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Alethinophidia
:''Common names: advanced snakes.'' 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 (see below), 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 (such as a superfamily, family, or subfamily) is arbitrary. Etymology The infraorder name Alethinophidia derives from the two Ancient Greek words (), meaning "truthful, genuine", and (), meaning "snake". Fossil record Fossils of alethinophidians were found in Cenomanian (Middle Cretaceous) sites of Wadi Milk Formation in Wadi Abu Hashim, Sudan. '' Coniophis'' presents the vertebral morphology similar to modern-day Aniliidae. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snakes
Snakes are elongated Limbless vertebrate, limbless reptiles of the suborder Serpentes (). Cladistically Squamata, squamates, snakes are ectothermic, amniote vertebrates covered in overlapping Scale (zoology), scales much like other members of the group. Many species of snakes have skulls with several more joints than their lizard ancestors and relatives, enabling them to swallow prey much larger than their heads (cranial kinesis). To accommodate their narrow bodies, snakes' paired organs (such as kidneys) appear one in front of the other instead of side by side, and most only have 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amerophidia
The Amerophidia, also known as amerophidian snakes, are a clade of snakes that contains two families: Aniliidae (containing a single species, '' Anilius scytale'', the American red pipe snake or false coral snake) and the boa-like Tropidophiidae (containing two genera, '' Trachyboa'' (with two species) and ''Tropidophis'' (with either 17 or 33, depending on the authority)). The sister-group relationship between these two families is surprising and unintuitive when only morphology is considered, because Aniliidae more closely resemble the Asian pipe snakes in the families Cylindrophiidae and Anomochilidae, whereas Tropidophiidae more closely resemble constricting, macrostomatan snakes such as Boidae and Pythonidae. However, every major phylogenetic analysis since 2007 has found support for the idea that these two families are one another's closest relatives, despite having last shared a common ancestor about 91 MYA I: 77-104 The oldest fossil member of this family is the extinct ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Afrophidia
Afrophidia is a clade of alethinophidian snakes comprising the groups Henophidia and Caenophidia, essentially making up the snakes people commonly associate with. The name refers to the deep split between Afrophidia and their sister taxon, Amerophidia, which originated in South American origin, and the afrophidians was recently hypothesized to represent a vicariant event of the breakup of Gondwanan South America and Africa. Unlike the scolecophidians and amerophidians, which have evolved to be small, the afrophidians have evolved many larger species. This is also the group in which venom Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a sti ... has been developed in several lines of snakes. Below is a phylogeny of Afrophidia recovered from numerous phylogenetic work on snakes: Venomo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
