Synalpheus herricki Coutière, 1909 (Figs. 13, 14)

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, 03º51.892′S 32º27.965′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 .

Description: Coutière (1909), Dardeau (1984), Ríos & Duffy (2007), Anker et al. (2012).

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).

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).

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. 30C) 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. 13B) (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. 13F; Dardeau 1984, fig. 28C), and the absence of a sinus between the anterior and posterior portions of the third to fifth pleurae (vs. sinus present) (Fig. 14A; Dardeau 1984, fig. 30C). These variations highlight the need for integrative approaches to more accurately characterize the range of morphological differences within the species.