Carcinoplax abyssicola ( Miers, 1886 )

Castro, Peter, 2007, A reappraisal of the family Goneplacidae MacLeay, 1838 (Crustacea, Decapoda, Brachyura) and revision of the subfamily Goneplacinae, with the description of 10 new genera and 18 new species, Zoosystema 29 (4), pp. 609-774 : 628-630

Carcinoplax abyssicola ( Miers, 1886)

Pseudorhombila (Pilumnoplax) abyssicola Miers, 1885: 588 (nomen nudum).

Pilumnoplax abyssicola Miers, 1886 : xxiv, xl, xlviii, 226, 227 [in list], 228, pl. 19, figs 2, 2a, 2b [ Fiji]. — Tesch 1918:

Revision of Goneplacinae ( Crustacea, Brachyura)

155 [in list], 156 [in key], 156 [ Indonesia]. — Serène 1968: 90 [in list]. — Guinot 1969b: 526 [discussion]; 1971: 1081 [in list]. — Serène & Lohavanijaya 1973: 62 [in list], 65 [in key].

Not Pilumnoplax abyssicola – Whitelegge 1900: 158 (= Pycnoplax meridionalis ( Rathbun, 1923) n. comb.; see McNeil 1929: 150).

Carcinoplax abyssicola – Guinot 1969b: 526 [discussion]; 1989: 305, fig. 38, pl. 9, figs A-C [holotype] [ Fiji] .

TYPE MATERIAL. — Challenger, stn 173, ♂ holotype, cl 8.2 mm, cw 10.0 mm ( BMNH 84.31).

TYPE LOCALITY. — Fiji, 576 m.

MATERIAL EXAMINED. — Fiji. Challenger, stn 173, 576 m, ♂ holotype, cl 8.2 mm, cw 10.0 mm ( BMNH 84.31).

DISTRIBUTION. — Fiji ( Miers 1886) and questionably Indonesia (North Maluku, Kai Is [ Tesch 1918]). Depth: 397- 984 m.

REMARKS

Guinot (1969b: 526, as Pilumnoplax abyssicola ) commented on the position of C. abyssicola , suggesting its position in Carcinoplax sensu lato rather than in the original conception of the genus (“ Carcinoplax sensu stricto ”). The species was included in Carcinoplax in a later revision, however ( Guinot 1989).

Carcinoplax abyssicola is only known from its male holotype, a small specimen collected from Fiji (cl 8.2 mm, cw 10.0 mm; BMNH 84.31). It is close to small specimens of C. specularis Rathbun, 1914 , which has also been collected in Fiji (see Remarks of C. specularis below). The main difference between the two species is their outer orbital angles, flat and inclined posteriorly in C. abyssicola ( Miers 1886: pl. 19, fig. 2; Guinot 1989: fig. 38, pl. 9, figs A, B) but typically raised as a conspicuous process in C. specularis ( Guinot 1989: figs 24, as C. polita , 25; pl. 8, figs A, B). Guinot (1989: 307) considered C. verdensis Rathbun, 1914 , a synonym of C. specularis (see Remarks for C. specularis below), as the species closest to C. abyssicola . Carcinoplax specularis is a highly variable species, however, and its outer orbital angle ( Guinot 1989: fig. 22, as C. verdensis ) can sometimes be as flat as that of C. abyssicola . Carcinoplax abyssicola and C. verdensis were correctly differentiated by the presence of more slen- der cheliped (P1) propodi in C. abyssicola ( Guinot 1989: pl. 9, fig. C) in contrast to the conspicuously inflated ones of C. verdensis (and thus of C. specularis ) ( Guinot 1989: pl. 9, fig. F). The examination of the holotype of C. abyssicola also showed that its anterolateral teeth and ambulatory legs (P2-P5) are more slender than in C. specularis .

There are doubts that Tesch’s specimens from Indonesia ( Tesch 1918) actually belong to C. abyssicola . The specimens were collected by the Siboga Expedition but could not be found at ZMA, where all other Siboga goneplacids are deposited.