Synalpheus

Almeida, Alexandre O., Boehs, Guisla, Araújo-Silva, Catarina L. & Bezerra, Luis Ernesto A., 2012, Shallow-water caridean shrimps from southern Bahia, Brazil, including the first record of Synalpheus ul (Ríos & Duffy, 2007) (Alpheidae) in the southwestern Atlantic Ocean, Zootaxa 3347, pp. 1-35 : 19

Synalpheus ul ( Ríos & Duffy, 2007)

( Figs. 6–8 )

Zuzalpheus ul Ríos & Duffy, 2007: 63 , pl. 5, figs. 27–30.

Material examined. 1 m, 30.X.2004, Camamu Bay, trawl, St. 4 (13°54’06”S; 39°00’22”W), MZUESC 709.

Distribution. Western Atlantic—Belize, Panama, Jamaica, Curaçao, Barbados and Brazil (state of Bahia , Camamu Bay) ( Hultgren et al. 2010, 2011; present study).

Ecological notes. The single specimen came up with a trawl, and its presumed sponge remains unknown. In the Caribbean Sea, S. ul is found in the canals of various demosponge from the genera Hymeniacidon Bowerbank, 1859 , Hyatella Férussac, 1821 , Lissodendoryx Topsent, 1892 , Spirastrella Schmidt, 1868 , Agelas Duchassaing & Michelotti, 1864 and Xestospongia de Laubenfels, 1932 ( Ríos & Duffy 2007; Macdonald et al. 2009; Hultgren et al. 2010, 2011).

Previous records. Camamu Bay [ Almeida et al. 2007b, as Synalpheus cf. pandionis , in part (lot MZUESC 709, erroneously referred to as ovigerous female, p. 16, figs. 3B, C, G, and p. 17, fig. 4)].

Remarks. Almeida et al. (2007b) reported S. cf. pandionis from Camamu Bay, Bahia , based on two specimens, thus extending the southern range of the S. pandionis complex. However, a reanalysis of this material following the publication of Ríos & Duffy (2007) revealed that neither of the two specimens of S. cf. pandionis represents S. pandionis s. str. One of them has all the diagnostic characters of S. ul, originally described from Belize and Panama ( Ríos & Duffy 2007). The scaphocerite of the Bahian specimen of S. ul has a distinct blade ( Fig. 7 G) similar to that of S. pandionis . However, it differs from S. pandionis in having unequal spiniform setae on the posterior margin of the telson, with the lateral pair being shorter than the mesial pair ( Fig. 6 D); these setae are subequal in length in S. pandionis . In S. ul, the distolateral tooth of the uropodal exopod is adjacent to the preceding spiniform seta ( Figs. 6 E, F) (vs. more separated and with a small lobe between them in S. pandionis ); and the mesial protuberance (erroneously referred as lateral side in Ríos & Duffy 2007) on the base of the major chela pollex, characteristic of S. pandionis , is absent ( Fig. 7 F). Synalpheus ul also resembles S. hoetjesi Hultgren, Macdonald & Duffy, 2010 , but differs from it by the presence of a scaphocerite blade (20–75% the length of scaphocerite vs. absent or vestigial in S. hoetjesi ) ( Fig. 7 G), the shape of the distal superior margin on the major chela (gently sloping in S. ul vs. bulging over the accessory tooth in S. hoetjesi ) ( Figs. 7 A, B), and the thickness of the spiniform setae on the posterior margin of the telson (mesial subequal to lateral in S. ul vs. mesial larger than lateral in S. hoetjesi ). The present record of S. ul from Bahia , the first for Brazil and the southwestern Atlantic Ocean, significantly extends the southern range of this species.

Figures

FIGURE 6. Synalpheus ul (Ríos & Duffy, 2007), male (CL = 4.7 mm) (MZUESC 709), Camamu Bay, state of Bahia, Brazil. (A) head and cephalic appendages, dorsal view; (B) head and cephalic appendages, lateral view; (C) abdomen, lateral view; (D) telson, dorsal view; (E) left exopodite of the uropod, dorsal view; (F) right exopodite of the uropod, dorsal view; (G) left major chela, lateral view. Scale bars: A – C = 1 mm; D, E = 0.5 mm; F = 2 mm.

FIGURE 7. Synalpheus ul (Ríos & Duffy, 2007), male (CL = 4.7 mm) (MZUESC 709), Camamu Bay, state of Bahia, Brazil. (A) left major chela, distal portion, lateral view; (B) left major chela, distal portion, mesial view; (C) right minor chela, lateral view; (D) right minor chela, distal portion, mesial view; (E) right minor chela, dorsal view; (F) pollex of left major chela, ventral view; (G) right basicerite, dorsal view. Scale bars: A – C, E = 1 mm; D, F, G = 0.5 mm.

FIGURE 8. Synalpheus ul (Ríos & Duffy, 2007), male (CL = 4.7 mm) (MZUESC 709), Camamu Bay, state of Bahia, Brazil. (A) right pereiopod 2, lateral view; (B) right pereiopod 3, lateral view; (C) right pereiopod 3, distal portion, lateral view; (D) right pereiopod 4, lateral view; (E) right pereiopod 4, distal portion, lateral view; (F) right pereiopod 5, lateral view; (G) right pereiopod 5, distal portion, lateral view. Scale bars: A, B, D, F = 1 mm; C, E, G = 0.5 mm.