Pseudoxenodontinae is a small subfamily of colubroid

snakes Snakes are elongated, limbless, carnivorous reptiles of the suborder Serpentes . Like all other squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales. Many species of snakes have skulls with several more joi ...

, sometimes referred to as a family (Pseudoxenodontidae). They are found in southern and southeastern Asia, from northeast India to southern China (including Taiwan) and south into Indonesia as far east as

Wallace's Line The Wallace Line or Wallace's Line is a faunal boundary line drawn in 1859 by the British naturalist Alfred Russel Wallace and named by English biologist Thomas Henry Huxley that separates the biogeographical realms of Asia and Wallacea, a tr ...

. There are 10 species in 2 genera. Most are very poorly known, such that Pseudoxenodontinae is one of the most poorly known groups of snakes. Pseudoxenodontine snakes are small to medium-sized egg-laying snakes. Shared features of the

hemipenes A hemipenis (plural hemipenes) is one of a pair of intromittent organs of male squamates (snakes, lizards and worm lizards). Hemipenes are usually held inverted within the body, and are everted for reproduction via erectile tissue, much like ...

between ''Pseudoxenodon'' and ''Plagiopholis'' first described in 1987, were later backed up by evidence from DNA in the early-2010s. There are many differences between the two genera. ''Pseudoxenodon'' seem to be found along streams in wet forests, whereas ''Plagiopholis'' are apparently found in grasses, bushes, and riprap. ''Pseudoxenodon'' eat frogs and lizards and ''Plagiopholis'' eat earthworms. ''Plagiopholis'' (20 to 40 cm total length) are smaller than ''Pseudoxenodon'' (50 to 170 cm in total length). At least two species of ''Pseudoxenodon'' (''P. bambusicola'' and ''P. macrops'') have impressive threat displays, including flashing boldly banded ventral patterning and bright yellow coloration, spreading a hood, and playing dead. ''Plagiopholis'' have no enlarged teeth, but ''Pseudoxenodon'' have the two posterior-most maxillary teeth enlarged. No bites to humans are known. In spite of these differences, several studies have placed these two genera in a group together at or near the base of either

Dipsadinae Dipsadinae is a large subfamily of colubroid snakes, sometimes referred to as a family (Dipsadidae). They are found in most of the Americas, including the West Indies, and are most diverse in South America. There are more than 700 species. Dips ...

Natricinae The Natricinae are a subfamily of colubroid snakes, sometimes referred to as a family (Natricidae). The subfamily comprises 37 genera. Members include many very common snake species, such as the European grass snakes, and the North American wa ...

, whereas one study suggested that at least ''Pseudoxenodon'' is nested within Dipsadidae and represents a reverse west-to-east colonization across the

Bering Land Bridge Beringia is defined today as the land and maritime area bounded on the west by the Lena River in Russia; on the east by the Mackenzie River in Canada; on the north by 72 degrees north latitude in the Chukchi Sea; and on the south by the tip of ...

, from South America to Asia.

Genera

* ''

Plagiopholis ''Plagiopholis'' is a genus of snakes in the family Colubridae. The genus is native to Asia. General Facts The species of the genus ''Plagiopholis'' are found in Southeast Asia, China and Taiwan. The snakes of this genus are mountainous spec ...

'' Boulenger, 1893, 4 species of mountain snakes * '' Pseudoxenodon'' Boulenger, 1890, 6 species of bamboo snakes, also sometimes called false cobras

References

{{Taxonbar, from=Q144572 Tetrapod subfamilies Colubrids