Snakes - Herp Study

Number of Snakes

4023 species

Number of Vertebrae

120-240 vertebrae

Quadrate

highly movable bone allowing for skull kenisis

Coniophis and Lapparentophis

oldest snake fossils - Early Cretaceous, 121–127 mya.

Najash

fossil snake with small but distinct hindlimbs from the Cretaceous, ~95mya

Macrostomy

a large mouth and gape due to a movable quadrate bone.

° Kinetic skull with streptostyly and pterygoid–palatine mobility.

° Elongate supratemporal bone.

° Free posterior end of the maxilla.

° Mandibular rami connected by an elastic ligament.

macrostomatan condition was primitive for living snakes and that the "small-mouth" condition in Scolecophidia, Uropeltidae, Aniliidae, etc. is associated with return to a burrowing existence

Scolecophidia

Blind snakes

Typhlopidae + Gerrhopilidae +Xenotyphlopidae

Anomalepididae

Leptotyphlopidae

Alethinophidia

° Tropidophiidae (dward boa)  + Aniliidae (pipe snake, false coral) 

° "Booids" - boas

° Caenophidia - 80% of all the extant species of snakes. The largest family is Colubridae

Colubroidea

(Family Name) Xenodermatidae, Pareatidae, Elapidae, Viperidae, Homalopsidae, Colubridae, Lamprophiidae.

Uropeltidae

shield tailed snakes

Rhinophis blythii

Pythonidae

40 species, Many have infrared (heat) receptors in interlabial pits

P. molurus has true egg brooding, using an elevated body temperature. • Most have cloacal spurs.

Boidae

true _____. • 67 species.All viviparous. • Variety of forms: arboreal, terrestrial, aquatic, semifossorial.

Boinae

Only the subfamily ____ (among Boidae) have infrared sensory pits.

Boas

Epicrates. Rainbow Boas, South America.

° Eunectes. South America, Anaconda. Perhaps up to 7-8m. 150kg (330lbs).

° Corallus. South America, Tree boas.

° Boa. Mexico, Central, and South America, Boa constrictor.

° Lichanura trivirgata. US, Rosy Boa.

° Eryx. Europe, Asia, Sand boas.

Acrochordidae

file snakes

Baggy, distinctly granular skin. • Strongly aquatic, including coastal marine environments

Colubroidea

Advanced snakes

colubroids

________ family has fangs and venom

Solenoglyph

________ fangs are long, tubular and fixed to a small rotatable maxilla. Found in Viperidae. These are dangerous to humans

Proteroglyph

________ fangs are attached to a maxilla that does not rotate. Found in Elapidae. These are very dangerous to humans.

Opisthoglyph

_______fangs ("rear-fanged") are elongate and grooved (usually more than one) at the rear of a maxilla of “normal” length. These fangs are found in many unrelated groups of colubroids.

Aplopeltura boa, Dipsas indica

Snail-Eaters

Viperidae

some have pits

All are venomous (solenoglyphs)

There is a single fang on a very short maxillary bone, which rotates forward to direct the fang anteriorly.

Colubridae

2560 species (7 subfamilies). This includes more t half of all snake species. • All continents, but with smaller representation in Australia. • Extremely diverse in ecomorphology and habitats. • Many, but not all, _____ are opisthoglyphs.

Elapidae

• 391 species.

• Ecological very diverse.

• Coral snakes, cobras, kraits, mambas, adders, sea snakes.

• Most of all australian snakes

Proteroglyph Fangs