Skull differences in various species

With a few notes on dentition

Snakes can be classified into 4 major groups, depending on their dentition.

These groups are:

Aglyphs

The word "glyph" is derived from the the Greek word "gluphe" which means a carved or grooved channel. Thus the word "Aglyph" means "without a grooved channel". These snakes have no fangs with the characteristic groove necessary to transport venom. In general the more evolved a snake is the more the grooved channel is closed along its length to form a tube rather than a groove. The Aglyphous snakes include all non-colubroid snakes and many colubrids. In some cases the colubrids have actually lost their venom apparatus and fangs.

Skull of a Python

The python is well equipped with numerous large recurved teeth designed to assist it to grip its prey during constriction. The quadrate bone is short and massive and the mandible is relatively small. This type of skull is typically Aglyphous. There are no fangs and no poison apparatus.

Skull of a Mole Snake

Perhaps a better example of an Aglyph's skull is that of the Mole Snake. No venom apparatus and no fangs are to be seen. However these small teeth can be quite viciously employed and mole snake bites can be extremely painful. Loss of fingers has been recorded as a consequence of a mole snake bite.

A Green Tree python demonstrating its aglyphous teeth. It has no fangs.

Opistoglyphs - Ophistoglyphs

Opisto - derived from the Greek "Ophisto" meaning "behind". The opisto- or ophistoglyphs represent that group of snakes known as the "rear-fanged" group. This type of dentition is often encountered in colubrids. Our best examples are the Boomslang and the Vine snake - the bite of both can be fatal to humans.

Skull of a Boomslang

The Boomslang skull displays is rear-fangs. This type of skull is a fine example of an Opistoglyph.

An Opistoglyphous sandsnake shows it small rear fangs.

Proteroglyphs

From the Greek "proteros" meaning "former". These are the "front-fanged" snakes and includes most of the Elapids. The groove is now tending to be closed for the greater part of its length.

Skull of a Cobra

The Cobra skull displays its relatively short fangs. The mandible is fairly well set back with a short strong quadrate bone. This skull type is a fair example of the Proteroglyphs.

A Green Mamba shows its proteroglyphous front fangs.

Solenoglyphs

From the Greek "Soleno" meaning "pipe". Thus the solenoglyphs tend to have the most perfect of the venomous fangs, being entubed almost their entire length. The fang tends to be long, articulated and can be erected under the snake's control. It allows for deep injection of venom. It is characteristic of the vipers and adders. The Atractaspidae also have this form of fang.

Skull of a Puff Adder

The Puff Adder skull reveals a pair of large fangs. The quadrate bone is long and slender and the mandible stretches well to the back of the skull. This is a typical "viperine" skull and the type is a Solenoglyph. The fang is erectile and a well developed poison apparatus exists.

Fangs of a Puff Adder

The hollow or grooved nature of the fangs of the puff adder are clearly visible in this photograph.

Venom gland and fang of a Puff Adder

The well-developed venom apparatus and fang of a puff adder can be seen in the above photograph. The venom gland is in actual fact a modified salivary gland and is linked to the groove in the fangs by a duct.

A Desert Horned Viper gives evidence of its Solenoglypghous fangs.

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Copyright: Séan Thomas & Eugene Griessel - Dec 1999.