The King ratsnake, Elaphe carinata (Günther, 1864), belongs to the family Colubridae , and ranges through Vietnam, Japan and China. In China, this species is widely distributed across a large region from western Yunnan (Gongshan County.) in the west to Shanghai in the east, and from northern Guangdong in the south to Hebei in the north. E. carinata is a large snake with adults ranging from 1500 mm to 2000 mm in total length. This snake occupies a variety of habitats at elevations ranging between 100 and 2500 m above sea level.

Based on morphological character comparisons and molecular phylogenetic reconstruction, we assessed the validity of the ratsnake subspecies Elaphe carinata deqenensis. Phylogenetic relationships inferred from fragments of two mitochondrial genes (ND2 and ND4) and one nuclear gene (c-mos) revealed a well-supported and minimally divergent sister relationship between putative E. c. deqenensis and E. c. carinata.

Morphological comparisons indicated that all diagnostic characters proposed in the original description of E. c. deqenensis are unable to separate this taxon from E. c. carinata. On the basis of these preliminary investigations, researchers provisionally suggest that E. c. deqenensis is not a valid subspecies, and should henceforth be treated as a synonym of E. c. carinata.

Researchers from Yibin University and Chengdu Institute of Biology of CAS cooperated to study this research.