Ceratoplax Stimpson, 1858

Ng, Peter K. L. & Clark, Paul F., 2015, Ceratoplax margarita n. sp., a new rhizopine crab (Crustacea: Brachyura: Pilumnidae) from Papua New Guinea, with rediagnoses of C. truncatifrons Rathbun, 1914, and C. fulgida Rathbun, 1914, Zoosystema 37 (2), pp. 323-331 : 324-325

publication ID	https://doi.org/ 10.5252/z2015n2a2
publication LSID	urn:lsid:zoobank.org:pub:DF6FC413-9BD1-459B-BC25-FB8F6A0FD339
DOI	https://doi.org/10.5281/zenodo.5156016
persistent identifier	https://treatment.plazi.org/id/03AB7533-B911-FFD0-FC48-FEEFFE9C10D1
treatment provided by	Felipe
scientific name	Ceratoplax Stimpson, 1858
status

Treatment

Genus Ceratoplax Stimpson, 1858 View in CoL

Ceratoplax truncatifrons Rathbun, 1914 View in CoL ( Figs 1 View FIG ; 2 View FIG ; 4 View FIG A-C)

Ceratoplax truncatifrons Rathbun, 1914: 147 View in CoL . — Tesch 1918: 205, pl. 12, fig. 1. — Serène 1968: 91 (list). — Ng 1987: 78, 88 (discussion). — Ng et al. 2008: 143 (list).

TYPE MATERIAL. — Holotype: Philippines, ♂, 7.0 × 4.2 mm, ( USNM 46399 About USNM ), stn 5206, off western Samar, Badian Island, north 27° east, 5.75 miles, 11°31’40”N, 124°42’40”E, 32 fms, coll. R. V. Albatross , 14.IV.1908. GoogleMaps

NON- TYPE MATERIAL. — 1 ♂, 5.2 × 3.3 mm, ( NNM Cru D-2164), stn 193, on reef, Sanana Bay , east coast of Sula Besi, east of Sulawesi, coll. M. Webber, Siboga Expedition , 13-14.IX.1899 ; 1 ♂, 4.0 × 2.5 mm, 1 ♀ ovig., 3.9 × 2.4 mm, 3 ♀, 5.6 × 3.5 mm, 4.3 × 2.7 mm, 4.7 × 3.0 mm, 1 damaged ♀, ( NNM-ZMA Crust De 203018), stn 193, on reef, Sanana Bay, east coast of Sula Besi, east of Sulawesi, coll. M. Webber, Siboga Expedition , 13 Sanana Bay , east coast of Sula Besi, east of Sulawesi 14.IX.1899 .

DIAGNOSIS. — Carapace transversely subovate, width 1.52- 1.67 × length; dorsal surfaces smooth, glabrous, regions poorly demarcated, H-shaped gastric grooves barely discernible; anterolateral margin strongly convex, entire, reaching along ⅔ of lateral margin, submarginal parts smooth, not clearly demarcated from posterolateral margin; posterolateral margins almost straight, gradually converging to gently convex posterior carapace margin ( Figs 1A View FIG ; 2 View FIG A-C). Frontal margin weakly divided into two low subtruncate lobes from dorsal view, gently confluent with supraorbital margin; with low external orbital tooth ( Figs 1A, B View FIG ; 2 View FIG A-C). Orbit ovate, small, eyes with small cornea, fused to carapace, immovable ( Fig. 1B View FIG ). Posterior margin of epistome gently convex, not clearly divided into lobes ( Fig. 1B View FIG ). Anteroexternal angle of merus of third maxilliped strongly, acutely auriculiform; exopod stout ( Fig. 4C View FIG ). Male thoracic sternum wide, sternites 1 and 2 completely fused to form wide triangular structure; separated from fused sternites 3 and 4 by distinct sinuous or gently concave (towards buccal cavity) suture ( Figs 1C View FIG ; 2D, E View FIG ). Male abdomen T-shaped; somite 6 rectangular, distinctly wider than long; telson triangular, longer than somite 6 ( Figs 1C View FIG ; 2D, E View FIG ). Chelipeds stout, carpus with subdentiform inner angle and tuft of setae, outer angle sharp but not spiniform or dentiform; chela stout, fingers shorter than palm ( Figs 1A, D, E View FIG ; 2 View FIG A-C). Ambulatory legs, long; articles slender, unarmed; dactylus of last leg upcurved ( Fig. 2A, C View FIG ). G1 distinctly sinuous, subdistal part hump-like with slender tapering tip that is prominently bent, opening large ( Fig. 4A, B View FIG ).

TYPE LOCALITY. — Western Samar, Badian Island, Philippines.

DISTRIBUTION. — Known only from the type locality and Sulawesi.

REMARKS

The series of specimens from Sulawesi are smaller than the holotype male but agree in all the key carapace, third maxilliped, thoracic sternal and ambulatory leg characters of C. truncatifrons . The G1 of the smaller male (4.0 × 2.5 mm, NNM-ZMA Crust De 203018) is similar in shape to the holotype except it is slightly more bent, but is otherwise identical.

The carapace proportions of this species increase with size, and smaller specimens have reduced carapace width to length ratios. The general shape of the carapace, however, remains almost the same ( Fig. 2 View FIG A-C). See discussion for Ceratoplax margarita n. sp.