Xenophidion

Xenophidion is a genus of snakes first described in 1995, and the only genus of the monotypic family Xenophidiidae.^[1] Commonly referred to as spinejaw snakes, this genus is found in Borneo and peninsular Malaysia.

Xenophidion
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Suborder:	Serpentes
Superfamily:	Bolyerioidea
Family:	Xenophidiidae Wallach & Günther, 1998
Genus:	Xenophidion Günther & Manthey, 1995

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 that has a spiny palatine process. They also lack any pelvic girdle vestiges, a left lung, or a coronoid bone.^[2] In 2004, cytochrome b sequencing suggested a sister relationship of Xenophidion to Bolyeriidae from Mauritius.^[3] 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.^[4] They are likely fossorial and may be under severe threat from palm oil agriculture.

Species

• Xenophidion acanthognathus Günther & Manthey, 1995
• Xenophidion schaeferi Günther & Manthey, 1995