Genus Cardisoma Latreille, 1828 sensu stricto

TYPE SPECIES. — Cardisoma guanhumi Latreille, in Latreille, Le Peletier, Serville & Guérin, 1828 .

OTHER SPECIES. — Cardisoma armatum Herklots, 1861; C. carnifex (Herbst, 1796); C. crassum Smith, 1870 (not examined).

REMARKS

Two species traditionally assigned to Cardisoma, C. hirtipes (see Appendix) and C. rotundum, are hereby assigned to a new genus Tuerkayana n. gen., to which are added Discoplax celeste of Ng & Davie (2012) and D. magna of Ng & Shih (2014). The more significant features that characterise Cardisoma sensu stricto are the traditionally used ones that identify the type species C. guanhumi and, in addition, features based on the thoracic sternum.

DIAGNOSIS

Carapace inflated and thick (Fig. 4 A-C: C. guanhumi, C. carnifex, C. armatum, respectively) (Bouchard et al. 2013: fig. 12C, C. carnifex); dorsal surface with regions weakly or hardly demarcated, smooth and without posterolateral striae; anterolateral margin not delimited, unarmed, except for one notch just behind the exorbital angle in C. guanhumi (Rathbun 1918: pl. 106, C. guanhumi; Türkay 1970: fig. 8a, C. guanhumi; Türkay 1973: fig. 7, C. armatum; Türkay 1974a: fig. 11, C. carnifex; Tavares 1989: fig.3, C. guanhumi; Bouchard et al. 2013: fig. 12C, C. carnifex; Rathbun 1918: pl. 108, C. crassum; Diez & Capote 2015: fig. 7K, C. guanhumi). Proepistome prominently dome-shaped (Fig. 6B); suborbital margin entirely joining exorbital tooth; orbit closed laterally by right-angled margin; no suborbital crest (Fig. 6B) (Tavares 1989: fig. 3). Subhepatic and subbranchial areas not striated (Fig. 6B). Setose pterygostomial area usually narrow. Male chelipeds with strong heterochely and heterodonty: major chela very stout; fingers markedly gaping, with one main tooth on both prehensile margins; minor chela narrow, long; fingers elongated, weakly gaping. Thoracic sternum (Fig. 5 D- F) inclined posteriorly, proportionally narrow, especially at level of sternite 4 that is restricted between the P1; anterior sternites forming a proportionally developed plate; sternite 2 semi-ovate, bluntly triangular; no suture 3/4, without lateral trace; sternite 4 anteriorly narrow and long, with more or less concave margins (Türkay 1970: fig. 8b, C. guanhumi; Türkay 1973: fig. 8, C. armatum; Türkay 1974a: fig. 11, C. carnifex); on sternite 4 a thick ridge forming the rim of the sterno-pleonal cavity at level of telson; a thick bridge at level of suture 6/7; sternite 8 rather large, developed medially; no visible portion when pleon is folded; suture 7/8 rather short. Median line on sternites 8, 7 and extending on the whole sternite 6, in front of transverse bridge (Fig. 5E, F) (Ng & Guinot 2001: fig. 3A, C. guanhumi; fig. 3B, C. carnifex; fig. 3C, C. armatum); correspondingly, a median septum at level of sternite 6, higher at level of sternite 7, visible after dissection of C. carnifex . Sterno-pleonal cavity very wide. Pleon elongated, may reach sternite 3; somite 6 narrow and conspicuously elongated; telson (Fig. 5D) (Türkay 1970: fig. 8b, C. guanhumi; 1973: fig. 8, C. armatum; Rathbun 1918: fig. 157, pl. 109, C. crassum); G1 (Türkay 1970: fig. 8b, C. guanhumi; Türkay 1973: fig. 4b, C. carnifex; 1974a: fig.11, C. carnifex). Locking structure absent: no press-button on smooth sternite 5, covered with setae (Fig. 5E) (Guinot 1979; Guinot & Bouchard 1998); no socket on pleonal somite 6, only some remants of a pleonal socket may be discernible in C. carnifex (Köhnk et al. 2017: fig. 20a, b). Male gonopore close to P5 coxo-sternal condyle; penis proximally narrow, then more expanded (Fig. 5F) (Guinot 1979: fig. 54A-C; Guinot et al. 2013: fig. 23A).