Is the horned pitviper Ceratrimeresurus shenlii Liang and Liu, 2003 from China a valid Protobothrops?

Previous records of horned pitvipers from Vietnam and China are reviewed and the phylogenetic placement of four snakes from two sites in Tianjingshan Forest, China (Ruyan County, Guangdong Province; 24°43′N, 113°03′E, 563 m a.s.l.; 24°43′N, 113°02′E, 585 m a.s.l.) is examined. Using mitochondrial DNA sequence data (12S, 16S, ND4, cyt b; 2306 bp) and Bayesian and Maximum Likelihood analyses, the Tianjingshan pitvipers are revealed as sister to Protobothrops cornutus with a differentiation resembling those of P. flavoviridis and P. tokarensis. This indicates a close relationship with P. cornutus and suggests that Ceratrimeresurus shenlii Liang and Liu, 2003, previously considered a junior synonym of P. cornutus (Smith, 1930), could be a valid subspecies of P. cornutus or a recently split distinct species. However, further studies and samples from intermediate localities are needed to decide whether the observed differentiation reflects a pattern of isolation-by-distance or a phylogeographic, and thus perhaps taxonomically relevant, break. [ABSTRACT FROM AUTHOR]