The mental scale, or mental, in snakes and other scaled reptiles refers to the median plate on the tip of the lower jaw. [1] It is a triangular scale that corresponds to the rostral of the upper jaw. [2] 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.
Atheris squamigera is a venomous viper species endemic to west and central Africa. No subspecies are currently 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.
Vipera ammodytes, commonly known as horned viper, long-nosed viper, nose-horned viper, and sand viper, is a species of viper 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.
The Florida cottonmouth is a species of venomous snake, a pit viper in the subfamily Crotalinae of the family Viperidae. The species is endemic to the United States, where it occurs in southern Georgia and the Florida peninsula in nearly every type of wetlands in the region, including brackish water and offshore islands. However, it is not entirely dependent on water and is occasionally encountered as far as a mile from surface water. Agkistrodon conanti venom is very hemolytic and known to cause relatively extensive necrosis compared to many snake venoms, and can sometimes be lethal with a 17% mortality rate. It is often confused with harmless watersnakes (Nerodia) and other semi-aquatic species with which it shares its habitat.
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.
Atheris ceratophora is a venomous viper species endemic to a few mountain ranges in Tanzania. This used to be the only horned, arboreal viper known from Africa, until the discovery in 2011 of Atheris matildae, also found in Tanzania. No subspecies are currently recognized.
Vipera ammodytes meridionalis is a venomous viper subspecies endemic to Greece and Turkish Thrace.
Vipera ammodytes montandoni is a venomous viper subspecies endemic to Bulgaria and southern Romania.
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 labial scales are the scales of snakes and other scaled reptiles that border the mouth opening. These do not include the median scales on the upper and lower jaws. The term labial originates from Labium, which refers to any lip-like structure. In snakes, there are two different types of labial scales: supralabials and sublabials. 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 nasal scale refers to the scale that encloses the nostril.
The rostral scale, or rostral, in snakes and other scaled reptiles is the median plate on the tip of the snout that borders the mouth opening. It corresponds to the mental scale in the lower jaw. The term pertains to the rostrum, or nose. In snakes, the shape and size of this scale is one of many 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 supralabial scales, also called upper-labials, are those scales that border the mouth opening along the upper jaw. They do not include the median scale. The term labial originates from Labium, which refers to any lip-like structure. 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 sublabial scales, also called lower-labials or infralabials, are those scales that border the mouth opening along the lower jaw. They do not include the median scale. The term labial originates from labium, which refers to any lip-like structure. 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.