Disentangling the Pelodiscus axenaria complex, with the description of a new Chinese species and neotype designation for P. axenaria (Zhou, Zhang & Fang, 1991)

Abstract

We describe a new species from the Pelodiscus axenaria complex from Hunan and Jiangxi Provinces, China. Also, the application of the name P. axenaria (Zhou, Zhang & Fang, 1991) is clarified by designating a neotype for this species. Besides its genetic divergence, the new species differs from all other Pelodiscus species, including the two other taxa constituting the complex (P. axenaria, P. huangshanensis), in the following combination of morphological traits: (1) small adult size, <15 cm carapace length; (2) carapace distinctly keeled, more or less strongly tuberculated, usually olive clay-coloured and adorned with greenish black marbling; (3) plastron yellowish white, typically immaculate except for a blurred-edged blotch behind each axilla that does not extend to the entoplastron and some slight black suffusion along its anterior border; (4) underside of the leathery margin of the carapace with varying amounts of dark pigmentation; (5) head olive clay-coloured with numerous black splotches; (6) chin grey brown with pale stipples, throat dark grey, finely spotted with black; (7) neck with a wide yellow lateral band stretching from the tympanum posteriorly, which tends to fade with age; (8) entoplastron boomerang-shaped, the amount of bending of the transverse bar between the two posteriolaterally directed rami >90°.