Gordonopsis mazupo Ng & Liu 2024, new species

Gordonopsis mazupo, new species (Figs. 1–5) Material examined. Holotype: male (33.4 × 24.3 mm) (SY353B6), Zhongnan Seamount, South China Sea, 13.93°N 115.41°E, 897 m, R / V Tansuo 2 cruise TS2-5, collected together with a bamboo coral by the HOV Shenhaiyongshi, dive SY353, coll. Yadong Zhou, 20 March 2021. Diagnosis. Carapace longitudinally ovate, width to length ratio 0.73, distinctly wider posteriorly than anteriorly; dorsal carapace surface inflated, prominently convex in lateral view; dorsal parts with numerous soft setae, just obscuring surface; lateral parts with denser setae, partially obscuring surface (Figs. 2A–C, 3A, C, 4A, B). Rostrum relatively short, triangular, with 2 longer, obliquely directed pseudorostral spines, distinctly longer than rostrum; proepistome triangular with gently convex lateral margins, rounded tip and a low median longitudinal ridge (Figs. 2A–C, 3A, C, D, 4A); pseudorostral spines directed anterolaterally at angle of about 30° to median axis (Figs. 2A, B, 4A). Hepatic region gently inflated, with short but distinct obliquely directed spine (Figs. 2B, C, 3A, C, D, 4A); gastric region without spines, each mesogastric region with patch of small granules (Figs. 2B, C, 4A); latero-posterior tubercle on carapace small, just visible (Figs. 1B, 2B). Third maxilliped merus elongate with angular external angle, unarmed (Fig. 3B). Chelipeds very long (Figs. 1A, 2A, 3E); basis-ischium subquadrate, outer margin with 2 spines, inner margin with 3 spines, dorsal margin with 1 large and 1 small spine (Fig. 3E); merus triangular in cross-section, long, dorsal margin with 6 spines and spinules, and 2 distal spines which bracket chela, outer ventral margin with 8 or 9 spines or spinules, inner ventral margin with 6 or 7 spines or spinules (Figs. 2A, 3E); carpus longitudinally ovate, distal edge with 1 large spine, outer margin with 4 spines and spinules, inner margin with 1 spine, dorsal surface with shallow longitudinal depression, with 2 spinules (Fig. 3F, G). Ambulatory legs very long; basis-ischium subquadrate, with 4 or 5 sharp spines, one on each corner; P2 merus with 6 spines or spinules on proximal half of dorsal margin (excluding 1 distal spine), ventral margin with 1 spinule on proximal quarter (Fig. 4C, I); P3 merus with 2 spines or spinules on proximal quarter of dorsal margin (excluding 1 distal spine), ventral margin with 1 spinule on proximal quarter (Fig. 4D, J); P4 merus with 1 spine on proximal part of dorsal margin (excluding 1 distal spine), ventral margin with 1 small sharp granule on proximal part, outer surface with 1 strong spine on proximal part (Fig. 4E, K, L); P5 merus slender, unarmed on all margins, reaching distinctly 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 or 8 spines and spinules (Fig. 4F, G, H); outer margins of P2 and P3 coxae with 1 or 2 short sharp spines; that of P4 coxa with 1 short proximal spine (Fig. 5A, B). Telson subtriangular, with proximal part distinctly wider, distal part prominently narrowing to acute tip (Fig. 4B). G1 relatively short, stout, distal part subtruncate with gently convex tip (Fig. 5C, D, E, G, H). G2 stout, tubular, subequal to G1 length, distal portion cup-shaped (Fig. 5F, I) Description of male holotype. Carapace longitudinally ovate, width to length ratio 0.73, distinctly wider posteriorly than anteriorly; dorsal carapace surface prominently convex in lateral view, inflated; regions well-defined, separated by distinct grooves; lateral margins distinctly convex; dorsal parts with numerous soft setae, just obscuring surface; lateral parts with denser setae, partially obscuring surface, relatively denser on hepatic, pterygostomial and suborbital regions (Figs. 2A–C, 3A, C, 4A, B). Rostrum relatively short, triangular, sharp, margin cristate, with 2 longer, obliquely directed pseudorostral spines (right one damaged), distinctly longer than rostrum; proepistome triangular with gently convex lateral margins and rounded tip, with a low but distinct median longitudinal ridge (Figs. 2A–C, 3C, D, 4A). Supraorbital margin relatively narrow, C-shaped; pseudorostral spines directed anterolaterally at angle of about 30° to median axis (Figs. 2A, B, 4A). Eyes with short ocular peduncle, cornea prominent; no discernible orbit (Figs. 2A–C, 3A, C, 4A). Hepatic region gently inflated, with short but distinct obliquely directed spine (Figs. 2B, C, 3A, C, D, 4A). Gastric region without spines, each mesogastric region with patch of small granules (Figs. 2B, C, 4A). Gastric groove well marked, with distinct ovate gastric fossae just above (Figs. 2A–C, 3A, C, 4A). Cardiac region swollen; branchial region inflated, with distinct branchio-cardiac grooves (Figs. 2A–C, 3A, C, 4A). Latero-posterior tubercle on carapace small, just visible (Figs. 