Gordonopsis velutina, 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 : 299

Gordonopsis velutina , new species

( Figs. 27–29 )

Material examined. Holotype: female (20.8 × 27.8 mm) (MNHN-IU-2013-2269), station CP4249, southeast of Sherburne reefs, southeast Admiralty Islands, Bismark Sea, 3°31′S, 148°05′E, 598–650 m, coll. Expedition MADEEP, N.O. Alis, 23 April 2014.

Diagnosis. Female: carapace longitudinally ovate, width to length ratio 0.75, distinctly wider posteriorly than anteriorly; dorsal carapace surface with well-defined regions, separated by broad, deep grooves; lateral margin distinctly convex; dorsal parts with numerous soft and stiff setae that almost completely obscure surface; lateral parts with denser setae that obscure surface, relatively denser on hepatic, pterygostomial and suborbital regions ( Figs. 27 A–C, 28A, B, 30C). Rostrum relatively long, sharp, with 2 long, obliquely directed pseudorostral spines, just shorter than rostrum ( Fig. 27B ). Supraorbital margin relatively narrow, C-shaped; pseudorostral spines directed obliquely laterally at angle of about 45° ( Fig. 27B ). Eyes with short ocular peduncle, cornea prominent; no discernible orbit ( Fig. 27B ). Hepatic region gently inflated, with short obliquely directed spine ( Fig. 27B ). Gastric region without spines ( Fig. 27B ). Gastric groove well marked, with distinct ovate gastric fossae just above ( Fig. 27B ). Cardiac region swollen; branchial region inflated, with distinct branchio-cardiac grooves ( Fig. 27B ). Latero-posterior tubercle on carapace barely visible only as slight swelling ( Fig. 27B ). Base of antenna with distinct spine ( Fig. 28D ). Antennal flagellum short, second and third articles thick, setose. Epistome triangular ( Fig. 28D ). Third maxilliped pediform, merus elongate with slightly rounded external angle ( Fig. 28C ). Chelipeds long; fingers long, slightly greater than half length of palm; surface gently rugose with scattered small granules; carpus longitudinally ovate, outer, distal and inner margins with 1 long spine each, dorsal surface with low ridge, unarmed; merus triangular in cross-section, relatively long, curved, dorsal margin with 6 or 7 spines and 1 distal spine adjacent to chela, outer ventral margin with 6 or 7 spines, inner ventral margin with 5 or 6 spinules ( Figs. 27A , 28 E–H). Ambulatory legs long; basisischium with small granules, not spines; P2 merus with 3 spines on dorsal margin (excluding 1 distal spine), ventral margin unarmed; P3 merus with 2 or 4 spinules on dorsal and subdorsal margins (excluding 1 distal spine), ventral margin unarmed; P4 merus with 0 or 4 spinules on dorsal and subdorsal margins (excluding 1 distal spine), ventral margin unarmed, outer surface with 1 distinct granule ( Figs. 27A , 29A , F–H). 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 7 spines, that of dactylus with 7 spines ( Fig. 29A, I, J ). Outer margins of P2–P4 coxae smooth, unarmed ( Fig. 29 C–E). Proximal part of telson subcircular with strongly convex lateral margins, distal part triangular ( Fig. 29B ).

Colour. The carapace and appendages are dirty white, with the setae yellowish-brown ( Fig. 30C ).

Etymology. The name is derived from the Latin word for velvety, alluding to the dense setae all over the body of the species.

Remarks. See general discussion for comparisons with congeners.

Figures

Fig. 27. Gordonopsis velutina, new species, holotype female (20.8 × 27.8 mm) (MNHN-IU-2013-2269), Admiralty Islands. A, overall habitus; B, dorsal view of carapace; C, dorso-frontal view of carapace.

Fig. 28. Gordonopsis velutina, new species, holotype female (20.8 × 27.8 mm) (MNHN-IU-2013-2269), Admiralty 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.

Fig. 29. Gordonopsis velutina, new species, holotype female (20.8 × 27.8 mm) (MNHN-IU-2013-2269), Admiralty Islands. A, dorsal view of carapace showing relative P5 length; B, ventral view of cephalothorax showing coxae, basis-ischia, and pleon; C, ventral view of cephalothorax showing sternopleonal cavity and coxae; D, right P2–P4 coxae and basis-ischia; E, left P2–P4 coxae and basis-ischia; F–I, right P2–P5, respectively (all to same scale); J, right P5 pseudochela.

Fig. 30. Colour in life. A, Gordonopsis hera, new species, holotype ovigerous female (21.8 × 31.2 mm) (MNHN-IU-2013-2245), Papua New Guinea; B, G. ceto, new species, holotype female (9.3 × 13.6 mm) (NTOU), South China Sea; C, G. velutina, new species, holotype female (20.8 × 27.8 mm) (MNHN-IU-2013-2269), Admiralty Islands. Photographs: A, C, Laure Corbari (MNHN); B, Chan Tin-Yam (NTOU).