Synalpheus sanctithomae Coutière Material examined. Jamaica: non-ovigerous individual, ovigerous female (VIMS 08JAM0101,02), Columbus Park, Discovery Bay, from canals of Hyattella intestinalis. Non-ovigerous individual, ovigerous female (VIMS 08JAM0704,05), Columbus Park, Discovery Bay, from canals of H. intestinalis. Nonovigerous individual (VIMS 08JAM1901), Pear Tree Bottom Reef, from canals of H. intestinalis. Nonovigerous individual (VIMS 08JAM4301), fore-reef (near M1 channel marker), Discovery Bay, from canals of unidentified white tube sponge. MaxCL ovigerous female: 3.93 mm. MaxCL non-ovigerous individual: 3.24 mm. Color. Faint to bright orange; distal portion of major chela more intensely orange; ovaries and embryos green. Hosts and ecology. In Jamaica, we found pairs of S. sanctithomae most commonly inhabiting Hyattella intestinalis, but one individual was also discovered in an unidentified, white tube sponge. In other regions, S. sanctithomae is commonly found in Hymeniacidon caerulea, H. intestinalis and Agelas cf. clathrodes. Distribution. Florida, USA (Gore 1981); Virgin Islands (Coutière 1909); Belize (Macdonald et al. 2006; Ríos and Duffy 2007); Brazil (Christoffersen 1979); Jamaica (this study). REMARKS: Synalpheus sanctithomae is easily distinguishable from its morphologically closest relative (Synalpheus mcclendoni) by the uncurved, short fingers of the major chela, and by the lack of the fan of 10 or more setae emanating from the distal margin of the telson in the latter species. It is distinguishable from S. irie n. sp. by the lack of the distal setal fan on the telson, and the different shape of both the fingers and the protuberance of the major chela.

Published as part of Iii, Kenneth S Macdonald, Hultgren, Kristin & Duffy, Emmett, 2009, The sponge-dwelling snapping shrimps (Crustacea, Decapoda, Alpheidae, Synalpheus) of Discovery Bay, Jamaica, with descriptions of four new species, pp. 1-57 in Zootaxa 2199 on pages 42-43, DOI: 10.5281/zenodo.189568