Revision of the family Chasmocarcinidae Serène, 1964 (Crustacea, Brachyura, Goneplacoidea) Author Ng, Peter K. L. Author Castro, Peter text Zootaxa 2016 4209 1 1 182 journal article 37321 10.11646/zootaxa.4209.1.1 2de5b7bf-3975-458a-b200-07ec69f4e013 1175-5326 272646 849BAB5C-464A-4B4A-A586-5742411EDC01 Microtopsis takedai Komai, Ng & Yamada, 2012 ( Figs. 18 A; 27A; 48A, B; 55B; 62A; 80A, B; 81A–F; 88E; 92A) Microtopsis takedai Komai, Ng & Yamada, 2012: 149 , figs. 1‒5 [type localilty: Japan, Ryukyu Is.]. Type material . Holotype male (2.4 × 3.1 mm ) (CBM-ZC 10491), Japan , Ryukyu Is , Okinawa , Nago. Paratype: female (2.8 × 3.4 mm ) (CBM-ZC 10492), male and female (ZRC 2012.0146), type locality. Other material examined . Japan . 1 male (damaged) , 1 female (3.6 × 2.7 mm ) ( ZRC 2012.0146 ), Awa , Nago , Okinawa , 13 m , scuba diving, Y. Yamada coll., 0 2.01.2011. Diagnosis . Carapace ( Fig. 18 A; Komai et al. 2012 : figs. 1; 2A; 2B) subtrapezoidal, 1.2‒1.3 wider than long; front nearly straight; anterolateral margins arcuate, minutely dentate, without distinct lobes or teeth; dorsal surface almost smooth except for minute granules on lateral surfaces. Epistome ( Fig. 27 A; Komai et al. 2012 : fig. 2C) slightly depressed; posterior margin with widely semicircular median lobe with median fissure, semicircular lateral margins without fissures. Eye peduncle ( Fig. 27 A; Komai et al. 2012 : fig. 2B) filling orbit, long, mobile; cornea reduced, pigmented. Third maxillipeds ( Fig. 80 A; Komai et al. 2012 : fig. 3A) not filling buccal cavern when closed; merus subcircular, anteroexternal angle rounded, narrower than ischium; ischium quadrate, widened inner margin, about same length as merus ( Fig. 80 A; Komai et al. 2012 : 3A). Chelipeds ( Figs. 18 A; 48A, B; Komai et al. 2012 : figs. 3B, D; 5A, B) subequal in length, slightly dissimilar in female, heteromorphic in males; cutting margins of both chelipeds of females, minor in males with dense row of short setae ( Fig. 48 B; Komai et al. 2012 : figs. 3D, 5A, B), largest chela of male ( Fig. 48 A; Komai et al. 2012 : 3B) high, with broad teeth on pollex, dentate dactylus. Inner margin of cheliped carpus ( Fig. 18 A; Komai et al. 2012 : 3C, E) with short tooth. Ventral surface of cheliped merus with short row of low microscopic tubercles on posterior outer margin in both sexes. Meri of ambulatory legs unarmed; P5 merus 0.5 cl in paratype female. Fused thoracic sternites 1, 2 ( Fig. 55 B; Komai et al. 2012 : fig. 2D) broadly triangular, proportionally long, short; fused sternites 3, 4 ( Figs. 88 E; 92A; Komai et al. 2012 : fig. 2E) relatively broad. Male pleon ( Figs. 55 B; 62A; 80B; Komai et al. 2012 : fig. 2D; 2H) with lateral margins of somite 6, fused somites 3‒5 convex; telson proportionally short; postero-lateral regions slightly swollen. Sterno-pleonal cavity deep. Press-button for pleonal holding ( Komai et al. 2012 : fig. 2G) as small, short tubercle posterior to thoracic sternal suture 4/5 near edge of sterno-pleonal cavity. G1 ( Fig. 81 A‒E; Komai et al. 2012 : fig. 4A‒E) stout, short, median part distinctly twisted, distal part slightly twisted, distal segment with short spinules. G2 ( Fig. 81 F); Komai et al. 2012 : fig. 4F) slightly curved, slender, pointed distal segment, almost as long as G1. Somites of female pleon ( Fig. 88 E; Komai et al. 2012 : fig. 5D) with convex lateral margins; telson proportionally short. Sterno-pleonal cavity of female ( Fig. 92 A; Komai et al. 2012 : fig. 5C) moderately deep, vulvae far apart from each other on outer margins of cavity close to suture 5/6. FIGURE 18. Overall dorsal view of species of Microtopsis . A, M. takedai , Japan: paratype female 3.6 × 2.7 mm (ZRC 2012.0146); B, M. teschi n. sp. , Indonesia: holotype male 1.5 × 2.1 mm (NNM-ZMA); C, M. teschi n. sp. , Indonesia: paratype male 1.5 × 1.9 mm (NNM-ZMA). Remarks . The third maxilliped merus is incorrectly described and illustrated by Komai et al . (2012 : fig. 3A). It is not subtriangular, but rather more subcircular, with the anterior margin even rather than distinctly produced. The “supplementary plate” ( Fig. 62 A), which is about the same short length along thoracic sternite 8 and reaches episternite 7 in the paratype male (ZRC 2012.0146), is not as narrow and not reaching the posterior edge of the pleon as depicted in the holotype by Komai et al . (2012 : fig. 3E). Distribution . Known only from Japan . Depth: 13 m .