| Heloderma texana Temporal range: | |
|---|---|
 | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | Squamata |
| Family: | Helodermatidae |
| Genus: | Heloderma |
| Species: | †H. texana |
| Binomial name | |
| †Heloderma texana Stevens, 1977 [1] | |
Heloderma texana is an extinct species of heloderm lizard known from Miocene sediments in Big Bend National Park. [2] It is the oldest fossil record of the genus Heloderma in North America. [3]
Reptiles, as most commonly defined, are the animals in the class Reptilia, a paraphyletic grouping comprising all sauropsids except birds. Living reptiles comprise turtles, crocodilians, squamates and rhynchocephalians (tuatara). As of March 2022, the Reptile Database includes about 11,700 species. In the traditional Linnaean classification system, birds are considered a separate class to reptiles. However, crocodilians are more closely related to birds than they are to other living reptiles, and so modern cladistic classification systems include birds within Reptilia, redefining the term as a clade. Other cladistic definitions abandon the term reptile altogether in favor of the clade Sauropsida, which refers to all amniotes more closely related to modern reptiles than to mammals. The study of the traditional reptile orders, customarily in combination with the study of modern amphibians, is called herpetology.
Probainognathus meaning “progressive jaw” is an extinct genus of cynodonts that lived around 235 to 221.5 million years ago, during the Late Triassic in what is now Argentina. Together with the genus Bonacynodon from Brazil, Probainognathus forms the family Probainognathidae. Probainognathus was a relatively small, carnivorous or insectivorous cynodont. Like all cynodonts, it was a relative of mammals, and it possessed several mammal-like features. Like some other cynodonts, Probainognathus had a double jaw joint, which not only included the quadrate and articular bones like in more basal synapsids, but also the squamosal and surangular bones. A joint between the dentary and squamosal bones, as seen in modern mammals, was however absent in Probainognathus.
Anguidae refers to a large and diverse family of lizards native to the Northern Hemisphere. Common characteristics of this group include a reduced supratemporal arch, striations on the medial faces of tooth crowns, osteoderms, and a lateral fold in the skin of most taxa. The group is divided into two living subfamilies, the legless Anguinae, which contains slow worms and glass lizards, among others, found across the Northern Hemisphere, and Gerrhonotinae, which contains the alligator lizards, native to the Americas. The family Diploglossidae was also fomerly included. The family contains about 87 species in 8 genera.
The Helodermatidae or beaded lizards are a small family of lizards endemic to North America today, but formerly more widespread in the ancient past. Traditionally, the Gila monster and the Mexican beaded lizard were the only species recognized, although the latter has recently been split into several species.
Skinks are lizards belonging to the family Scincidae, a family in the infraorder Scincomorpha. With more than 1,500 described species across 100 different taxonomic genera, the family Scincidae is one of the most diverse families of lizards. Skinks are characterized by their smaller legs in comparison to typical lizards and are found in different habitats except arctic and subarctic regions.
Heloderma is a genus of toxicoferan lizards that contains five species, all of which are venomous. It is the only extant genus of the family Helodermatidae.
The Mexican beaded lizard is a species of lizard in the family Helodermatidae, one of the two species of venomous beaded lizards found principally in Mexico and southern Guatemala. It and the other members of the same genus, including the Gila monster, are the only lizards known to have evolved an overt venom delivery system. The Mexican beaded lizard is larger than the Gila monster, with duller coloration, black with yellowish bands. As it is a specialized predator that feeds primarily upon eggs, the primary use of its venom is still a source of debate among scientists. This venom has been found to contain several enzymes useful for manufacturing drugs in the treatment of diabetes, and research on the pharmacological use of its venom is ongoing.
Tremacebus is an extinct genus of New World monkeys from the Early Miocene. The type species is T. harringtoni.
Kaganaias is an extinct genus of basal and oldest dolichosaur that lived in what is now Japan during the Early Cretaceous. Kaganaias was semi-aquatic and is the only known aquatic squamate known from before the Cenomanian stage of the Cretaceous. It is also the first to be found in an inland area, instead of on the coast where aquatic squamates are commonly found. Its generic name is derived from Kaga Province, the old name for the Ishikawa Prefecture where the specimens were found, while the species name hakusanensis comes from the mountain that gives its name to Hakusan the city near its find site. The geological formation in which the specimens were found, the Kuwajima Formation, stands alongside the Tetori River and has been the site of numerous other finds including molluscs, dinosaurs, fish, and pterosaurs.
