Pinnixa penultipedalis Stimpson, 1858

Wong, Kingsley J. H., Ng, Peter K. L., Shih, Hsi-Te & Chan, Benny K. K., 2024, Positive association between PTN polymorphisms and schizophrenia in Northeast Chinese Han population., Zoological Studies 63 (38), pp. 141-149 : 121

Pinnixa penultipedalis Stimpson, 1858

Pinnixa penultipedalis Stimpson, 1858b: 54 ; Stimpson 1907: 143; Gee 1926: 163 [list]; Shen 1940a: 230.

Taxonomy: Stimpson (1907), Sakai (1976), Manning and Morton (1987), Naruse and Maenosono (2012).

Type: Probably lost.

Type locality: Hong Kong.

Distribution: East Asia: probably only South China ( Hong Kong) (see Remarks below).

Habitat: Subtidal; among dead shells on muddy substrates in 10 fathoms (about 18.3 m) ( Stimpson 1907).

Remarks: The present species was described from a single female specimen reported by Stimpson (1858b), as having a very broad carapace (2.11 times as broad as long), the dorsal surface being smooth and glossy, and posterior extremity with transverse ridge. The species, however, has never been figured and the types are almost certainly lost. Ortmann (1894: pl. 23(7)) and Shen (1937a: text-fig. 10a) subsequently reported the species from Nagasaki, Japan, and Tsangkou (near Qingdao), Shandong, China, respectively. Both records are considered doubtful: the Japanese record by Ortmann (1894) has a relatively narrower carapace, whereas the record from North China, as indicated in Manning and Morton (1987), apart from a very pronounced transverse cardiac ridge, lacks any transverse ridge on posterior part of the carapace. A recent report of one male specimen from Oki Islands, Sea of Japan by Yamaguchi and Konishi (2004: fig. 1A) shows a specimen with a carapace width to length ratio of approximately 1.95 (4.18 mm × 2.14 mm) and is narrower than in the original description. As suggested by Naruse and Maenosono (2012), we believe none of these records actually represent P. penultipedalis sensu stricto.