Canthus (herpetology)

Last updated

In snakes and amphibians, the canthus, canthal ridge or canthus rostralis, [1] is the angle between the flat crown of the head and the side of the head between the eye and the snout, [2] 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. [3] [4]

Related Research Articles

<span class="mw-page-title-main">Keeled scales</span> Reptile scales with ridges

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.

<span class="mw-page-title-main">Gaboon viper</span> Species of snake

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.

<i>Bothrops</i> Genus of snakes

Bothrops is a genus of highly venomous pit vipers endemic to the Neotropics. The generic name, Bothrops, is derived from the Greek words βόθρος, bothros, meaning "pit", and ώπς, ops, meaning "eye" or "face", together an allusion to the heat-sensitive loreal pit organs. Members of this genus are responsible for more human deaths in the Americas than any other group of venomous snakes. Currently, 48 species are recognized.

<span class="mw-page-title-main">Russell's viper</span> Species of venomous snake

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.

<i>Bitis</i> Genus of snakes

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.

<i>Hypnale</i> Genus of snakes

Hypnale is a genus of venomous pit vipers endemic to Sri Lanka and southwestern India. Three monotypic species are currently recognized. All members have more or less upturned snouts that produce a hump-nosed effect.

<i>Atheris</i> Genus of venomous vipers of tropical Africa

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.

<i>Cerastes</i> (genus) Genus of snakes

Cerastes is a genus of small, venomous vipers found in the deserts and semi-deserts of northern North Africa eastward through Arabia and Iran. Three species are currently recognized by ITIS, and an additional recently described species is recognized by the Reptile Database. Common names for members the genus include horned vipers, North African desert vipers, and cerastes vipers.

<i>Echis</i> Genus of snakes

Echis is a genus of vipers found in the dry regions of Africa, the Middle East, India, Sri Lanka and Pakistan. They have a characteristic threat display, rubbing sections of their body together to produce a "sizzling" warning sound. The name Echis is the Latin transliteration of the Greek word for "viper" (ἔχις). Like all vipers, they are venomous. Their common name is "saw-scaled vipers" and they include some of the species responsible for causing the most snakebite cases and deaths in the world. Twelve species are currently recognized.

<i>Azemiops</i> Genus of snakes

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.

<i>Vipera ammodytes</i> Species of snake

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.

<i>Vipera aspis</i> Species of snake

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.

<i>Bitis parviocula</i> Species of snake

Bitis parviocula is a venomous viper species found only in Ethiopia. It is large with a broad head and spectacular geometric markings. In 1995, the species was known from only three specimens, but additional information has surfaced since then. Little is known about its natural history or its venom. 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.

<span class="mw-page-title-main">Snake scale</span> Scales covering the skin of snakes

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.

<i>Vipera darevskii</i> Species of snake

Vipera darevskii, known as Darevsky's viper, is a small species of viper, a venomous snake in the subfamily Viperinae of the family Viperidae. The species is native to northwestern Armenia, northeastern Turkey, and possibly also adjacent southern Georgia. There are no subspecies that are recognized as being valid.

<span class="mw-page-title-main">Persian horned viper</span> Species of snake

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.

<i>Metlapilcoatlus nummifer</i> Species of snake

Metlapilcoatlus nummifer, commonly known as Mexican jumping pitviper or jumping viper, is a venomous pit viper species endemic to Mexico.

In snakes, the canthals are the scales along the upper surface of the canthus rostralis. They are located behind the level of the prenasal/postnasal suture and before the supraocular. They are also described as being located along the edge of the crown between the internasals and the supraoculars. If these are large scales that contact each other along the midline, they are more properly referred to as prefrontals.

References

  1. Spawls S, Branch B. 1995. The Dangerous Snakes of Africa. Ralph Curtis Books. Dubai: Oriental Press. 192 pp. ISBN   0-88359-029-8.
  2. Mallow D, Ludwig D, Nilson G. 2003. True Vipers: Natural History and Toxinology of Old World Vipers. Krieger Publishing Company, Malabar, Florida. ISBN   0-89464-877-2.
  3. Campbell JA, Lamar WW. 2004. The Venomous Reptiles of the Western Hemisphere. Comstock Publishing Associates, Ithaca and London. 870 pp. 1500 plates. ISBN   0-8014-4141-2.
  4. Wareham, David C. 2005. Dictionary of herpetological and related terminology. Elsevier. ISBN   0-444-51863-0