Microtopsis takedai Komai, Ng & Yamada, 2012

Ng, Peter K. L. & Castro, Peter, 2016, Revision of the family Chasmocarcinidae Serène, 1964 (Crustacea, Brachyura, Goneplacoidea), Zootaxa 4209 (1), pp. 1-182 : 85-86

publication ID	https://doi.org/ 10.11646/zootaxa.4209.1.1
publication LSID	lsid:zoobank.org:pub:849BAB5C-464A-4B4A-A586-5742411EDC01
DOI	https://doi.org/10.5281/zenodo.5617207
persistent identifier	https://treatment.plazi.org/id/F16BFB33-FFF7-FFAE-FF6A-FB77FCD5F9C0
treatment provided by	Plazi
scientific name	Microtopsis takedai Komai, Ng & Yamada, 2012
status

Treatment

Microtopsis takedai Komai, Ng & Yamada, 2012 View in CoL

( Figs. 18 View FIGURE 18 A; 27A; 48A, B; 55B; 62A; 80A, B; 81A–F; 88E; 92A)

Microtopsis takedai Komai, Ng & Yamada, 2012: 149 View in CoL , 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 View Materials ), Awa, Nago , Okinawa, 13 m, scuba diving, Y. Yamada coll., 0 2.01.2011.

Diagnosis. Carapace ( Fig. 18 View FIGURE 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 View FIGURE 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 View FIGURE 27 A; Komai et al. 2012: fig. 2B) filling orbit, long, mobile; cornea reduced, pigmented. Third maxillipeds ( Fig. 80 View FIGURE 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 View FIGURE 80 A; Komai et al. 2012: 3A). Chelipeds ( Figs. 18 View FIGURE 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 View FIGURE 48 B; Komai et al. 2012: figs. 3D, 5A, B), largest chela of male ( Fig. 48 View FIGURE 48 A; Komai et al. 2012: 3B) high, with broad teeth on pollex, dentate dactylus. Inner margin of cheliped carpus ( Fig. 18 View FIGURE 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 View FIGURE 55 B; Komai et al. 2012: fig. 2D) broadly triangular, proportionally long, short; fused sternites 3, 4 ( Figs. 88 View FIGURE 88 E; 92A; Komai et al. 2012: fig. 2E) relatively broad. Male pleon ( Figs. 55 View FIGURE 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 View FIGURE 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 View FIGURE 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 View FIGURE 88 E; Komai et al. 2012: fig. 5D) with convex lateral margins; telson proportionally short. Sterno-pleonal cavity of female ( Fig. 92 View FIGURE 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.

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 View FIGURE 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.