The Duvernoy's gland is a gland found in some groups of ''

colubrid Colubridae (, commonly known as colubrids , from , 'snake') is a family of snakes. With 249 genera, it is the largest snake family. The earliest fossil species of the family date back to the Late Eocene epoch, with earlier origins suspected. Colu ...

snake Snakes are elongated limbless reptiles of the suborder Serpentes (). Cladistically squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales much like other members of the group. Many species of snakes have s ...

s. It is distinguished from the venom gland and is not found in ''

viperids Vipers are snakes in the family Viperidae, found in most parts of the world, except for Antarctica, Australia, Hawaii, Madagascar, New Zealand, Ireland, and various other isolated islands. They are venomous snake, venomous and have long (relat ...

'' or ''

elapids Elapidae (, commonly known as elapids , from , variant of "sea-fish") is a family of snakes characterized by their permanently erect fangs at the front of the mouth. Most elapids are venomous, with the exception of the genus '' Emydocephalus' ...

''. It was named for

French French may refer to: * Something of, from, or related to France ** French language, which originated in France ** French people, a nation and ethnic group ** French cuisine, cooking traditions and practices Arts and media * The French (band), ...

zoologist Zoology ( , ) is the scientific study of animals. Its studies include the structure, embryology, classification, habits, and distribution of all animals, both living and extinct, and how they interact with their ecosystems. Zoology is one ...

Georges Louis Duvernoy Georges Louis Duvernoy (6 August 1777, Montbéliard, Doubs – 1 March 1855) was a French zoologist. He assisted Georges Cuvier in writing ''Leçons d'anatomie comparée''. He was elected a member of the French Academy of Sciences in 1847 and a fo ...

who first described the gland in 1832. The Duvernoy's gland is positioned posterior to the eye, encased in a thin cover of connective tissue, and consists mostly of serous cells. A single, short duct extends anteromedially from the lumen of the gland to the base of the posterior fangs.

Function

The function of the Duvernoy's gland has been the source of much study and speculation, and debate is still ongoing. It is widely recognized that the Duvernoy's gland is the homologue of

venom Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a sti ...

glands in vipers and elapids. However, the two types of glands are also “anatomically and functionally distinct,” leading experts such as Dr. Kenneth Kardong to maintain the distinction between the Duvernoy's gland and venom glands. Other scientists such as Dr. Bryan Fry maintain that the Duvernoy gland is a primitive version of a venom gland and should be referred to as such. Dr. Stephen Mackessy suggests Duvernoy's gland does secrete venom and is homologous to the venom gland found in front-fanged snakes. Because the secretions of this gland are associated with the swallowing behavior of snakes, the Duvernoy's gland may play a role in swallowing and/or digestion. Kardong also notes that although some Duvernoy's gland secretions may be toxic and that they can produce pain, swelling, and other effects if injected subcutaneously; this does not make those secretions venoms.The word "

toxic Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a subst ...

" describes the properties of the substance whereas the word "

" implies its biological use for the organism.

Evolution

The evolutionary path of these separate glands may come from “venom proteins” whose genes are widely expressed in tissues of both venomous and non-venomous snakes. These genes are over-expressed in the venom glands (including Duvernoy's gland), indicating the secretions from these glands evolved separately, rather than sequentially.

References

{{reflist Glands Snake anatomy