Ponotus shirahamensis, Karasawa & Ohara, 2009

Karasawa, Hiroaki & Ohara, Masaaki, 2023, Validation of Ponotus shirahamensis Karasawa & Ohara, a raninid crab from the Miocene Tanabe Group of central Japan, Zootaxa 5270 (2), pp. 345-346 : 345-346

Ponotus shirahamensis n. sp.

Ponotus shirahamensis Karasawa & Ohara 2009: 200 , figs. 1.1–5. [unavailable].

Type material. HOLOTYPE: WMNH-Ge-112012007, carapace and right cheliped from the Shirahama Formation of the lowermost Middle Miocene Tanabe Group exposed in beach of Migusazaki , Tsubaki , Shirahama-cho , Wakayama Prefecture (33°37′7.2′′N, 135°23′22.1′′E) . PARATYPES: WMNH- Ge-112012006, thoracic sternum, chelipeds, and pereiopods; WMNH-Ge-112012024, carapace and right cheliped; MFM83067, carapace and chelipeds; MFM83068, carapace and chelipeds; all from the same locality as holotype.

Diagnosis. Carapace moderate-sized for Notopodinae, ovoid, much longer than wide. Fronto-orbital margin wide, about 75% maximum width; rostrum simple, short, broadly triangular, with median dorsal carina; orbital margin with shallow orbital fissure outside intra-orbital spine and 2 orbital spines; intra-orbital spine slightly directed anterolaterally; outer-orbital spine directed anteriorly; anterolateral margin slightly sinuous with short hepatic spine; posterolateral margin gently convex, weakly rimmed; posterior margin slightly convex, weakly rimmed; dorsal surface strongly convex transversely, gently convex longitudinally, regions not defined, anterior surface with coarse granules, anterolateral portion rugose, and other surfaces punctate; transverse ridge between hepatic spines absent; weak median longitudinal carina present. Chelipeds similar in size and shape; lateral surfaces of merus, carpus, and propodus terraced ridges; propodus subtriangular, compressed laterally, about as long as high; fixed finger short; dactylus narrow, long, strongly curved ventrally, without teeth or spines on dorsal and occlusal margins.

Etymology. From the occurrence of the specimens in Shirahama-cho.

Remarks. A full description and figures of Ponotus shirahamensis are given by Karasawa & Ohara (2009).