Synalpheus sanctithomae Coutière, 1909

Anker, Arthur, Tavares, Marcos & Mendonça, Joel B., 2016, Alpheid shrimps (Decapoda: Caridea) of the Trindade & Martin Vaz Archipelago, off Brazil, with new records, description of a new species of Synalpheus and remarks on zoogeographical patterns in the oceanic islands of the tropical southern Atlantic, Zootaxa 4138 (1), pp. 1-58 : 38

Synalpheus sanctithomae Coutière, 1909

Synalpheus sanctithomae Coutière 1909: 61 , fig. 35; Christoffersen, 1979: 352, figs. 29, 30; Gore 1981: 152; Dardeau 1984: 104; Christoffersen 1998: 363; Abele & Kim 1986: 202, 220, 221, figs. d, e; Rodríguez 1986: 208, fig. 49; Coelho Filho 2006: 9; Alves et al. 2008: 50; Souza et al. 2011: 48.

Zuzalpheus sanctithomae— Ríos & Duffy 2007: 62 , pl. 5.

Synalpheus laevimanus longicarpus— Rathbun 1901: 110 (partim) (not S. longicarpus Herrick, 1891 ).

Material examined. Brazil: 1 ovig. female, MZUSP 34144, Trindade Island, Enseada dos Portugueses, off SECON, 20°30’20.9.3”S– 29°18’43.7”W, depth: 10.2 m, coll. J.B. Mendonça, 22.xi.2014; 1 male, 1 ovig. female, MZUSP 34139, Trindade Island, Enseada do Príncipe, Ilha Sul, 20°31’34.3”S – 29°19’27.9”W, depth: 17.6 m, coll. J.B. Mendonça, 06.xi.2014; 1 male, 1 ovig. female, MZUSP 34136, Trindade Island, Enseada do Príncipe, Ilha Sul, 20°31’34.3”S – 29°19’27.9”W, depth: 22.2 m, in sponge growing within calcareous algae, coll. J.B. Mendonça, 10.vii.2015; 2 males, 2 ovig. females, MZUSP 34137, same collection data; 2 males, 1 ovig. female, OUMNH.ZC. 2016.02.0 17, same collection data. Size of largest male: cl 3.8 mm ( MZUSP 34139); largest female: cl 3.5 mm ( MZUSP 34144).

Additional (extra-limital) material examined. Brazil: 1 male, 1 ovig. female, MZUSP 32025, REVIZEE— Comissão Central sta. 7BT(025), Rio de Janeiro, off Macaé, Almirante Saldanha Seamount, 22º23’S – 37º35’W, depth: 105 m, 08.ii.1996.

Description. See Coutière (1909) for original description and illustrations, Christoffersen (1979) for additional figures, and Ríos & Duffy (2007) for a colour photograph.

Distribution. Western Atlantic: Florida; throughout Caribbean Sea; Brazil: Pernambuco to Bahia, Atol das Rocas , Almirante Saldanha Seamount, Trindade Island ( Christoffersen 1979; Gore 1981; Rodríguez 1986; Ríos & Duffy 2007; present study).

Ecology. Coral reefs and other hard bottom habitats rich in porous rocks, clumps of calcareous algae, sponges; obligate associate of a variety of sponges (e.g., in the western Caribbean Sea: Hymeniacidon, Agelas , Hyattella , Lissodendoryx ) ( Ríos & Duffy 2007); typical depth range: 1–20 m, exceptionally to 105 m (present study).

Remarks. Synalpheus sanctithomae is a relatively distinctive species of the S. gambarelloides group, most easily recognisable by a short rostral carina and the presence of a distinct bump on the mesial side of the major chela pollex. The present material extends the previously known southern distribution limit of S. sanctithomae from Bahia southeastwards to Trindade Island off Espírito Santo and further south to Almirante Saldanha Seamount off Rio de Janeiro.