Anacondas or water boas are a group of large boas of the genus Eunectes. They are a semiaquatic group of snakes found in tropical South America. Three to five extant and one extinct species are currently recognized, including one of the largest snakes in the world, E. murinus, the green anaconda.
Snakes are elongated, limbless reptiles of the suborder Serpentes. Like all other squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales. Many species of snakes have skulls with several more joints than their lizard ancestors, enabling them to swallow prey much larger than their heads. To accommodate their narrow bodies, snakes' paired organs appear one in front of the other instead of side by side, and most have only one functional lung. Some species retain a pelvic girdle with a pair of vestigial claws on either side of the cloaca. Lizards have independently evolved elongate bodies without limbs or with greatly reduced limbs at least twenty-five times via convergent evolution, leading to many lineages of legless lizards. These resemble snakes, but several common groups of legless lizards have eyelids and external ears, which snakes lack, although this rule is not universal.
The Boidae, commonly known as boas or boids, are a family of nonvenomous snakes primarily found in the Americas, as well as Africa, Europe, Asia, and some Pacific islands. Boas include some of the world's largest snakes, with the green anaconda of South America being the heaviest and second-longest snake known; in general, adults are medium to large in size, with females usually larger than the males. Six subfamilies comprising 15 genera and 54 species are currently recognized.
The ball python, also called the royal python, is a python species native to West and Central Africa, where it lives in grasslands, shrublands and open forests. This nonvenomous constrictor is the smallest of the African pythons, growing to a maximum length of 182 cm (72 in). The name "ball python" refers to its tendency to curl into a ball when stressed or frightened.
Ophidia is a group of squamate reptiles including modern snakes and reptiles more closely related to snakes than to other living groups of lizards.
Loxocemus bicolor, the sole member of the monotypic family Loxocemidae and commonly known as the Mexican python, Mexican burrowing python and Mexican burrowing snake, is a species of python-like snake found in Mexico and Central America. No subspecies are currently recognized. Analyses of DNA show that Loxocemus is most closely related to the true pythons and the sunbeam snakes.
Henophidia is a former superfamily of the suborder Serpentes (snakes) that contains boas, pythons and numerous other less-well-known snakes.
The green anaconda, also known as the giant anaconda, emerald anaconda, common anaconda, common water boa, or southern green anaconda, is a semi-aquatic boa species found in South America and the Caribbean island of Trinidad. It is the largest, heaviest, and second longest snake in the world, after the reticulated python. No subspecies are currently recognized. Like all boas, it is a non-venomous constrictor. The term "anaconda" often refers to this species, though the term could also apply to other members of the genus Eunectes. Fossils of the snake date back to the Late Pleistocene in the Gruta do Urso locality.
The Indian python is a large python species native to tropical and subtropical regions of the Indian subcontinent and Southeast Asia. It is also known by the common names black-tailed python, Indian rock python, and Asian rock python. Although smaller than its close relative the Burmese python, it is still among the largest snakes in the world. It is generally lighter colored than the Burmese python and reaches usually 3 m. Like all pythons, it is nonvenomous.
A hemipenis is one of a pair of intromittent organs of male squamates. Hemipenes are usually held inverted within the body, and are everted for reproduction via erectile tissue, much like that in the human penis. They come in a variety of shapes, depending on species, with ornamentation such as spikes.
The blue-lipped sea krait, also known as the blue-banded sea krait or common sea krait, is a species of venomous sea snake in the subfamily Laticaudinae of the family Elapidae. It is found in the Indian and Western Pacific Oceans.
Pachyrhachis is an extinct genus of snake with well developed hind legs known from fossils discovered in Ein Yabrud, near Ramallah, in the central West Bank. It is a relatively small snake, measuring more than 1.5 metres (4.9 ft) long at maximum. Pachyrhachis appears to have been an ancient marine snake; the fossils occur in a marine limestone deposit, and the thickened bone of the ribs and vertebrae would have functioned as ballast to decrease the buoyancy of the animal, allowing it to dive beneath the ancient Cretaceous seas that it once inhabited.
Python is a genus of constricting snakes in the Pythonidae family native to the tropics and subtropics of the Eastern Hemisphere.
Madtsoiidae is an extinct family of mostly Gondwanan snakes with a fossil record extending from early Cenomanian to late Pleistocene strata located in South America, Africa, India, Australia and Southern Europe. Madtsoiidae include very primitive snakes, which like extant boas and pythons would likely dispatch their prey by constriction. Genera include some of the longest snakes known such as Vasuki, measuring at least 11–15 metres (36–49 ft) long, and the Australian Wonambi and Yurlunggur. As a grouping of basal forms the composition and even the validity of Madtsoiidae is in a state of flux as new pertinent finds are described, with more recent evidence suggesting that it is paraphyletic as previously defined.
The Alethinophidia are an infraorder of snakes that includes all snakes other than blind snakes and thread snakes. Snakes have long been grouped into families within Alethinophidia based on their morphology, especially that of their teeth. More modern phylogenetic hypotheses using genetic data support the recognition of 19 extant families, although the taxonomy of alethinophidian snakes has long been debated, and ultimately the decision whether to assign a particular clade to a particular Linnaean rank is arbitrary.
Eupodophis is an extinct genus of snake from the Late Cretaceous period. It has two small hind legs and is considered a transitional form between Cretaceous lizards and limbless snakes. The feature, described as vestigial, was most likely useless to Eupodophis. The type species Eupodophis descouensi was named in 2000 and resides now in the paleontology section of the Mim Museum in Beirut, Lebanon. The specific name is dedicated to the French naturalist Didier Descouens.
The boa constrictor, also known as the common boa, is a species of large, non-venomous, heavy-bodied snake that is frequently kept and bred in captivity. The boa constrictor is a member of the family Boidae. The species is native to tropical South America. A staple of private collections and public displays, its color pattern is highly variable yet distinctive. Four subspecies are recognized.
A spur is an outgrowth of bone covered in a sheath of horn found in various anatomical locations in some animals. Unlike claws or nails, which grow from the tip of the toes, spurs form from other parts of the foot, usually in connection with joints where the toes meet the foot or the foot meets the long bones. Spurs are most commonly found on the hindfeet, though some birds possess spurs at the leading edge of the wings.
Malayopython is a genus of constricting snakes in the family Pythonidae. The genus is native to India and Southeast Asia. It contains two species, both of which were previously classified within the genus Python. However, multiple studies recovered these species as distinct. Known as the "reticulatus clade", it was eventually found to be a sister lineage to a lineage giving rise to the Indo-Australian pythons rather than the genus Python.
The Amerophidia, also known as amerophidian snakes, are a clade of snakes that contains two families: Aniliidae and the boa-like Tropidophiidae.
