Mindanium cruciatum ( Bürger, 1893 ) Naruse & Ng, 2020

Naruse, Tohru & Ng, Peter K. L., 2020, Revision of the sesarmid crab genera Labuanium Serène and Soh, 1970, Scandarma Schubart, Liu and Cuesta, 2003 and Namlacium Serène and Soh, 1970 (Crustacea: Decapoda: Brachyura: Sesarmidae), with descriptions of four new genera and two new species, Journal of Natural History (J. Nat. Hist.) 54 (7 - 8), pp. 445-532 : 500-503

Mindanium cruciatum ( Bürger, 1893) , comb. nov.

( Figures 27 , 28 )

Sesarma cruciatum Bürger, 1893, p. 624 , pl. 21, fig. 6 [type locality: Bislig, E. Mindanao, Philippines].

Sesarma (Sesarma) cruciata: Tesch 1917, p. 142 .

Labuanium cruciatum: Serène and Soh, 1970, p. 401 ; Ng et al. 2008a, p. 221; Ng 2012, p. 266.

Material examined

Holotype. SMF ZMG 623 , female 16.3 × 16.6 mm, Bislig , E. Mindanao , Philippines, coll. C. Semper, 1863–1864.

Redescription of female holotype

Carapace ( Figure 27 (a)) squarish, 1.02 times as wide as long; lateral margins weakly sinuous, convex anteriorly, parallel posteriorly. External orbital tooth blunt, directed anteromesially; 2 epibranchial teeth present, each defined by V-shaped, small incision, lateral margins of these teeth upturned. Dorsal surface slightly convex longitudinally and transversely, regions well defined, glabrous on anterior half, posterolateral to intestinal regions covered with short setae. Front deflexed at anterior margin of postfrontal lobes by more than 90°, distally sloping ventroposteriorly; frontal margin bilobed with wide median concavity, each lobe short, recurved, directed anteriorly, slightly overhanging onto antennular fossae; median concavity ventrally attached by antennular septum ( Figure 28 ). Two pairs of postfrontal lobes ( Figure 27 (a)) aligned anteriorly, anterior edge of lobes reaching beyond frontal margin in dorsal view, overhanging onto front; mesial lobes slightly wider than lateral lobes; 1 swelling on posterior of each postfrontal lobe, lateral swelling placed anterior to mesial swelling. Antennular septum ( Figure 28 ) wide, short. Orbit, in dorsal view ( Figure 27 (a)), tilted J-shaped, median part of supraorbital margins oblique; infraorbital margin cristate, mesial end forming low, triangular inner orbital tooth. No longitudinal ridge on ventral surface of external orbital angle. Suborbital crista straight, granulated, setose. Suborbital, pterygostomial and subhepatic regions with reticulate mat of setae.

Epistome long, posterior margin with 3 triangular lobes, lateral lobes directed anteroventrally, median lobe directed ventrally.

Eye moderately large, with oblique ridge running parallel to border of cornea on anterior surface (when folded); cornea slightly narrower than peduncle. Antennule with rounded basal article. Antenna with wide, ellipsoidal basal article; antenna entering orbit through wide gap between inner orbital tooth and front.

Mxp3 ( Figure 28 ) with relatively stout subtriangular ischium and ovoid merus, leaving short, wide rhomboidal hiatus betweeh them; flagellum of exopod reaching mesial margin of merus.

Chelipeds symmetrical ( Figure 27 (a)). Merus with subtriangular cross section; upper and lower-inner margins keeled, upper margin with low angle subdistally; lower-inner margin lined with granules, produced subdistally. Carpus rhomboidal, with granulated upper surface, inner angle blunt. Palm with weakly convex outer surface ( Figure 27 (b)), granulated except for distal part near bases of fingers, no median protuberance on proximal surface of non-granular part; upper surface ( Figure 27 (c)) granulated, but without row of small granules or ridge; inner surface weakly convex, sparsely granulated; thick rim extending along occlusal margin of immovable finger to dactylar articulation on both outer and inner surfaces, thick rims of both outer and inner surfaces not interrupted near dactylar articulation. Immovable finger almost straight, gradually tapering towards tip, occlusal margin with 3 large teeth, of these, proximal and middle teeth attached with 1 smaller tooth each on proximal and distal side, respectively. Movable finger gently curved, occlusal margin with 4 large teeth and smaller teeth; upper surface weakly granulated on outer half, regularly lined with 6 or 7 granules on proximal half of inner side. Both fingers distally terminating in small corneous tips.

Ambulatory legs ( Figure 27 (a)) long, P3 longest. Meri compressed, subrectangular, distal anterior corner weakly falcate, followed proximally by weak angle; propodi with mixture of long, short setae on inner margin: dactyli straight, short, about half length of propodi.

Pleon not fully expanded. Telson proximally embedded into distal margin of pleonal somite 6.

Colouration

Live colouration not known.

Distribution

Known only from Bislig, east coast of Mindanao, Philippines [type locality].

Figures

Figure 27. Mindanium cruciatum (Bürger, 1893), comb. nov. Holotype, SMF ZMG 623, female 16.3 × 16.6 mm (Mindanao, Philippines). a, habitus, dorsal view; b, right chela, outer view; c, right chela, upper view.

Figure 28. Mindanium cruciatum (Bürger, 1893), comb. nov. Holotype, SMF ZMG 623, female 16.3 × 16.6 mm (Mindanao, Philippines). Anterior part of cephalothorax, anteroventral view.