The complete mitochondrial NADH dehydrogenase subunit 2(ND2) gene sequences of two species of Thermophis, T. baileyi and T. zhaoermii, were sequenced and compared to those of 86 sequences from other snakes(74 from Caenophidia and 12 from Henophidia). By using Bayesian inference(BI) and maximum likehood(ML) approaches, Thermophis was demonstrated as the sister group to the North American relicts of Dipsadinae, and rooted in Central and South American members of this subfamily. The results suggest that the closest relatives of Thermophis are the North American relicts, and thus support the hypothesis for an Asian-North American origin of xenodontine snakes as suggested by Vidal et al.(2000). Extensive sampling of Asian snakes and American dipsadines is needed to further test this hypothesis in the future.
The snakes comprising the monophyletic group referred to as ratsnakes are found throughout Asia,Europe and the New World.Recently,three snake samples likely belonging to the ratsnakes were collected in Zoige County,Sichuan Province,China.Species identity was difficult to delimit morphologically because the specimens were juveniles and partially damaged.Subsequently,a molecular phylogenetic approach was used.Portions of three mitochondrial genes(cyt b,ND4 and 12S rRNA) were sequenced and analyzed.The results showed that they were sister to the genus Elaphe.Very little genetic variation was found among the three samples.The minimum genetic distances between these samples and those within Elaphe were greater than any currently recognized species within the genus.We conclude that this likely represents a new species within the genus Elaphe.Adult specimens and a morphologic description are needed for further study.
LING ChenLIU ShaoyingHUANG SongFrank T.BurbrinkGUO PengSUN ZhiyuZHAO Jie
Assessment of the relationship between Pseudoxenodon and Dipsadinae has been hampered by lack of adequate samples. In this paper, we conducted phylogenetic analyses using two mitochondrial genes （12S and 16S rRNA） and one nuclear gene （c-mos） from thirteen specimens representing two species of Pseudoxenodon, together with 84 sequences of caenophidians and an outgroup sequence of Boa constrictor. Our study suggests that the Southeast Asian genus, Pseudoxenodon forms a robust genetic subclade within South American xenodontines, indicating that at least one lineage within this genus entered or returned to the Old World （OW） from the New World （NW） across the Beringian Land Bridge during the early Tertiary and the warm mid-Miocene. It also reveals the high intraspecific genomic variation within the populations of Pseudoxenodon macrops, indicating that species diversity of Pseudoxenodon in China is likely underestimated.
Previous phylogenetic analyses of DNA sequence data reveal a likely new species of Elaphe Fitzinger from China,which forms the sister group of all extant Elaphe. One of the three original specimens is crushed and the other two are neonates,which precludes a morphological analysis. Three adult snakes(2 females,1 male) collected from Jiangzha Hot Spring in Zoige County,Sichuan,China on 26 July 2010 now facilitate the species’ description. Mitochondrial DNA nucleotide sequences of cytochrome b(cyt b),NADH dehydrogenase subunit 4(ND4),12S ribosomal RNA(12S rRNA),and cytochrome oxidase subunit 1(CO1) from the adults are identical to sequences from the crashed specimen. Interspecific uncorrected p-distances of partial CO1 gene of 26 sequences from all 11 species of Elaphe,including this new species,are large(8.5–15.2%). This new species is morphologically distinguished from all other species of Elaphe by several characters: 'M'-shaped marking on the supraoculars and adjacent frontal; four parallel series of red-brown spots on the dorsum extending from the neck to the vent; four longitudinal stripes associated with the spots; each spot is usually composed of a whole(or incomplete) red-brown scale with puce borders; spots of each stripe are similar in shape,they occur at relatively regular intervals of one or two scales,and they are slightly red-brown in color; and it has three preoculars,whereas all other species have one or two. Now Elaphe contains 11 species and this discovery highlights the need for continued exploration of temperate regions.
Song HUANGLi DINGFrank T.BURBRINKJun YANGJietang HUANGChen LINGXin CHENYaping ZHANG
