Caenopedia, Ng, Peter K. L. & Castro, Peter, 2013

Ng, Peter K. L. & Castro, Peter, 2013, On the genus Scalopidia Stimpson, 1858 (Crustacea: Brachyura: Goneplacoidea: Scalopidiidae), with the description of one new genus and three new species, Zootaxa 3731 (1) : -

Caenopedia n. gen.

Type species. Caenopedia ocularia n. sp., by present designation.

Diagnosis. Carapace with convex dorsal surface, regions demarcated; cardiac region slightly raised; front distinctly bilobed, with median cleft; anterolateral margin strongly arcuate, granular, without distinct lobes or teeth, not clearly separated from posterolateral margin. Eye peduncle relatively stout, completely filling orbit. mobile; cornea distinct, completely pigmented. Third maxillipeds relatively short, almost completely covers buccal cavern when closed; ischium rectangular with prominent submedian oblique sulcus; merus quadrate, anteroexternal angle strongly auriculiform; exopod relatively broad, with long flagellum. Chelipeds prominently unequal, heteromorphic in adult males; basis-ischium surface with several short spines; ventral margins of merus lined with short spines; carpus with long sharp tooth on inner dorsal angle; outer surface of chelae smooth or punctate; major chela: fingers subequal in length to palm, pollex not bent, ventral margin forming gentle concavity with rest of palm, dactylus long, cutting margins with distinct teeth, denticles, sub-basal tooth on dactylus distinct but not enlarged; minor chela: fingers slender, elongated, longer than palm, pollex gently curved, ventral margin forming gentle concavity with rest of palm, dactylus relatively long, cutting margins with low teeth, denticles. Ambulatory legs long; anterodorsal margin of ambulatory coxa with row of 2–4 short spines, ventral surface with 1 or 2 short spines; basis-ischium with 2 or 3 short spines; dorsal, ventral margins of meri with sharp granules and/or low spines; dactylus of P5 recurved. Male abdomen relatively broad, somites 4–6 much wider than long; somite 3 much wide than somite 1.

Etymology. The name is derived from an arbitrary combination of the Latin caeno and pedia for “mud” and “legs”, respectively, alluding to the muddy habitat of the type species. The gender is feminine.

Remarks. The recognition of a separate genus for the present new species is necessary because the three species of Scalopidia from the West Pacific and eastern Indian Ocean all have the eye peduncle fused to the orbit. In contrast, the eye peduncle of Caenopedia n. gen. is fully mobile. The male abdomen of Caenopedia n. gen. is also proportionately broader, especially somites 6 and telson ( Figs. 9 G, H versus Figs. 9 A–F), with male abdominal somite 3 distinctly wider than somite 1 ( Fig. 9 G) (versus widths of somites 1 and 3 subequal, Figs. 9 A, C, E).

Caenopedia ocularia n. sp.

( Figs. 4 , 5 D, 6D, 8E, F, 9G, H, 13E–G, 14C)

Material examined. Holotype —male (11.2×15.0 mm) (MNHN-IU-2010-1573), station DW 3202, west of Cap d’Ambre, between Nosy-B and Banc du Leven, 1235.2’S 4849.94’E, Madagascar, 42–44 m, MIRIKI, 29 June 2009. Paratypes — Madagascar: 1 female (10.3×14.0 mm) (MNHN-IU-2010-1032), same data as holotype.— 1 female (13.5× 18.3 mm) (ZRC 2013.1415, ex MNHN-IU-2010-1028), station CP 3203, south of Cape Saint-Sbastian, 1235.92’S 4835.22’E, 50–52 m, MIRIKI, 29 June 2009.

Diagnosis. Carapace quadrate, lateral margins gently convex with posterolateral sides subparallel ( Fig. 4 A, C); dorsal carapace surface almost even with regions of similar convexities ( Figs. 4 A, C, 5D); cornea entirely pigmented ( Fig. 5 D); cheliped carpus with long sharp tooth on inner dorsal angle, distal margin distinctly granular; P2–4 carpus almost completely unarmed except for weakly rugose lateral, marginal ridges ( Fig. 4 A, C); P2–4 merus dorsal margins lined with small granules, those on subdistal part more spinular ( Fig. 4 A, C); P2–4 merus ventral margins lined with 4–6 sharp vertical spines or sharp granules on proximal half, armature strongest on P4 ( Fig. 4 A, C); P5 merus dorsal margin with scattered small, sharp granules; P5 merus ventral margin with 1-7 spinules or sharp granules on proximal third ( Figs. 4 A, C, 8E, F); surface of thoracic sternum granular ( Fig. 9 G, H); male abdomen relatively broader, somites 4–6 wider than long, somite 3 much wider than somite 1 ( Fig. 9 G, H); G1 sinuous with lateral surfaces lined with short spinules ( Fig. 13 E, F).

Etymology. The name of the species is derived from the Latin oculus for “eye”, to refer to its characteristically mobile eyes.

Remarks. The tip of the left G1 of the only male specimen is broken, and as such, the right one has been figured ( Fig. 13 E, F). See Fig 4 C for colour in life.

Figures

FIGURE 4. Caenopedia ocularia n. sp.: A, B, holotype male (11.2 × 15.0 mm) (MNHN-IU- 2010 - 1573), Madagascar; C, D, paratype female (13.5 × 18.3 mm) (ZRC 2013.1415), Madagascar. A, C, overall dorsal views; B, D, outer views of chelae.

FIGURE 5. Frontal views. A, Scalopidia spinosipes, male (14.8 × 20.4 mm) (ZRC 2000.1343), South China Sea; B, Scalopidia indica n. sp., holotype male (15.3 × 21.7 mm) (ZRC 1999.0136 a), Andaman Sea; C, Scalopidia spectabilis n. sp., holotype male (11.5 × 16.6 mm) (MNHN-IU- 2013 - 505), Papua New Guinea; D, Caenopedia ocularia n. sp., holotype male (11.2 × 15.0 mm) (MNHN-IU- 2010 - 1573), Madagascar.

FIGURE 9. Male thoracic sternum and abdomen. A, B, Scalopidia spinosipes, male (14.8 × 20.4 mm) (ZRC 2000.1343), South China Sea; C, D, Scalopidia indica n. sp., holotype male (15.3 × 21.7 mm) (ZRC 1999.0136 a), Andaman Sea; E, F, Scalopidia spectabilis n. sp., holotype male (11.5 × 16.6 mm) (MNHN-IU- 2013 - 505), Papua New Guinea; G, H, Caenopedia ocularia n. sp.: holotype male (11.2 × 15.0 mm) (MNHN-IU- 2010 - 1573), Madagascar.

FIGURE 13. Gonopods. A – D, Scalopidia spectabilis n. sp., holotype male (11.5 × 16.6 mm) (MNHN-IU- 2013 - 505), Papua New Guinea; E – G, Caenopedia ocularia n. sp., holotype male (11.2 × 15.0 mm) (MNHN-IU- 200 - 1573), Madagascar. A – C, left G 1; E, F, right G 1; D, left G 2; G, right G 2. Scales: A, D, E – G, 1.0 mm; B, C = 0.5 mm.