Garthambrus posidon Ng, 1996

Mclay, Colin L., 2009, Revision of the crab genus Garthambrus Ng, 1996, with the description of two new genera and discussion of the status of Tutankhamen Rathbun, 1925 (Crustacea: Brachyura: Parthenopidae), Zootaxa 2122, pp. 1-50 : 17

Garthambrus posidon Ng, 1996

( Figs 6 E, F, 13A)

Garthambrus posidon Ng, 1996: 159 , figs 1–5. – Ng & Tan 1999: 122.

Type material. HOLOTYPE: male 66.1 x 41.6 mm, ( RMNH D 42686), data after Ng (1996) (not examined), Seychelles, south of Alphonse Atoll, Tyro Seychelles Expedition 1992/93, stn 794, 7º03’S, 52º43’E, on coral rubble with poor epifauna, 480–600 m, rectangular dredge, 5–6 Jan 1993.

Material examined. Madagascar. Stn P3, trawl 37, 12º51’S, 48º06.30’E, 675–705 m, A. Crosnier coll., 14 Sep 1972: 1 male 35.3 x 23.8 mm (MNHN-B31871). – Stn unknown, trawl 119, 12º50.7’S, 48º06.0’E, 750–765 m, A. Crosnier coll., 10 Oct 1974: 1 male 39.4 x 26.5 mm (MNHN-B31872).

Diagnosis. Carapace surface sparsely tuberculate, not spinose, without deep lacunae; supra-orbital region not spinose. Tubercles on protogastric, mesogastric, epibranchial, mesobranchial and cardiac regions not fusing together to form smooth ridges or plates. Frontal projection short, less than one quarter carapace length. Tips of epibranchial margin teeth acute. Mesobranchial margin without a raised smooth triangular patch. Suborbital spine produced, spine tip extending beyond anterior outer corner of antennal article 2. Sub-branchial region tuberculate. Cheliped merus and carpus outer margin dentate, teeth low, tips blunt. Upper margin of P5 merus, carpus and propodus tuberculate; posterior surface of merus, carpus and propodus smooth.

Distribution. Seychelles and here for the first time Madagascar.

Remarks. Garthambrus posidon bears some resemblance to G. poupini in the morphology of the carapace. Ng (1996) listed several other characters that can be used to differentiate these species. The CW/CL ratio in G. posidon is larger (1.5–1.6) compared with 1.3 in G. poupin i. Another character is the shape of the epibranchial teeth, which are short but sharp in G. posidon , but blunt, the larger ones becoming slightly paxilliform, in G. poupini .

Figures

FIGURE 6. Gonopods. Garthambrus darthvaderi sp. nov.: A, B, holotype, male 19.9 x 14.0 mm (MNHN), New Caledonia, BIOCAL, stn DW 44, 22 ° 47 ’ S, 167 ° 14 ’ E, 440 – 450 m, 30 Aug 1985. — Garthambrus lacunosus (Rathbun, 1906): C, D, holotype, male 30.9 x 21.8 mm (USNM 29842), Hawaiian Is, west coast of Hawaii, Kawaihae. — Garthambrus posidon Ng, 1996: E, F, male 35.3 x 23.8 mm (MNHN), Madagascar; A, C, left G 1; B, D, left G 2; E, right G 1; F, right G 2. Scale bar = 1 mm.