Palaeos		Squamata
The Vertebrates		Pythonomorpha: Colubroidea

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Squamata: Pythonomorpha: Colubroidea

Abbreviated Dendrogram

SQUAMATA
|--Iguania
Scleroglossa
|
Pythonomorpha
|--Mosasauroidea 
`--Serpentes
   |--Scolecophidia
   `--Alethinophidia
      |--Aniloidea
      `--Macrostomata
         |--Boidae
         `--Caenophidia
            |--Acrochordoidea
            `--Colubroidea
               |--Atractaspididae 
               |--Elapidae
               `--+--Colubridae
                  `--Viperidae
                     |--Azemiopinae 
                     `--+--Crotalinae 
                        `--Viperinae

Contents

Overview
Squamata
Iguania
Acrodonta
Scincogekkonomorpha
Scleroglossa
Scincomorpha
Anguimorpha
Pythonomorpha
Mosasauridae
Scolecophidia
Alethinophidia
Macrostomata
Colubroidea
Dendrogram
References

Descriptions

Colubroidea: Earliest advanced snakes.

Range: fr Ec.

Phylogeny: Caenophidia: Acrochordoidea + *: Atractaspididae + Elapidae + (Colubridae + Viperidae).

Links: Higher Reptile Taxa.

Atractaspididae:

Range: currently Africa & Asia

Phylogeny: Colubroidea: Elapidae + (Colubridae + Viperidae) + *.

Characters: small to medium-sized snakes; blunt-headed; maxilla is extremely reduced; maxilla with elongated, hollow maxillary fang; maxilla has complex articulation with prefrontal; short tails; fossorial; solenoglyphs; oviparous with clutches of 2-11; feed upon newborn rodents and other fossorial reptiles

Links: Atractaspididae; Atractaspididae

Elapidae:

Phylogeny: Colubroidea: Atractaspididae + (Colubridae + Viperidae) + *.

Characters: Venomous, often marine snakes with hollow, relatively immobile maxillary fangs.

Boiga dendrophila, the mangrove snake. From the Virtual Museum of Natural History, by permission.

Colubridae:rat snakes, corn snakes, king snakes, garter snakes, indigo snakes, boomslangs, etc.

Range: All continents except Antarctica (and Australia?), in all but coldest latitudes.

Phylogeny: Colubroidea:: Viperidae + *.

Characters: 20-400 cm; frequently venomous but without anterior fangs or hollow teeth; venom, where present, mostly proteases; most have rows of teeth that are of equal size; teeth on premaxillae lost; maxilla elongate; basipterygoid processes lost; coronoids lost; pupils round; vertebrae generally lack downward-projecting spines; right common artery lost; pelvic girdle absent; large, strap-like scales in single row down the belly; most terrestrial.

Note: Very speciose taxon, with 85-90% of living species. May be a catch-all taxon for advanced snakes of multiple lineages. ATW021012.

Links: Family Colubridae; Flying snake home page (Colubridae: Chrysopelea); Reptilia, Squamata, Ophidia, Colubridae, Nattern (German); Colubridae, (Italian); Predacao de anuros pela serpente (Portugese); ????????? ?????? (Colubridae). ????: Colubrids. (Russian); Colubridae; I Colubridi, Colubridae (Italian); APUS.RU - Colubridae (Russian); SERPENTS (also in Russian); Advanced Snakes (pictures & lots of references); Colubridae.html (pictures). ATW030128.

Viperidae: adders, vipers, & copperheads.

Range: from the Early Miocene.

Phylogeny: Colubroidea:: Colubridae + *: Azemiopinae + (Crotalinae + Viperinae).

Characters: Large, triangular heads & stout bodies; maxilla short, with one tooth; maxillae rotates so that fangs folded during feeding (distinguishes from Elapids); venom teeth are closed tubes (solenoglyph) without visible seam; quadrates flared outward and highly mobile skull; venom common. Largely ambush predators of mammals, injecting venom, then following scent trail.

Image:Agkistrodon contortrix laticinctus from Viperidae.

Links: Encyclopedia Entry; Viperidae; Family- Viperidae (ADW); Reptilia, Squamata, Ophidia, Viperidae - Vipern (German); Viperidae.html (just pictures); Viperidae Familyasi (Turkish); I Viperidi, Viperidae (Italian: very thorough coverage); Viperidae (Mikko). ATW030121.

Azemiopinae: (= Azemophinae): Azemiops (Fea's viper).

Range: R of China, Tibet, northern parts of SE Asia.

Phylogeny: Viperidae: (Crotalinae + Viperinae) + *.

Characters: <82 cm long; head somewhat flattened & slightly triangular; fangs short; venom sacs comparatively small; loreal (infra-red sensitive) pit-organs absent; moderately sturdy body, with short tail; no tracheal lung; head with with large plates (colubridlike head scales); head scales orange; smooth body scales, body has widely spaced orange rings on a background of deep blue-gray to black; feeds on small mammals and lizards; vibrates tail against vegetation when threatened; hibernates in winter; oviparous.

Image:Azemiops from Viperidae.

Links: Viperidae; NCBI; ??? - ???? Azemiops feae (Chinese). ATW030503.

Crotalinae:

Phylogeny: Viperidae:: Viperinae + *.

Viperinae: Adenorhinos, Atheris, Bitis, Cerastes, Daboia, Echis, Macrovipera, Vipera. "Pitless vipers."

Phylogeny: Viperidae:: Crotalinae + *.

Links:Viperinae; Viperidae; Viperinae2001; The World Of Atheris; Biochem. J. - Bile acids of Viperinae; Viper's; Snake Basics 2 - Simon's Snake Website. ATW020817.

checked ATW060222