''Xenophidion'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of snakes first described in 1995, and the only genus of the monotypic

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Xenophidiidae.. Commonly referred to as spinejaw snakes, this genus is found in

Borneo Borneo (; id, Kalimantan) is the third-largest island in the world and the largest in Asia. At the geographic centre of Maritime Southeast Asia, in relation to major Indonesian islands, it is located north of Java, west of Sulawesi, and eas ...

and peninsular

Malaysia Malaysia ( ; ) is a country in Southeast Asia. The federation, federal constitutional monarchy consists of States and federal territories of Malaysia, thirteen states and three federal territories, separated by the South China Sea into two r ...

Morphology and classification

This genus is taxonomically and phylogenetically challenging to classify, as these snakes possess several morphological traits that distinguish them from all other snake species; head scales with numerous sensory papillae, large prefrontal scales, and an upper jaw which has a spiny palatine process. They also lack any pelvic girdle vestiges, a left lung, or a coronoid bone. In 2004, cytochrome b sequencing suggested a sister relationship of ''Xenophidion'' to

Bolyeriidae :''Common names: Mauritius snakes, Round Island boas, splitjaw snakes.'' The Bolyeriidae are a family of snakes native to Mauritius and a few islands around it, especially Round Island. They also used to be found on the island of Mauritius, but ...

from

Mauritius Mauritius ( ; french: Maurice, link=no ; mfe, label=Mauritian Creole, Moris ), officially the Republic of Mauritius, is an island nation in the Indian Ocean about off the southeast coast of the African continent, east of Madagascar. It incl ...

. Similar to ''Boyleriidae'', spinejaw snakes have a jointed maxilla.

Diet, reproduction, and habitat

Very little is known about this genus. Specimen dissection has revealed the presence of a partially digested skink and an oviparous mode of reproduction, but male specimens have not yet been identified.Xenophidion: The Snake with the Mystery Penis
snakesarelong.blogspot.com (28 September 2016) They are likely fossorial and may be under severe threat from palm oil agriculture.

Species

* ''

Xenophidion acanthognathus ''Xenophidion acanthognathus'', also known as the Bornean spine-jawed snake is a species of snake in the monotypic family Xenophidiidae. It is found in Sabah and Sarawak on the island of Borneo, Malaysia Malaysia ( ; ) is a country in S ...

'' Günther & Manthey, 1995 * ''

Xenophidion schaeferi ''Xenophidion schaeferi'', also known commonly as the Malayan spinejaw snake or Schäfer's spiny-jawed snake, is a species of snake in the monotypic family Xenophidiidae. The species is endemic to Malaysia. Etymology The specific name, ''schae ...

'' Günther & Manthey, 1995

References

{{Taxonbar, from=Q933635 Snake families Snake genera Alethinophidia