edge of the fixed finger, which varies considerably. The fixed finger may have two to five small teeth and one larger tooth in the proximal portion.	en	Cardim, Robert Wagner Dos Santos, Mota, Thaís Arrais, Carvalho, Fabrício Lopes (2025): Taxonomic assessment of the shrimp Macrobrachium denticulatum Ostrovski, da Fonseca & da Silva-Ferreira, 1996 (Decapoda: Palaemonidae) using molecular and morphological data: a comparison with M. olfersii (Wiegmann, 1836). Zootaxa 5631 (3): 475-494, DOI: 10.11646/zootaxa.5631.3.3, URL: https://doi.org/10.11646/zootaxa.5631.3.3
03BC114A5D140124FF4512C4FE1CF82C.taxon	materials_examined	Material Examined. Suriname. 1 female (CL 8.29 mm) and 1 male (7.15 mm) DZ / UFRGS 661: Suriname river, Kabel station, 21 – 28 Oct. 1928, collector: Geyskes, D. C; Brazil. Alagoas. 2 males (CL 18.37, 19.38 mm) CIASBM 20180192 UFSB: rio Paraíba, Atalaia, 18 Feb. 1995, collector: Alvarenga, S. R.; 1 male (CL 15.52 mm) CIASBM 20250012 UFSB: Piranhas, Brazil, 01 June 2022, collector: Coelho Filho, P.; 1 male (CL 14.31 mm) CIASBM 2022007 UFSB: Penedinho, 01 June 2022, collector: Coelho Filho, P.; 1 female (CL 8.05 mm) and 8 males (CL 5.36 – 9.49 mm) CIASBM 20250009 UFSB: Penedinho, 01 June 2022, collector: Coelho Filho, P.; 4 males (CL 9.40 – 11.30 mm) CIASBM 20250010 UFSB: Penedinho, 01 April 2022, collector: Coelho Filho, P.; 1 female (CL 5.19 mm) and 8 males (6.11 – 10.21 mm) CIASBM 20250011 UFSB: Penedinho, 01 April 2022, collector: Coelho Filho, P.; 1 male (CL 15.51 mm) CIASBM 20250012 UFSB: Piranhas Brazil, collector: Coelho Filho, P .. Bahia: 1 male (CL 11.95 mm) CIASBM 2018026 UFSB: rio Tijuípe, Itacaré, 08 April 2017, collector: Nascimento, J. S.; 1 male (CL 11.30 mm) CIASBM 20250007 UFSB: rio Burundanga, Itacaré, 02 June 2019, collector: Novais, W. R.; 2 females (CL 9.60 mm and 9.03 mm) and 13 males (5.71 – 12.72 mm) CIASBM 20190127 UFSB: rio Tijuipinho, Itacaré, 16 April 2019, collector: Carvalho, F. L.; 1 male (CL 14.49 mm) CIASBM 20170009 UFSB: Serqueiro de Piraúne, Ilhéus, no collection date, collector: not identified; 8 males (CL 9.17 – 12.49 mm) CIASBM 20250013 UFSB: Córrego da Presa RPPN Capitão, Itacaré, 18 March 2022, collector: Novais, W. R.; 1 male (CL 10.19 mm) CIASBM 20180259 UFSB: rio Burundanga, Itacaré, 19 May 2017, collector: Carvalho, F. L.; 1 male (CL 11.25 mm) CIASBM 20190001 UFSB: Itacaré, no collection date, collector: Carvalho, F. L.; 1 male (CL 08.21 mm) CIASBM 20250014 UFSB: rio Cachoeira Ilhéus, 18 March 2022, collector: Novais, W. R.; 1 female (CL 13.12 mm) and 4 males (CL 11.19 – 17.29 mm) CIASBM 20250015 UFSB: Distrito de Derradeira, Valença, 09 Sept. 2017, collector: Abel; 1 male (CL 14.35 mm) CIASBM 20180251 UFSB: rio Burundanga, Itacaré, 19 Dec. 2017, collector: Nascimento, J. S. Espírito Santo: 1 male (CL 16.51 mm) DZ / UFRGS 412: Itapemirim, 10 Oct. 1978, collector: Vilela, M.; 3 males (12.23 – 18.32 mm) DZ / UFRGS 3371: Rio Itapemirim, Jun. 1989, collector: Martins, M. E.; Rio de Janeiro: 3 females (11.43 – 12.20 mm) and 3 males (CL 8.39 – 16.41 mm) CIASBM 20250016 UFSB: Fazenda Bananal de Baixo, Parati, 07 April 2018, collector: Souza, G. Paraná: 1 male (CL 09.48 mm) DZ / UFRGS 1146: Morretes, 07 Sept. 1988, collector: Buckup. São Paulo: 18 males (7.19 – 15.56 mm) DZ / UFGRS 3081: Juréia, 14 Dec. 2000, collector: Rocha, S.; Rio Grande do Sul: 3 males (CL 10.82 – 12.95 mm) DZ / UFRGS 709: Tramandaí, 30 Oct. 1994, collector: Rocha, S: Fontana, N. F.; 2 males (8.15, 9.11 mm) DZ / UFRGS 716: Tramandaí, 11 Apr. 1984, collector: Fontoura, N. 1 female (10.18 mm) and 5 males (10.23 – 16.28 mm) DZ / UFRGS 810: Tramandaí, 2 Dec. 1985, collector: Bond, G.	en	Cardim, Robert Wagner Dos Santos, Mota, Thaís Arrais, Carvalho, Fabrício Lopes (2025): Taxonomic assessment of the shrimp Macrobrachium denticulatum Ostrovski, da Fonseca & da Silva-Ferreira, 1996 (Decapoda: Palaemonidae) using molecular and morphological data: a comparison with M. olfersii (Wiegmann, 1836). Zootaxa 5631 (3): 475-494, DOI: 10.11646/zootaxa.5631.3.3, URL: https://doi.org/10.11646/zootaxa.5631.3.3