Estesia is an extinct genus of Late Cretaceous anguimorph lizard found in the Gobi Desert in Mongolia.
The Anguimorpha is a suborder of squamates. The group was named by Fürbringer in 1900 to include all autarchoglossans closer to Varanus and Anguis than Scincus. These lizards, along with iguanians and snakes, constitute the proposed "venom clade" Toxicofera of all venomous reptiles.
The Gila monster is a species of venomous lizard native to the Southwestern United States and the northwestern Mexican state of Sonora. It is a heavy, typically slow-moving reptile, up to 56 centimetres (22 in) long, and it is the only venomous lizard native to the United States. Its venomous close relatives, the four beaded lizards inhabit Mexico and Guatemala. The Gila monster is sluggish in nature, so it is not generally dangerous and very rarely poses a real threat to humans. However, it has a fearsome reputation and is sometimes killed in spite of the species being protected by state law in Arizona.
Gobiderma is an extinct genus of Late Cretaceous lizard whose fossils are known from the Gobi Desert in southern Mongolia. It was first discovered as a result of a joint Polish-Mongolian Paleontological Expedition, and formally named in 1984. In life, it probably resembled lizards of the genus Heloderma to a large degree, though its skull was more elongated than lizards of that genus.
The Guatemalan beaded lizard, also called commonly the Motagua Valley beaded lizard, is a highly endangered species of beaded lizard, a venomous lizard in the family Helodermatidae. The species is endemic to the dry forests of the Motagua Valley in southeastern Guatemala, an ecoregion known as the Motagua Valley thornscrub. It is the only allopatric beaded lizard species, separated from the nearest population by 250 km (160 mi) of unsuitable habitat. The Guatemalan beaded lizard is the rarest and most endangered species of beaded lizard, and it is believed that fewer than 200 individuals of this animal exist in the wild, making it one of the most endangered lizards in the world. In 2007, it was transferred from Appendix II to Appendix I of CITES due to its critical conservation status.
The Gadsden County paleontological sites are assemblages of Early Miocene invertebrates and vertebrates occurring in Gadsden County, Florida, United States.
Monstersauria is a clade of anguimorph lizards, defined as all taxa more closely related to Heloderma than Varanus. It includes Heloderma, as well as several extinct genera, such as Estesia, Primaderma and Gobiderma, but it was found to be polyphyletic in the most recent and complete squamate phylogenetic analysis by Reeder et al. (2015).
Helothermine is a toxin from the venom of the Mexican beaded lizard Heloderma horridum horridum. Helothermine inhibits ryanodine receptors, calcium channels and potassium channels. Helothermine can cause lethargy, partial paralysis of rear limbs and lowering of the body temperature.
Shinisauria is a clade or evolutionary grouping of anguimorph lizards that includes the living Chinese crocodile lizard Shinisaurus and several of its closest extinct relatives. Shinisauria was named in 2008 by Jack Lee Conrad as a stem-based taxon to include all anguimorphs more closely related to Shinisaurus than to Anguis fragilis, Heloderma suspectum or Varanus varius. Several recent phylogenetic analyses of lizard evolutionary relationships place Shinisauria in a basal position within the clade Platynota, which also includes monitor lizards, helodermatids, and the extinct mosasaurs. Shinisaurians were once thought to be closely related to the genus Xenosaurus, but they are now considered distant relatives within Anguimorpha. The fossil record of shinisaurians extends back to the Early Cretaceous with Dalinghosaurus, which is from the Aptian aged Yixian Formation of China. Two other extinct shinisaurians are currently known: Bahndwivici from the Eocene of Wyoming and Merkurosaurus from the Late Oligocene of Germany and the Early Miocene of the Czech Republic. An indeterminate shinisaurian is known from an isolated tail found in the Eocene aged Messel pit in Germany.
The Rio Fuerte beaded lizard is a venomous species of beaded lizard in the family Helodermatidae. It is found in the tropical forests and shrublands of western Mexico, specifically around the Rio Fuerte and Rio Mayo basins. It is often found in or near abandoned mammal burrows and sources of water.
Heloderma alvarezi, the Chiapan beaded lizard or black beaded lizard, is a species of lizard of the Helodermatidae family. It is found in Mexico and Guatemala.
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