Caenophidia

The Caenophidia are a derived clade of alethinophidian snakes, which contains over 80% of all the extant species of snakes.^[1] The largest family is Colubridae, but it also includes at least seven other families,^[1] at least four of which were once classified as "Colubridae" before molecular phylogenetics helped us understand their relationships. It has been found to be monophyletic.^[1]

Caenophidia Temporal range: 84.9–0 Ma PreꞒ Ꞓ O S D C P T J K Pg N Late Cretaceous to Present
Western diamondback rattlesnake (Crotalus atrox)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Suborder:	Serpentes
Clade:	Afrophidia
Clade:	Caenophidia Hoffstetter, 1939
Subclades
†Anomalophioidea †Russellophioidea Acrochordoidea Colubroides
Synonyms
Xenophidia

Although the Caenophidia previously was held to exclude Acrochordidae, researchers have recognized that acrochordids share several traits with the other caenophidians.^[2] Hence Caenophidia is usually considered to comprise Acrochordidae plus more the more derived snakes classified as Colubroidea. Recent molecular studies have also found the families Xenophidiidae and Bolyeriidae to be closely related to caenophidians, forming the sister group to Caenophidia rather than being part of Henophidia.^[3][4]

Below is a phylogeny of the Caenophidia based on analyses from several studies:^[5][3][4]

Bolyerioidea Xenophidiidae Bolyeriidae Caenophidia †Anomalophiidae †Russellophiidae Acrochordoidea †Nigerophiidae Acrochordidae †Palaeophiidae †Archaeophinae †Palaeophiinae Colubroides Xenodermidae Colubriformes Pareidae Pareinae Xylophiinae Viperidae Viperinae Azemiopinae Crotalinae Endoglyptodonta Homalopsidae Elapoidea Prosymnidae Buhoma Psammophiidae Pseudaspidinae Psammophiinae Lamprophiidae Pseudoxyrhophiinae Micrelapiinae Psammodynastiinae Lamprophiinae Elapidae Calliophiinae Micrurinae Najinae Bungarinae Elapsoidea Hydrophiinae Atractaspididae Cyclocorinae Atractaspidinae Colubroidea Colubridae Grayiinae Calamariinae Ahaetuliinae Colubrinae Sibynophiidae Natricidae Pseudoxenodontidae Dipsadidae Carphophiinae Xenodontinae Dipsadinae

References

1. Vidal, Nicolas; Delmas, Anne-Sophie; David, Patrick; Cruaudd, Corinne; Couloux, Arnaud; Hedges, S. Blair (2007). "The phylogeny and classification of caenophidian snakes inferred from seven nuclear protein-coding genes". Comptes Rendus Biologies. 330 (2): 182–187. doi:10.1016/j.crvi.2006.10.001. PMID 17303545.
2. Rieppel, O. (1979). "A cladistics classification of primitive snakes based on skull structure". Journal of Zoological Systematics and Evolutionary Research. 17 (2): 140–150. doi:10.1111/j.1439-0469.1979.tb00696.x.
3. Reynolds, RG; Niemiller, ML; Revell, LJ (2014). "Toward a Tree-of-Life for the boas and pythons: multilocus species-level phylogeny with unprecedented taxon sampling" (PDF). Molecular Phylogenetics and Evolution. 71: 201–213. doi:10.1016/j.ympev.2013.11.011. PMID 24315866. Archived from the original (PDF) on 2015-12-02. Retrieved 2019-03-04.
4. Figueroa, A.; McKelvy, A. D.; Grismer, L. L.; Bell, C. D.; Lailvaux, S. P. (2016). "A species-level phylogeny of extant snakes with description of a new colubrid subfamily and genus". PLOS ONE. 11 (9): e0161070. Bibcode:2016PLoSO..1161070F. doi:10.1371/journal.pone.0161070. PMC 5014348. PMID 27603205.
5. Pyron; Burbrink; Wiens (2013). "A phylogeny and revised classification of Squamata, including 4161 species of lizards and snakes". BMC Evolutionary Biology. 13: 93. doi:10.1186/1471-2148-13-93. PMC 3682911. PMID 23627680.