Chasmocarcinops Alcock, 1900

Ng, Peter K. L. & Castro, Peter, 2016, Revision of the family Chasmocarcinidae Serène, 1964 (Crustacea, Brachyura, Goneplacoidea), Zootaxa 4209 (1), pp. 1-182 : 45-46

Genus Chasmocarcinops Alcock, 1900

Chasmocarcinops Alcock, 1900: 334 .— Tesch 1918: 280.—Balss 1957: 1661.— Serène 1964a: 264; 1968: 92 [in list].—Dai et al. 1986: 365 [in key; incorrectly as Chasmocarcinus ], 387.— Dai & Yang 1991: 393 [in key; incorrectly as Chasmocarcinus ], 417.—Ng et al. 2008: 76 [in list].— De Grave et al. 2009: 32 [in list].

Type species. Chasmocarcinops gelasimoides Alcock, 1900 (by monotypy, gender feminine).

Diagnosis. Carapace ( Fig. 9 ) subtrapezoidal, high; front bilobed, with deep median cleft; anterolateral margins arcuate, with conspicuous granules particularly on anterior, posterior margins; long setae; deep, wide sulcus along each mesogastric, cardiac regions. Epistome ( Fig. 23 I, J) sunken, narrow; posterior margin delimited, triangular median lobe with shallow fissure, semicircular lateral margins without visible fissures. Conspicuously raised, granular pterygostome. Orbit ( Fig. 23 I, J) long; eye peduncle filling orbit, short, immobile (or sessile); cornea reduced, with reduced pigmentation. Third maxillipeds ( Fig. 30 E, F) not filling buccal cavern when closed; merus elongated, narrower than ischium, anterior portion subtriangular, outer margin nearly straight, anteroexternal angle not produced; ischium elongated, about twice as long as merus. Chelipeds ( Figs. 9 ; 40A‒D) subequal in length, with short setae except propodus of major chela of male; major chela of large males ( Fig. 40 A) with conspicuously curved, thin fingers, smooth except large teeth near tips, inner surface with prominent swelling near base of fingers in large adults; fingers of minor chela ( Fig. 40 B, D) subcircular in cross-section, not laterally flattened, gently tapering to tip, scissor-like, cutting margins with distinct sharp teeth; fingers of both chelipeds of female ( Fig. 9 C, F, H) slender, armed with sharp (some obtuse) teeth. Inner margin of cheliped carpus smooth ( Fig. 9 ). Ventral margins of cheliped merus of female with large tubercles. Meri of ambulatory legs ( Fig. 9 ) with small teeth along dorsal, ventral margins, dorsal margin of male P5 unarmed; long to short setae along margins of carpi, propodi, dactyli, P5 merus, dorsal margins of P2–P4 meri. Fused thoracic sternites 1, 2 ( Fig. 51 F) triangular, short; fused thoracic sternites 3, 4 ( Figs. 51 F; 86F; 90F) relatively broad; semi-circular, granular ridge along middle portion of thoracic sternites 3, 4 of female. Male thoracic sternite 8 ( Fig. 58 F) short, quadrate; “supplementary plate” short, longer at rounded outer margin; structures tightly appressed with most of penis concealed. Male pleon ( Figs. 51 F; 58F) with lateral margins of somite 6 straight, margins of fused somites 3–5 nearly straight; telson proportionally long. G1 ( Fig. 70 A–D) stout, distal segment curved, with spinules, distal segment slightly curved outwards. G2 ( Fig. 70 E) about one third G1 length, slightly curved, slender, distal segment long, slightly curved. Somites of female pleon ( Fig. 86 F) short, with convex lateral margins; telson proportionally elongated. Sterno-pleonal cavity of female ( Fig. 90 F) moderately deep, vulvae close together in flat portion of thoracic sternite 6.

Distribution. Indo-West Pacific region: Eastern Indian and western Pacific oceans.

Figures

FIGURE 9. Overall dorsal view, chela and buccal area of Chasmocarcinops gelasimoides. A, B, Andaman Sea: male (after Alcock 1899 a: pl. 62 fig. 3, 3 a); C, D, Andaman Sea: female (after Alcock 1899 a: pl. 62 fig. 2, 2 a); E, Andaman Sea: male 8.8 × 9.5 mm (PMBC 16849); F, Andaman Sea: female 11.5 × 12.4 mm (PMBC 16894); G, Singapore: male 9.5 × 10.3 mm (ZRC 2000.1341); H, Singapore: female 9.3 × 10.6 mm (ZRC 2013.1411).

FIGURE 23. Frontal view of cephalothorax of species of Camatopsis and Chasmocarcinops. A, Camatopsis rubida, Andaman Sea: male 4.2 × 4.5 mm (ZMUC CRU 20539); B, Camatopsis rubida, Australia: male 8.3 × 8.5 mm (NMV J 54591); C, Camatopsis africana n. sp., Madagascar: holotype male 5.7 × 6.9 mm (MNHN-IU- 2010 - 1574); D, Camatopsis leptomerus n. sp., Philippines: holotype male 10.5 × 11.3 mm (NMCR); E, Camatopsis leptomerus n. sp., Philippines: paratype female 3.4 × 4.0 mm (ZRC 2015.159); F, Camatopsis minor n. sp., Indonesia: holotype male 3.6 × 4.3 mm (NNM-ZMA); G, Camatopsis thula n. sp., Taiwan: holotype male 8.9 × 9.3 mm (ZRC 1999.0662); H, Camatopsis valida n. sp., Fiji: holotype male 3.6 × 4.9 mm (MNHN-IU- 2013 - 9067); I, Chasmocarcinops gelasimoides, Andaman Sea: male 8.8 × 9.5 mm (PMBC 16849); J, Chasmocarcinops gelasimoides, Singapore: male 9.5 × 10.3 mm (ZRC 2000.1341).

