In snakes, the anal scale or anal plate is the scale just in front of and covering the cloacal opening. This scale can be either single ("anal entire") or paired ("anal divided"). When paired, the division is oblique. [1] [2] The anal scale is preceded by the ventral scales and followed by the subcaudal scales.
The Gaboon viper, also called the Gaboon adder, is a viper species found in the rainforests and savannas of sub-Saharan Africa. Like all other vipers, it is venomous. It is the largest member of the genus Bitis, and it has the longest fangs of any venomous snake – up to 2 inches (5 cm) in length – and the highest venom yield of any snake. No subspecies are recognized.
Russell's viper is a venomous snake in the family Viperidae native to the Indian subcontinent and one of the big four snakes in India. It was described in 1797 by George Shaw and Frederick Polydore Nodder, and named after Patrick Russell, who wrote about it in his 1796 work An account of Indian serpents, collected on the coast of Coromandel.
Bitis is a genus of venomous vipers found in Africa and the southern Arabian Peninsula. It includes the largest and the smallest vipers in the world. Members are known for their characteristic threat displays that involve inflating and deflating their bodies while hissing and puffing loudly. The type species for this genus is B. arietans, which is also the most widely distributed viper in Africa. Currently, 18 species are recognized.
Heterodon is a genus of harmless colubrid snakes endemic to North America. They are stout with upturned snouts and are perhaps best known for their characteristic threat displays. Three species are currently recognized. Members of the genus are commonly known as hognose snakes, hog-nosed snakes, North American hog-nosed snakes, and colloquially puff adders.
Causus is a genus of vipers found only in sub-Saharan Africa. It is a group considered to be among the most primitive members of the family Viperidae based on head scalation, oviparity, venom apparatus, and because they have round pupils. However, this is contradicted by recent molecular studies. Seven species are currently recognized. They are commonly known as night adders. Like all other vipers, they are venomous.
Azemiopinae is a monogeneric subfamily created for the genus Azemiops that contains the viper species A. feae and A. kharini. They are commonly known as Fea's vipers. No subspecies are recognized. The first specimen was collected by Italian explorer Leonardo Fea, and was described as a new genus and new species by Boulenger in 1888. Formerly considered to be one of the most primitive vipers, molecular studies have shown that it is the sister taxon to the pit vipers, Crotalinae. It is found in the mountains of Southeast Asia, in China, southeastern Tibet, and Vietnam. Like all other vipers, they are venomous.
Atheris barbouri is a small and rare species of terrestrial viper endemic to the Uzungwe and Ukinga mountains of south-central Tanzania in Africa.
Vipera ammodytes is a viper species found in southern Europe, mainly northern Italy, the Balkans, and parts of Asia Minor. Like all other vipers, it is venomous. It is reputed to be the most dangerous of the European vipers due to its large size, long fangs and high venom toxicity. The specific name, ammodytes, is derived from the Greek words ammos, meaning "sand", and dutes, meaning "burrower" or "diver", despite its preference for rocky habitats. Five subspecies are currently recognized, including the nominate subspecies described here.
Vipera aspis is a viper species found in southwestern Europe. Its common names include asp, asp viper, European asp, and aspic viper, among others. Like all other vipers, it is venomous. Bites from this species can be more severe than from the European adder, V. berus; not only can they be very painful, but approximately 4% of all untreated bites are fatal. The specific epithet, aspis, is a Greek word that means "viper." Five subspecies are currently recognized, including the nominate subspecies described here.
Atheris hispida is a viper species endemic to Central Africa. Like all other vipers, it is venomous. It is known for its extremely keeled dorsal scales that give it a bristly appearance. No subspecies are currently recognized. Common names include rough-scaled bush viper, spiny bush viper, hairy bush viper, and others.
Bitis peringueyi, also known as the Peringuey's adder, Peringuey's desert adder or desert sidewinding adder, is a venomous viper species found in Namibia and southern Angola. No subspecies are currently recognized.
Vipera transcaucasiana is a venomous viper species endemic to parts of Georgia and northern Turkish Anatolia.
Causus resimus is a viper species found in isolated populations distributed across tropical Africa. No subspecies are currently recognized. Like all other vipers, it is venomous.
In reptiles, the nasal scale refers to the scale that encloses the nostril.
The mental scale, or mental, in snakes and other scaled reptiles refers to the median plate on the tip of the lower jaw. It is a triangular scale that corresponds to the rostral of the upper jaw. The reference to the term 'mental' comes from the mental nerve which addresses the chin and lower jaw in animals. In snakes, the shape and size of this scale is sometimes one of the characteristics used to differentiate species from one another.
In scaled reptiles, the ocular scales are those forming the margin of the eye. The name originates from the term oculus which is Latin for 'eye' and, in the broadest sense, refers to a scale associated with the eye. The numbers of these scales present, and sometimes the shapes and sizes, are some of many characteristics used to differentiate species from one another.
In reptiles, the nasorostral is an enlarged and usually paired scale, just behind the rostral.
In snakes, the subcaudal scales are the enlarged plates on the underside of the tail. These scales may be either single or divided (paired) and are preceded by the anal scale.
In reptiles, occipital scales are enlarged plates that lie directly behind the parietal scales.
Agkistrodon contortrix mokasen was formerly a venomous pit viper subspecies found in the eastern United States. However, recent taxonomic changes do not recognize the northern copperhead as a valid taxon.