1B, 2B). Base of antenna, with strong anteriorly directed spine adjacent to it on pterygostomial region (Figs. 3A, D). Antennal flagellum short, second and third articles thick, setose (Fig. 3D). Epistome subrectangular, posterior margin with median part subtriangular, medially divided by fissure (Fig. 3D). Third maxilliped pediform, covered with setae but unarmed; ischium rectangular, shorter than merus, with shallow longitudinal shallow groove; merus elongate, subovate, with angular external angle but unarmed, margin uneven and without spines or teeth; palp (carpus, propodus and dactylus) elongate, reaching to proximal margin of ischium (Fig. 3B). Chelipeds very long (Figs. 2A, 3E). Basis-ischium subquadrate, outer margin with 2 spines, inner margin with 3 spines, dorsal margin with 1 large and 1 small spine (Fig. 3E); merus triangular in cross-section, long, dorsal margin with 6 spines and spinules, and 2 distal spines which bracket chela, outer ventral margin with 8 or 9 spines or spinules, inner ventral margin with 6 or 7 spines or spinules (Figs. 2A, 3E); carpus longitudinally ovate, distal edge with 1 large spine, outer margin with 4 spines and spinules, inner margin with 1 spine, dorsal surface with shallow longitudinal depression, with 2 spinules (Fig. 3F, G). Chela relatively stout; outer and inner surfaces of palm gently rugose; fingers long, straight, slender, about half length of palm; cutting edge of dactylus with tooth on proximal third, rest of edge blade-like; cutting edge of fixed finger with 2 basal teeth, rest of edge unarmed (Fig. 3H, I). Coxa with strong basal spine, distal edge with rounded projection, otherwise unarmed (Fig. 4B). Ambulatory legs very long; carpus laterally compressed, long, unarmed; propodus very long, subequal or just shorter than merus, distal part of ventral margin with sharp stiff setae; dactylus almost straight except for gently curved distal part, ventral margin lined with stiff setae and spinules; basis-ischium subquadrate, with 4 sharp spines, one on each corner (right P4 has 5 spines); P2 merus with 6 spines or spinules on proximal half of dorsal margin (excluding 1 distal spine), ventral margin with 1 spinule on proximal quarter (Fig. 4C, I); P3 merus with 2 spines or spinules on proximal quarter of dorsal margin (excluding 1 distal spine), ventral margin with 1 spinule on proximal quarter (Fig. 4D, J); P4 merus with 1 spine on proximal part of dorsal margin (excluding 1 distal spine), ventral margin with 1 small sharp granule on proximal part, outer surface with 1 strong spine on proximal part (Fig. 4E, K, L); P5 merus slender, unarmed on all margins, reaching distinctly 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 or 8 spines and spinules (Fig. 4F, G, H). Outer margins of P2 and P3 coxae with 1 or 2 short sharp spines; those of P4 coxa with 1 short proximal spine (Fig. 5A, B). Sternopleonal cavity wide, surface relatively flat (Fig. 5C). Pleon subovate; all somites free, somite 4 widest; telson subtriangular, with proximal part distinctly wider, distal part prominently narrowing to acute tip (Fig. 4B). G1 relatively short, stout, distal part subtruncate with gently convex tip (Fig. 5C, D, E, G, H). G2 stout, tubular, subequal to G1 length, distal portion cup-shaped (Fig. 5F, I). Colour. Carapace yellowish; ventral surface, chelipeds and ambulatory legs orange (Fig. 1). Etymology. The species is named after the Chinese Goddess or Grandmother of the Sea, Mazu. The name is used as a noun in apposition. Remarks. Gordonopsis mazupo, new species, most closely resembles G. pacifica in the carapace shape and swollen dorsal carapace features (Fig. 3A, C), and both possess a prominent spine on proximal outer surface of P4 (Fig. 4E, K, L). The ambulatory legs (P2–P5) of G. mazupo, however, are much longer than those of G. pacifica (cf. Figs. 2A, 4C–F), with the P5 reaching well beyond the gastric groove of the carapace when folded anteriorly (Fig. 4A). In G. pacifica, the P5 reaches just slightly beyond the gastric groove (Ng & Richer de Forges, 2020: fig. 16A). In addition, the pseudorostral spines of G. mazupo are much longer than the rostrum (Fig. 2A, B) (versus pseudorostral distinctly shorter in G. pacifica; cf. Ng & Richer de Forges, 2020: fig. 14A, B); and the distal part of the G1 is slightly longer and more subtruncate in shape (Fig. 5C–E, G, H) (versus distal shorter and sharper in G. pacifica; Ng & Richer de Forges, 2020; fig. 16B, C, M, N). The long P2–P5 of G. mazupo is actually closest to the condition in G. hera; but in this species, the carapace is distinctly less inflated, with the dorsal surface flatter, the pseudorostral spines are set further apart from the rostrum; and the P5 dactylus of the pseudochela is relatively stouter (cf. Ng & Richer de Forges, 2020: figs. 17A, B, 18A, 19H).