Xenophidion acanthognathus GÜNTHER & MANTHEY, 1995
Can you confirm these amateur observations of Xenophidion acanthognathus?
|Higher Taxa||Xenophidiidae, Henophidia, Alethinophidia, Serpentes, Squamata (snakes)|
|Common Names||E: Bornean spine-jawed snake|
|Synonym||Xenophidion acanthognathus GÜNTHER & MANTHEY 1995|
Xenophidion acanthognathus — LAWSON et al. 2004
Xenophidion acanthognathus — WALLACH et al. 2014: 803
|Distribution||Malaysia (Borneo: Sabah, Sarawak)|
Type Locality: Sipitang Dist., Mendolong, Sabah (Borneo).
|Types||Holotype: FMNH 235170|
|Diagnosis||Diagnosis (genus): members of the genus Xenophidion have a combination of character states (Günther & Manthey 1995) including the absence of premaxillary teeth; the presence of small, numerous, approximately equal-sized, aglyphous, weakly recurved palatine, pterygoid, and maxillary teeth; maxillae bearing a long, tapering palatine processes (Processus praefrontales), and a broad, long and thin ectopterygoid processes (Processus pterygoideus); ectopterygoids extending nearly to the middle of the maxillae and almost completely adhering to them; dentary with a bent anterior end and significantly enlarged caniniform tooth; undivided nasals extending ventrally from the midline of the rostrum to near the opening of the mouth; internasals absent, probably fused with prefrontals or nasals; prefrontals greatly enlarged, forming the largest scales on the top of the head; all dorsal head shields extending to the three bordering the prefrontals posteriorly approximately the same modest size, the three bordering the prefrontals are enlarged and possibly fused with the preoculars and the frontal (or parts of it); numerous sensory papillae located on most head shields and especially on the labial scales; loreals absent; suboculars absent; dorsal scales keeled with rounded tips; ventrals narrow; anal plate single; and subcaudals undivided. (Quah et al. 2018).|
Diagnosis: This new species exhibits all of the features that were mentioned in the generic diagnosis. Its specific characteristics are the relatively strong keeling of the body scales (with the exception of the 1-2 rows bordering the ventrals and the posterior caudal scales) and with respect to the following species the greater number of undivided subcaudals (51versus 43); the smaller number of teeth on the palatine (8 versus 10), the pterygoid (13 versus 16), and especially the dentary (12 versus 19), as well as a large yellow-white patch on the neck.
|Comment||Abundance: only known from 2 specimens.|
Wallach & Günther (1998) proposed to establish a new family, Xenophidiidae, for this genus, based on visceral anatomy. The Xenophidiidae are a sister family of the Bolyeriidae (Pyron et al. 2013).
Type species: Xenophidion acanthognathus GÜNTHER & MANTHEY 1995 is the type species of the genus Xenophidion GÜNTHER & MANTHEY 1995.
|Etymology||The Greek word acantha means spine or thorn, the likewise Greek gnathos means jaw. The combination of the two words refers to the long, spiny palatine process on the anterior end of the maxilla, which is a distinguishing characteristic not only of this species, but of the new genus Xenophidion in its entirety.|