Gordonopsis phorcys, Ng & Forges, 2020

Ng, Peter K. L. & Forges, Bertrand Richer de, 2020, A revision of the deep-sea porter crabs of the genus Gordonopsis Guinot & Richer de Forges, 1995 (Crustacea, Decapoda, Brachyura, Homolidae), with descriptions of five new species, Raffles Bulletin of Zoology 68, pp. 267-307 : 292

Gordonopsis phorcys , new species

( Figs. 21–23 )

Material examined. Holotype: female (10.9 × 16.8 mm) (MNHN-IU-2008-12211 = MNHN B30261), station CP2197, southwest of Santa Isabel, 8°24.4′N, 159°22.5′E, Solomon Islands, 897–1,057 m, coll. Expedition SALOMON 2, N.O. Alis, November 2004.

Diagnosis. Female: carapace longitudinally ovate, width to length ratio 0.65, distinctly wider posteriorly than anteriorly; dorsal carapace surface with well-defined regions, separated by broad, deep grooves; lateral margin gently convex; dorsal parts with scattered soft setae that do not obscure surface; lateral parts with setae that do not obscure surface ( Figs. 21 A–C, 22A, B). Rostrum long, sharp, with 2 long, obliquely directed pseudorostral spines, just shorter than rostrum ( Fig. 21B ). Supraorbital margin relatively narrow, C-shaped; pseudorostral spines directed obliquely laterally at angle of about 45° ( Fig. 21B ). Eyes with short ocular peduncle, cornea prominent; no discernible orbit ( Fig. 21B ). Hepatic region gently inflated, with short obliquely directed spine ( Fig. 21B ). Gastric region without spines ( Fig. 21B ). Gastric groove well marked, with distinct ovate gastric fossae just above ( Fig. 21B ). Cardiac region swollen; branchial region inflated, with distinct branchio-cardiac grooves ( Fig. 21B ). Latero-posterior tubercle on carapace low, just discernible as granule ( Fig. 21B ). Base of antenna with distinct spine ( Fig. 22D ). Antennal flagellum short, second and third articles thick, setose. Epistome triangular ( Fig. 22D ). Third maxilliped pediform, merus elongate with angular external angle ( Fig. 22C ). Chelipeds long; fingers long, greater than half length of palm; surface gently rugose with scattered small granules; carpus longitudinally ovate, outer margin with 1 or 2 long spines and sometimes a third spinule, distal edge with 1 long spine, inner margin with 1 long spine, sometimes with 1 more spinule, dorsal surface with longitudinal row of 3 short spines; merus triangular in cross-section, relatively long, curved, dorsal margin with 8 spines and distal 2 spines bracketing chela, outer ventral margin with 7 or 8 spines, inner ventral margin with 5 or 6 spinules ( Fig. 22 E–H). Ambulatory legs very long; basisischium with 4 distinct curved spines on each margin, that on P4 sometimes with additional ventral spine; P2 merus with 4 spines on dorsal margin (excluding 1 distal spine), ventral margin with 1 or 2 spinules or sharp granules; P3 merus with 3 spines on dorsal margin (excluding 1 distal spine), ventral margin with 1 spinule; P4 merus with 2 spines on dorsal margin (excluding 1 distal spine), ventral margin unarmed, outer surface with 1 strong proximal spine ( Figs. 21A , 23 C–E). P5 merus slender, unarmed on all margins, reaching beyond gastric groove when folded anteriorly; carpus long, propodus short, enlarged, forming prominent pseudochela with stout, gently curved dactylus; occlusal margin of fixed finger with 8 spines, that of dactylus with 8 spines ( Fig. 23A, F, G ). Outer margin of P2 coxa with l short, stout spine on distal edge; outer margin of P3 coxa with 1 or 2 strong curved spines on each edge, outer margin of P4 coxa with 2 strong curved spines on each edge ( Figs. 22I, J , 23B, H ). Proximal part of telson subtruncate, with distal half triangular ( Fig. 23B ).

Colour. Not known.

Etymology. The species is named after Phorcys, a primordial Greek sea god, son of Gaia, brother and husband of Ceto. The name is used as a noun.

Remarks. See general discussion for comparisons with congeners.

Figures

Fig. 21. Gordonopsis phorcys, new species, holotype female (10.9 × 16.8 mm) (MNHN-IU-2008-12211), Solomon Islands. A, overall habitus; B, dorsal view of carapace; C, dorso-frontal view of carapace.

Fig. 22. Gordonopsis phorcys, new species, holotype female (10.9 × 16.8 mm) (MNHN-IU-2008-12211), Solomon Islands. A, lateral view of cephalothorax; B, frontal view of cephalothorax; C, left third maxilliped; D, ventral view showing buccal cavity, epistome, antennae, and antennules; E, outer view of merus and carpus of right cheliped; F, outer view of right carpus and chela; G, dorsal view of left cheliped; H, dorsal view of right cheliped; I, right P2–P4 coxae and basis-ischia (denuded); J, left P2–P4 coxae and basis-ischia (denuded).

Fig. 23. Gordonopsis phorcys, new species, holotype female (10.9 × 16.8 mm) (MNHN-IU-2008-12211), Solomon Islands. A, dorsal view of carapace showing relative P5 length; B, ventral view of cephalothorax showing coxae, basis-ischia, and pleon; C–F, right P2–P5, respectively (all to same scale); G, right P5 pseudochela; H, ventral view of cephalothorax showing sternopleonal cavity, coxae, and basis-ischia.