FIGURE 30. Third maxilliped of species of Camatopsis and Chasmocarcinops. A, Camatopsis rubida, Australia: male 8.3 × 8.5 mm (NMV J 54591); B, Camatopsis africana n. sp., Madagascar: holotype male 5.7 × 6.9 mm (MNHN-IU- 2010 - 1574); C, Camatopsis leptomerus n. sp., Philippines: holotype male 10.5 × 11.3 mm (NMCR); D, Camatopsis thula n. sp., Taiwan: holotype male 8.9 × 9.3 mm (ZRC 1999.0662); E, Chasmocarcinops gelasimoides, Andaman Sea: male 8.8 × 9.5 mm (PMBC 16849); F, Chasmocarcinops gelasimoides, Singapore: male 9.5 × 10.3 mm (ZRC 2000.1341).

FIGURE 40. Chelae of species of Chasmocarcinops and Hephthopelta. A, B, Chasmocarcinops gelasimoides, Andaman Sea: male 8.8 × 9.5 mm (PMBC 16849); C, D, Chasmocarcinops gelasimoides, Singapore: male 9.5 × 10.3 mm (ZRC 2000.1341); E, F, Hephthopelta lugubris, Australia: male 7.9 × 8.3 mm (NMV J 61081); G, H, Hephthopelta occidentalis n. sp., Madagascar: holotype male 6.1 × 6.6 mm, with sacculinid (MNHN-IU- 2010 - 1031).

FIGURE 51. Anterior thoracic sternum and male pleon of species of Camatopsis and Chasmocarcinops. A, Camatopsis rubida, Australia: male 8.3 × 8.5 mm (NMV J 54591); B, Camatopsis africana n. sp., Madagascar: holotype male 5.7 × 6.9 mm (MNHN-IU- 2010 - 1574); C, Camatopsis leptomerus n. sp., Philippines: holotype male 10.5 × 11.3 mm (NMCR); D, Camatopsis thula n. sp., Taiwan: holotype male 8.9 × 9.3 mm (ZRC 1999.0662); E, Camatopsis valida n. sp., Fiji: holotype male 3.6 × 4.9 mm (MNHN-IU- 2013 - 9067); F, Chasmocarcinops gelasimoides, Singapore: male 9.5 × 10.3 mm (ZRC 2000.1341).

FIGURE 58. Thoracic sternites 7 and 8 and male pleon of species of Camatopsis and Chasmocarcinops. A, Camatopsis rubida, Australia: male 8.3 × 8.5 mm (NMV J 54591); B, Camatopsis africana n. sp., Madagascar: holotype male 5.7 × 6.9 mm (MNHN-IU- 2010 - 1574); C, Camatopsis leptomerus n. sp., Philippines: holotype male 10.5 × 11.3 mm (NMCR); D, Camatopsis thula n. sp., Taiwan: holotype male 8.9 × 9.3 mm (ZRC 1999.0662); E, Camatopsis valida n. sp., Fiji: paratype female 3.5 × 4.3 mm (MNHN-IU- 2013 - 9467); F, Chasmocarcinops gelasimoides, Singapore: male 9.5 × 10.3 mm (ZRC 2000.1341).

FIGURE 70. Gonopods of Chasmocarcinops gelasimoides. A, Andaman Sea: male 8.8 × 9.5 mm (PMBC 16849); B ‒ E, Singapore: male 9.5 × 10.3 mm (ZRC 2000.1341). A, B, ventral view of left G 1; C, ventral view of distal part of left G 1; D, dorsal view of distal part of left G 1; E, left G 2. Scales: A, B, E = 0.5 mm; C, D = 0.1 mm.

FIGURE 86. Female thoracic sternum and pleon of species of Camatopsis and Chasmocarcinops. A, Camatopsis rubida, Australia: female 6.0 × 7.0 mm (NMV J 61082); B, Camatopsis africana n. sp., Mozambique Channel: paratype female 9.4 × 11.0 mm (MNHN-IU- 2008 - 10288); C, Camatopsis leptomerus n. sp., Philippines: paratype female 12.7 × 13.2 mm (ZRC 2015.170); D, Camatopsis thula n. sp., Taiwan: paratype female 7.1 × 7.6 mm (ZRC 2009.0348); E, Camatopsis minor n. sp., Indonesia: paratype female 4.0 × 4.9 mm (NNM-ZMA); F, Chasmocarcinops gelasimoides, Singapore: female 9.3 × 10.6 mm (ZRC 2013.1411).

FIGURE 90. Vulvae of species of Camatopsis and Chasmocarcinops. A, Camatopsis rubida, Australia: female 6.0 × 7.0 mm (NMV J 61082); B, Camatopsis africana n. sp., Mozambique Channel: paratype female 9.4 × 11.0 mm (MNHN-IU- 2008 - 10288); C, Camatopsis leptomerus n. sp., Philippines: paratype female 12.7 × 13.2 mm (ZRC 2015.170); D, Camatopsis thula n. sp., Taiwan: paratype female 7.1 × 7.6 mm (ZRC 2009.0348); E, Camatopsis valida n. sp., Fiji: paratype female 3.5 × 4.3 mm (MNHN-IU- 2013 - 9467); F, Chasmocarcinops gelasimoides, Singapore: female 9.3 × 10.6 mm (ZRC 2013.1411).