Mariaplax sinensis Rahayu &amp; Ng 2014, new species
Creators: name: Rahayu, Dwi Listyo
name: Ng, Peter K. L.
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Hexapodidae
Mariaplax
Mariaplax sinensis

description: <i>Mariaplax sinensis,</i> new species (Figs. 48, 49) <b>Material examined.</b> Holotype: male (7.5 × 5.2 mm) (IOCAS), station 21, Bohai Gulf, very close to 38°40'N 117°50'E, to 7 m depth, soft mud, coll. D. Sun &amp; G. Lin, 27 August 1979. <b>Diagnosis.</b> Carapace subquadrate, about 1.5 times as broad as long, dorsal surface granulated; regions indistinct, with shallow median H-shaped depression (Fig. 48A). Anterolateral margin arcuate; posterolateral margin with angled prominence over base of posterior pereopods (Figs. 48A, 49A). Eye slightly movable, small, cornea pigmented, wider than peduncle. Pterygostomial region with row of oblique striae. Third maxillipeds broad (Figs. 48B, 49D), without distinct gap between them; ischium longer than broad, much longer than merus, mesial margin straight, combined length of dactylus, propodus and carpus shorter than that of merus and ischium; exopod narrow, 0.4 width of ischium, slightly granular, flagellum well developed. Chelipeds asymmetrical; both chelae (Fig. 48C) with gap when fingers closed; palm slightly longer than wide, surface finely tuberculate. P2–P4 tomentose, surfaces granulated (Fig. 48A); merus of P4 three times as long as broad, shallow longitudinal groove on outer surface medially; dactylus of P4 gently upcurved. Male thoracic sternum broad (Figs. 48B, 49B, C), surface finely granular; sternites 1 and 2 fused, separated from sternite 3 by distinct ridge; sternite 3 separated from sternite 4 by distinct ridge; wide transverse groove extends obliquely from edge of sternoabdominal cavity, not reaching base of chelipeds (Figs. 48B, 49B); sternite 8 exposed, subrectangular, slightly longer than abdominal somite 1; sternoabdominal cavity reaching midlength of thoracic sternite 4 (Fig. 49C). Male abdomen relatively narrow (Fig. 49E), surface granular, somites 1 and 2 free; somites 3–5 fused, lateral margin slightly arched; somite 6 slightly shorter than somites 3–5, lateral margin expanded into blunt triangular projection subproximally; telson subtriangular, distal margin rounded (Figs. 48B, 49E). G1 slender (Fig. 49F, G), S-shaped, distal part tapered, sparse short setae present laterally and mesially; row of minute spines on mesial margin medially; distal part exposed on thoracic sternal groove, not concealed under abdomen. <b>Colour.</b> Not known. <b>Etymology.</b> Named after the type locality, China. <b>Remarks.</b> <i>Mariaplax anfracta</i>, <i>M. propinqua</i>, new species, and <i>M. sinensis</i>, new species, share the same general shape of G1: S-shaped with a long and bent distal part. The differences between these three species are as follow: the male anterior thoracic sternum in <i>M. sinensis</i> is proportionately much wider (Fig. 49B, C) (versus Figs. 23B, C, 44A, 45C, D), and the presence of row of small spines on the G1 medial lateral margin in <i>M. sinensis</i> (Fig. 49F, G) (no spines present in <i>M. anfracta</i>, Fig. 23F, G; and three large spines in <i>M. propinqua</i>, Fig. 45I, J). Although <i>M. chenae</i> also possesses a row of minute spines at the middle of the lateral margin of the G1, the shape of the G1 is different, being relatively stouter and distally twisted (Fig. 25I, J) (versus more slender, tapering, and only slightly twisted distally in <i>M. sinensis</i>, Fig. 49F, G). <b>Type locality.</b> Bohai Gulf, East China Sea. <b>Distribution.</b> East China Sea. Subtidal, 7 m.
description: Published as part of <i>Rahayu, Dwi Listyo &amp; Ng, Peter K. L., 2014, New genera and new species of Hexapodidae (Crustacea, Brachyura) from the Indo-West Pacific and east Atlantic, pp. 396-483 in Raffles Bulletin of Zoology 62</i> on pages 455-457, DOI: 10.5281/zenodo.5353945