Segonzacia mesatlantica, (WILLIAMS, 1988)

Martin, Joel W. & Haney, Todd A., 2005, Decapod crustaceans from hydrothermal vents and cold seeps: a review through 2005, Zoological Journal of the Linnean Society 145 (4), pp. 445-522 : 492-493

SEGONZACIA MESATLANTICA ( WILLIAMS, 1988)

Type locality (as Bythograea mesatlantica ): North Atlantic Ocean , MAR, 70 km south of Kane Fracture Zone, MARK vent, sta. 1; 23°22.09′N, 44°57.12′W; 3437 m .

Known range: North Atlantic, hydrothermal vent fields of the MAR, including Snake Pit (3480 m) and Lucky Strike (1700 m) ( Guinot, 1989; Guinot, 1997, in Desbruyères & Segonzac, 1997; Turnipseed et al., 2004), Logatchev ( Gebruk et al., 2000a) and, tentatively, at Menez Gwen ( Colaço et al., 1998; Sanglier et al., 2003).

Material: type locality; NSF Ocean Drilling Program Leg 106, Alvin dive 1683; 30 May 86; scoop; USNM 234300 (holotype female) ( Williams, 1988) .

– Snake Pit hydrothermal site; 23°22.094′N, 44°56.946′W; 3478 m; HYDROSNAKE cruise 1988, Nautile dive HS 03; 21 June 1988; MNHN-B 20612 (non-type, 1 male). –same locality; Nautile dive HS 08; 26 June 1988; MNHN-B 20613 (non-types: 2 females, 1 juvenile). –same locality; Nautile dive HS 10; 28 June 1988; MNHN-B 20614 (non-type, 1 female). –same locality; Nautile dive HS 10, 28 June 1988; MNHN-B 20615 (non-types, 2 females) ( Guinot, 1989) .

–Menez Gwen hydrothermal field; 850 m; ATOS’01 cruise; number and fate of specimens not given ( Sanglier et al., 2003).

Remarks: This species was reported in the literature as Bythograea sp. by Grassle et al. (1986) and observed by Rona et al. (1986). It was originally described as Bythograea mesatlantica by Williams (1988) and was later transferred to the genus Segonzacia by Guinot (1989), who also provided a thorough treatment of its morphology and ecology. The species was described by Guinot (1997, in Desbruyères & Segonzac, 1997) as being ‘necrophagous, feeding on dead shrimps and exuviae’. Segonzacia mesatlantica has been observed at many Mid-Atlantic vent sites (see above) and remains the sole vent-endemic crab from the MAR sites. Desbruyères et al. (2000: table 4) listed the species as being rare or patchy but ‘dominant carnivorous’ at Logatchev, Snake Pit, TAG, Broken Spur, Rainbow, Lucky Strike and Menez Gwen (see also Colaço et al., 2002); however, Gebruk et al. (2000a) did not mention it in their study of the Logatchev fauna. Haemocyanin protein structure was studied by Sanglier et al. (2003), and respiratory adaptations were investigated by Chausson et al. (2004). The organ of Bellonci and sinus gland were described by Charmantier-Daures & Segonzac (1998). Tudge et al. (1998) described the ultrastructural morphology of the sperm and compared it with that of other vent crab genera.

FAMILY CANCRIDAE LATREILLE, 1802