Synalpheus sanctithomae Coutière, 1909

Material examined. Barbados: 2 non-ovigerous individuals (VIMS 08BR7103), Cement Factory, from Hyattella intestinalis . 4 non-ovigerous individuals, 1 ovigerous female (VIMS 08BR1001, 08BR1201–2), Spawnee Reef, from Agelas clathrodes . 3 non-ovigerous individuals, 1 ovigerous female (VIMS 08BR901–2, 1901), Spawnee Reef, no host recorded. Largest ovigerous female, CL 3.43, largest non-ovigerous individual, CL 2.97 mm.

Color. Ovigerous females had green ovaries and greenish-orange embryos and all individuals had a drab orange body color, deepening distally in their extremities, as in other locations (Ríos & Duffy 2007; Macdonald et al. 2009; Hultgren et al. 2010).

Hosts and ecology. In Barbaros, S. sanctithomae lived in the sponges Hyattella intestinalis and Agelas clathrodes .

Distribution. Florida, USA (Gore 1981); Virgin Islands (Coutière, 1909); Jamaica (Macdonald et al. 2009); Belize (Macdonald et al., 2006; Ríos & Duffy, 2007); Curaçao (Hultgren et al. 2010); Brazil (Christoffersen, 1979); Barbados (this study).

Remarks. In Barbados, Synalpheus sanctithomae can be distinguished from the morphologically similar species S. mcclendoni by the number of setae on the posterior margin of the telson: a sparse tuft of <6 setae in S. sanctithomae vs. a well-developed fan of 10 or more setae in S. mcclendoni (Rios & Duffy 2007) .