In reptiles, the nasal scale refers to the scale that encloses the nostril. [1]
Sometimes this scale is paired (divided). In such cases, the anterior half is referred to as the prenasal and the posterior half is referred to as the postnasal. [2]
Supranasal scales are located above the nasal scale. [1]
Viperinae, or viperines, are a subfamily of vipers endemic to Europe, Asia and Africa. They are distinguished by their lack of the heat-sensing pit organs that characterize their sister group, the subfamily Crotalinae. Currently, 13 genera are recognized. Most are tropical and subtropical, although one species, Vipera berus, even occurs within the Arctic Circle. Like all vipers, they are venomous.
Keeled scales refer to reptile scales that, rather than being smooth, have a ridge down the center that may or may not extend to the tip of the scale, making them rough to the touch. According to Street's (1979) description of European lizards and snakes, in those that have keeled scales the keels are usually stronger in male specimens and are consistently arranged according to the species of reptiles, even though many others do not have them. With European lizards, the dorsal scales are usually well keeled, while those on the flanks are more weakly keeled and those on the belly smooth. Non-European lizards such as Sphaerodactylus macrolepis also display keeled scales.
Russell's viper is a highly 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.
Macrovipera lebetinus, known as the blunt-nosed viper, Lebetine viper, Levant viper, and by other common names, is a viper species found in North Africa, much of the Middle East, and as far east as Kashmir. Like all other vipers, it is venomous. Five subspecies are currently recognized, including the nominate race described here.
Atheris is a genus of vipers known as bush vipers. They are found only in tropical subsaharan Africa and many species have isolated and fragmented distributions due to their confinement to rain forests. Like all other vipers, they are venomous. In an example of convergent evolution, they show many similarities to the arboreal pit vipers of Asia and South America. Seventeen species are currently recognized.
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.
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.
In snakes and amphibians, the canthus, canthal ridge or canthus rostralis, is the angle between the flat crown of the head and the side of the head between the eye and the snout, or more specifically, between the supraocular scale and the rostral scale. It is defined as a sharp ridge in many viperids, but is rounded in most rattlesnakes, for example.
Bitis rhinoceros is a viper species endemic to West Africa. Like all vipers, it is venomous. It can be easily distinguished from the closely related species B. gabonica by the presence of two large nasal "horns".
Montivipera raddei albicornuta is a venomous viper subspecies endemic to Iran. It is a subspecies of Montivipera raddei.
Vipera transcaucasiana is a venomous viper species endemic to parts of Georgia and northern Turkish Anatolia.
Snakes, like other reptiles, have skin covered in scales. Snakes are entirely covered with scales or scutes of various shapes and sizes, known as snakeskin as a whole. A scale protects the body of the snake, aids it in locomotion, allows moisture to be retained within, alters the surface characteristics such as roughness to aid in camouflage, and in some cases even aids in prey capture. The simple or complex colouration patterns are a property of the underlying skin, but the folded nature of scaled skin allows bright skin to be concealed between scales then revealed in order to startle predators.
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 snakes, the internasal scales are those on top of the head between the scales that surround the nostrils. They are usually paired and situated just behind the rostral.
In reptiles, the nasorostral is an enlarged and usually paired scale, just behind the rostral.
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 or paired. When paired, the division is oblique. The anal scale is preceded by the ventral scales and followed by the subcaudal scales.
In reptiles, occipital scales are enlarged plates that lie directly behind the parietal scales.
The Persian horned viper, known as the Persian horned viper, false horned viper, and by other common names, is a species of vipers endemic to the Middle East and Asia. Like all other vipers, it is venomous.