Garthambrus lacunosus (Rathbun, 1906)

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 : 16-17

Garthambrus lacunosus (Rathbun, 1906)

( Figs 6 C, D, 12A, B)

Parthenope (Platylambrus) stellata lacunosa Rathbun, 1906: 884 , pl. 15 fig. 7. Parthenope (Platylambrus) lacunosa — Garth 1993: 788.

Parthenope lacunosa — Garth & Davie 1995: 226, fig. 3A.

Garthambrus lacunosa — Ng 1996: 156, 158. – Ng & Tan 1999: 122, 126, figs 2A–B, 3A–C, 6D–F.

Type material. HOLOTYPE: male, 30.9 x 21.8 mm ( USNM 29842), Hawaiian Is, west coast of Hawaii, Kawaihae, RV Albatross, stn 4045, 20º01’45”N, 155º54’15”W, 147–198 fm (269–362 m), 8 hemp tangles gear, 11 Jul 1902.

PARATYPES: 1 female 30.2 x 21.3 mm ( USNM 29841), Hawaiian Is, south coast of Molokai, off Lae-O- Ka Laau Lighthouse, RV Albatross, stn 3835, 64º00’N, 00º13’42”W, 169–182 fm (309–333 m), 3 Apr 1902; 1 male 30.0 x 20.7 mm ( USNM 29843a), Hawaiian Is, Pailolo Channel, between Maui and Molokai islands, southeast of Mokuhooniki Islet, RV Albatross, stn 4100, 21º05’30”N, 156º40’30”W, 8 hemp tangles gear, 130–151 fm (238–276 m), 23 Jul 1902; 1 female ( USNM 29844) (not examined); 1 male, transferred to Stanford University (not examined; see Ng & Tan 1999), Hawaiian Is, Northwest coast of Oahu, RV Albatross, stn 4114, 154–195 fm (282–357 m).

Material examined. Indonesia. KARUBAR, Kai Is, stn DW32, 5º47’S, 132º51’E, 170–206 m, 26 Oct 1991: 1 female 19.2 x 14.4 mm (MNHN-B31870).

Hawaiian Islands. Pailolo Channel, between Maui and Molokai islands, southeast of Mokuhooniki Islet, RV Albatross, stn 4100, 130–151 fms (238–276 m), 23 Jul 1902: 1 male 30.9 x 21.0 mm ( USNM 29843b).

Diagnosis. Carapace tuberculate, not spinose, with deep lacunae on protogastric, epibranchial and cardiac regions; supra-orbital region not spinose. Tubercles on protogastric, mesogastric, epibranchial and cardiac regions fuse together to form smooth ridges or plates. Frontal projection short, less than one quarter carapace length. Epibranchial marginal teeth triangular, tips sharp. Mesobranchial margin without raised smooth triangular patch. Sub-orbital spine not produced, spine tip not extending beyond anterior outer corner of antennal article 2. Posterior sub-branchial region tuberculate. Cheliped merus and outer margins dentate, teeth triangular; carpus outer margin entire. Upper margins of P5 merus, carpus, propodus cristate; posterior surface of merus, carpus, propodus smooth.

Distribution. Kai Is, Indonesia and Hawaiian Is.

Remarks. Rathbun (1906) originally described this species as a subspecies of G. stellatus . Ng & Tan (1999) showed that it is distinct from G. stellatus (Rathbun, 1906) . This species is actually very similar to G. pteromerus (Ortmann, 1893) primarily due to the less strongly tuberculate carapace dorsal surface and the presence of lamelliform cristae on the ambulatory legs. However, G. lacunosus can be easily differentiated from G. pteromerus by the strongly tuberculate sub-branchial region, which is smooth in G. pteromerus .

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.