03BC114A5D140124FF4512C4FE1CF82C.taxon	description	Morphological Characterization. Rostrum straight with a slight downward tilt, sometimes narrow, extending beyond or not reaching the distal end of the antennular peduncle. Upper margin has 12 – 16 regularly spaced teeth, often 14, with the proximal tooth slightly more distant from the others. Three to six teeth are located behind the orbit, most commonly five. Lower margin contains two to four teeth. Post-orbital margin is convex. Width of scaphocerite approximately one third of its length. Epistome divided into two lobes with rounded carinae. Carapace smooth, with the hepatic spine being smaller than the antennal spine. First pair of pereiopods with from one half of the carpus to half of the merus overreaching the scaphocerite. Articles are smooth with a few setae. Second pair of pereiopods unequal, with the larger one extending beyond the scaphocerite with half of the carpus to the distal part of the merus and the smaller one overreaching the scaphocerite with half of the propodus to half of the carpus. Larger cheliped of second pair of pereiopods shows variation in finger size, with a gap between fingers and rigid setae. Fixed finger has two to four small teeth in the proximal region of the cutting edge, followed by one larger distal tooth. Propodus slightly or significantly inflated. Longitudinal rows of spines and spinules welldistributed and closer together in the upper and lower parts, with a higher concentration in the median region of the propodus. Velvety pubescence present throughout the propodus, with long, rigid setae. Dorsal part of the chela has many smaller spines in the fixed finger region. Carpus varies in length and is shorter than or equal to the length of the merus. Carpus and merus robust with smaller and more widely spaced spinules ventrally. Ischium is half the length of the merus. Pleonal region smooth. Pleura of the fifth somite rectangular. Internal appendage of the second pair of pleopods is longer than male appendage. Preanal carina small and rounded, with or without apex setae. Telson has a posterior margin with a sharp median tip and two pairs of posterior cuspidate setae, where the inner ones extend beyond the posterior margin of the telson with long setae present between them. Sexual dimorphism: The presence of heterochely was less pronounced in females, with the larger cheliped being less developed than that in males. Females exhibited minimal pubescence.	en	Cardim, Robert Wagner Dos Santos, Mota, Thaís Arrais, Carvalho, Fabrício Lopes (2025): Taxonomic assessment of the shrimp Macrobrachium denticulatum Ostrovski, da Fonseca & da Silva-Ferreira, 1996 (Decapoda: Palaemonidae) using molecular and morphological data: a comparison with M. olfersii (Wiegmann, 1836). Zootaxa 5631 (3): 475-494, DOI: 10.11646/zootaxa.5631.3.3, URL: https://doi.org/10.11646/zootaxa.5631.3.3
03BC114A5D140124FF4512C4FE1CF82C.taxon	distribution	Distribution: Recorded occurrences in the southern United States, Mexico, Costa Rica, Nicaragua, Panama, Colombia, Venezuela, Guyana, Suriname, and along the entire Atlantic coast of Brazil (Ortmann 1897; Holthuis 1952; Holthuis & Provenzano 1970; Anderson & Filingame 1980; Williams 1984; Barros 1995; Melo 2003).	en	Cardim, Robert Wagner Dos Santos, Mota, Thaís Arrais, Carvalho, Fabrício Lopes (2025): Taxonomic assessment of the shrimp Macrobrachium denticulatum Ostrovski, da Fonseca & da Silva-Ferreira, 1996 (Decapoda: Palaemonidae) using molecular and morphological data: a comparison with M. olfersii (Wiegmann, 1836). Zootaxa 5631 (3): 475-494, DOI: 10.11646/zootaxa.5631.3.3, URL: https://doi.org/10.11646/zootaxa.5631.3.3
03BC114A5D140124FF4512C4FE1CF82C.taxon	discussion	Remarks. The presence of morphotypes in M. olfersii was previously identified by Santos et al. (2022). Therefore, the variability observed in the second pereiopod in the present study encompasses the morphotypes described for the species.	en	Cardim, Robert Wagner Dos Santos, Mota, Thaís Arrais, Carvalho, Fabrício Lopes (2025): Taxonomic assessment of the shrimp Macrobrachium denticulatum Ostrovski, da Fonseca & da Silva-Ferreira, 1996 (Decapoda: Palaemonidae) using molecular and morphological data: a comparison with M. olfersii (Wiegmann, 1836). Zootaxa 5631 (3): 475-494, DOI: 10.11646/zootaxa.5631.3.3, URL: https://doi.org/10.11646/zootaxa.5631.3.3
