Platychirarma, Schubart & Ng, 2020

Schubart, Christoph D. & Ng, Peter K. L., 2020, Revision of the intertidal and semiterrestrial crab genera Chiromantes Gistel, 1848, and Pseudosesarma Serène & Soh, 1970 (Crustacea: Brachyura: Sesarmidae), using morphology and molecular phylogenetics, with the establishment of nine new genera and two new species, Raffles Bulletin of Zoology 68, pp. 891-994 : 936-938

Platychirarma , new genus

Type species. Sesarma büttikoferi De Man, 1883 , by present designation. Gender neuter.

Diagnosis. Carapace trapezoidal, distinctly broader than long; frontal margin slightly bilobed, gently deflexed, wider than carapace margin; lateral margins of carapace almost straight, entire in adults, posterolateral part prominently converging; regions of carapace demarcated; postfrontal and epigastric crests separated by relatively shallow grooves, margin relatively sharp, almost straight, appearing contiguous; basal articles of antenna and antennules separated by septum; dorsal margin of palm without longitudinal pectinated ridge, inner surface not swollen, without granulated ridge, outer surface of palm and pollex almost flat, smooth, outer margin of palm with prominent elbow-like projection; dorsal margin of chelipedal dactylus lined with irregularly arranged small granules of various sizes; inner margin of the chelipedal merus with distal part expanded, wing-like; inner surfaces of first to third ambulatory coxae with only scattered short setae between them, not arranged into dense tufts; male thoracic sternites 2–4 relatively broader, suture between sternites 3 and 4 distinct; male sternopleonal cavity reaching three-quarters length of sternite 4 to just before anterior margin of sternite 2; male thoracic sternite 5 smooth, without depression on anterior part; male pleonal somite 6 proportionately broader, telson more rounded; G1 slender, distal chitinous part elongate, subspatuliform. Vulva on anterior part of sternite 6, anterior edge presses against sternite 5; anterior and posterior sternal vulvar covers low, opening short, cylindrical, projecting, directed obliquely anteriorly.

Etymology. The genus name is derived from the characteristic flattened outer surface of the chelae of the type species, in combination with the genus name Sesarma . The gender is neuter.

Included species. Sesarma büttikoferi De Man, 1883 .

Remarks. See earlier discussion for Trapezarma , new genus.