Salmoneus setosus Manning & Chace 1990

Salmoneus setosus Manning & Chace, 1990

(Fig. 11 E)

Salmoneus setosus Manning & Chace 1990: 17, fig. 9; Anker 2007: 32, fig. 6; Anker 2010: 202; De Grave et al. 2014: 6.

Material examined. Brazil: 1 non-ovig. specimen, MZUSP 30333, Trindade Island, large underwater boulder near Ponta Noroeste, 20°20’39.2”S – 29°20’32.9”W, depth: 15.3 m, coll. J.B. Mendonça, 16.vii.2012; 1 non-ovig. specimen, MZUSP 30309, Trindade Island, Enseada dos Portugueses, Praia da Calheta in front of SECON, 20°30’20.9”S – 29°18’43.7”W, depth: 12.2 m, coll. J.B. Mendonça, 18.vi.2012; 1 non-ovig. specimen, MZUSP 30959, Trindade Island, Enseada dos Portugueses, Praia da Calheta in front of SECON, 20°30’20.9”S – 29°18’43.7”W, depth: 12.2 m, coll. J.B. Mendonça, 18.vii.2012; 2 non-ovig. specimens, MZUSP 31071, same collection data; 1 non-ovig. specimen, MZUSP 30053, Trindade Island, Enseada dos Portugueses, Praia da Calheta in front of SECON, 20°30’20.9”S – 29°18’43.7”W, depth: 11.6 m, coll. J.B. Mendonça, 18.vii.2012; 1 non-ovig. specimen, MZUSP 30954, Trindade Island, Enseada da Cachoeira, Farrilhões, 20°31’22.4”S – 29°19’52.0”W, depth: 11.9 m, coll. J.B. Mendonça, 16.vi.2012; 2 non-ovig. specimens, MZUSP 30323, Trindade Island, Enseada da Cachoeira, Farrilhões, 20°31’22.4”S – 29°19’52.0”W, depth: 11.8 m, coll. J.B. Mendonça, 20.vi.2012; 1 ovig. specimen, MZUSP 33335, Trindade Island, Enseada da Cachoeira, Farrilhões, 20°31’22.4”S – 29°19’52.0”W, depth: 11.8 m, coll. J.B. Mendonça, 05.v.2014; 1 non-ovig. specimen (damaged), MZUSP 30979, Trindade Island, Enseada Orelhas, 20°29’40.2”S – 29°20’32.9”W, depth: 14.9 m, coll. J.B. Mendonça, 22.vi.2012; 1 non-ovig. specimen, MZUSP 30071, Trindade Island, Enseada Orelhas, 20°29’40.2”S – 29°20’32.9”W, depth: 13.9 m, coll. J.B. Mendonça, 30.vi.2012; 1 post-ovig. specimen, OUMNH.ZC. 2016-02-021, Trindade Island, Enseada Orelhas, 20°29’40.2”S – 29°20’32.9”W, depth: 6.9 m, coll. J.B. Mendonça, 12.xi.2014; 1 non-ovig. specimen, MZUSP 31007, Trindade Island, Ilha da Racha, 20°30’26.5”S – 29°20’40.0”W, depth: 20.8 m, coll. J.B. Mendonça, 16.vii.2013; 1 non-ovig. specimen, MZUSP 30291, Trindade Island, large underwater boulder near Ponta do Monumento, 20°30’10.3”S – 29°20’36.1”W, depth: 19.5 m, coll. J.B. Mendonça, 30.vi.2013; 2 (1 ovig.) specimens, MZUSP 33308, 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 ovig. specimen, MZUSP 33391, Trindade Island, between Ponta da Crista do Galo and Ponta Norte, 20°29’14.8”S – 29°20’13.9”W, depth: 15 m, coll. J.B. Mendonça, 21.v.2014; 1 non-ovig. specimen, MZUSP 31023, Martin Vaz Island, 20°28’26.9”S – 28°51’20.9”W, depth: 13 m, coll. J.B. Mendonça, 23.vii.2013. Size of largest non-ovigerous specimen: cl 3.3 mm (MZUSP 30954); largest of largest ovigerous specimen: cl 3.4 mm (MZUSP 33391). Several additional specimens (not listed above) are deposited in MZUSP.

Additional (extra-limital) material examined. Cayman Islands: 1 non-ovig. specimen, FLMNH UF 41697, Little Cayman Island, eastern end, Owen Island, Heard-Sta4C, coll. R. Heard, 25.v.1995.

Description. See Manning & Chace (1990) for original description and illustrations, and Anker (2007) for additional figures.

Distribution. Western-central Atlantic: Ascension Island; Caribbean Sea: Mexico, Cayman Islands; Brazil: Atol das Rocas, Fernando de Noronha, Trindade and Martin Vaz Archipelago (Manning & Chace 1990; Anker 2007, 2010; De Grave et al. 2014; present study).

Ecology. Rocky intertidal with abundance of coralline algae and coral reefs; deep in crevices of algal clumps, dead corals etc.; intertidal to about 20 m.

Remarks. The abundant material from Trindade Island represents the southern-most record of Salmoneus setosus from the Brazilian territorial waters; the species was previously known only from Atol das Rocas and Fernando de Noronha (Anker 2007). Salmoneus setosus is easy to distinguish from the other southern Atlantic species of Salmoneus by the presence of numerous thick setae on the carapace and pleon (Manning & Chace 1990; Anker 2007; setae also visible in Fig. 11 E). Although S. setosus appears to be common around Trindade Island, it can be easily overlooked due to its small size (carapace length typically less than 3.5 mm); most specimens were collected by a careful extraction of all small fauna associated with interstices of coralline algae.

The validity of Salmoneus rocas Anker, 2007, which is presently known only from the holotype from Atol das Rocas, needs to be tested by a comparison of DNA sequences as the only character distinguishing it from S. setosus is the absence of stiff setae on the carapace and pleon.