The Iguanidae are a family of lizards composed of iguanas and related species.
Xenosauridae is a family of anguimorph lizards whose only living representative is the genus Xenosaurus, which is native to Central America. Xenosauridae also includes the extinct genera Exostinus and Restes. Also known as knob-scaled lizards, they have rounded, bumpy scales and osteoderms. Most living species prefer humid, rocky habitats, although they are widespread within their native regions, with some inhabiting semi-arid scrub environments. They are carnivorous or insectivorous, and give birth to live young.
The Varanidae are a family of lizards in the superfamily Varanoidea. The family, a group of carnivorous and frugivorous lizards, includes the living genus Varanus, the extinct Megalania, and a number of other extinct taxa. Varanus includes the Komodo dragon, crocodile monitor, savannah monitor, the goannas of Australia and Southeast Asia, and various other species with a similarly distinctive appearance. Their closest living relatives are the anguid and helodermatid lizards.
Troodontidae is a family of bird-like theropod dinosaurs. During most of the 20th century, troodontid fossils were few and incomplete and they have therefore been allied, at various times, with many dinosaurian lineages. More recent fossil discoveries of complete and articulated specimens, have helped to increase understanding about this group. Anatomical studies, particularly studies of the most primitive troodontids, like Sinovenator, demonstrate striking anatomical similarities with Archaeopteryx and primitive dromaeosaurids, and demonstrate that they are relatives comprising a clade called Paraves.
Compsognathus is a genus of small, bipedal, carnivorous theropod dinosaur. Members of its single species Compsognathus longipes could grow to around the size of a turkey. They lived about 150 million years ago, during the Tithonian age of the late Jurassic period, in what is now Europe. Paleontologists have found two well-preserved fossils, one in Germany in the 1850s and the second in France more than a century later. Today, C. longipes is the only recognized species, although the larger specimen discovered in France in the 1970s was once thought to belong to a separate species and named C. corallestris.
Microraptor is a genus of small, four-winged paravian dinosaurs. Numerous well-preserved fossil specimens have been recovered from Liaoning, China. They date from the early Cretaceous Jiufotang Formation, 120 million years ago. Three species have been named, though further study has suggested that all of them represent variation in a single species, which is properly called M. zhaoianus. Cryptovolans, initially described as another four-winged dinosaur, is usually considered to be a synonym of Microraptor.
Sinornithosaurus is a genus of feathered dromaeosaurid dinosaur from the early Cretaceous Period of the Yixian Formation in what is now China. It was the fifth non–avian feathered dinosaur genus discovered by 1999. The original specimen was collected from the Sihetun locality of western Liaoning. It was found in the Jianshangou beds of the Yixian Formation, dated to 124.5 million years ago. Additional specimens have been found in the younger Dawangzhangzi bed, dating to around 122 million years ago.
Animantarx is a genus of nodosaurid ankylosaurian dinosaur from the Upper Cretaceous of western North America. Like other nodosaurs, it would have been a slow-moving quadrupedal herbivore covered in heavy armor scutes, but without a tail club. The skull measures approximately 25 cm in length, suggesting the animal as a whole was no more than 3 meters long.
Citipati is a genus of oviraptorid dinosaur that lived in Asia during the Late Cretaceous period, about 75 million to 71 million years ago. It is mainly known from the Ukhaa Tolgod locality at the Djadokhta Formation, where the first remains were collected during the 1990s. The genus and type species Citipati osmolskae were named and described in 2001. A second species from the adyacent Zamyn Khondt locality may also exist. Citipati is one of the best-known oviraptorids thanks to a number of well-preserved specimens, including individuals found in brooding positions atop nests of eggs, though most of them were initially referred to the related Oviraptor. These nesting specimens have helped to solidify the link between non-avian dinosaurs and birds.
Shenzhousaurus is a genus of basal ornithomimosaur from the Lower Cretaceous of China.
Jacques Armand Gauthier is an American vertebrate paleontologist, comparative morphologist, and systematist, and one of the founders of the use of cladistics in biology.
Tsaagan is a genus of carnivorous dromaeosaurid theropod dinosaur from the Djadokhta Formation of the late Cretaceous of Mongolia.
Litargosuchus is a sphenosuchian crocodylomorph, a basal member of the crocodylomorph clade from the Early Jurassic of South Africa. Its genus name Litargosuchus is derived from Greek meaning "fast running crocodile" and its species name leptorhynchus refers to its gracile snout. Litargosuchus, along with all of South Africa's crocodylomorph taxa, are confined to the upper Elliot Formation (UEF) in South Africa.
Linheraptor is a genus of dromaeosaurid dinosaur which lived in what is now China in the Late Cretaceous. It was named by Xu Xing and colleagues in 2010, and contains the species Linheraptor exquisitus. This bird-like dinosaur was less than 2 m (6.5 ft) long and was found in Inner Mongolia. It is known from a single, nearly complete skeleton.
Aiolosaurus is an extinct genus of monitor lizard from the Late Cretaceous of Mongolia. The type and only species, Aiolosaurus oriens, was named in 2000 from Ukhaa Tolgod, a rich fossil site in the Campanian-age Djadochta Formation.
Glyptosaurinae is an extinct subfamily of anguid lizards that lived in the Northern Hemisphere during the Late Cretaceous and the Paleogene.
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 as a stem-based taxon to include all anguimorphs more closely related to Shinisaurus than to any other lizard. 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 Yixian Formation of China. Two other extinct shinisaurians are currently known: Bahndwivici from the Eocene of Wyoming and Merkurosaurus from the Early Miocene of the Czech Republic.
Carusioidea is a clade of lizards that includes the family Xenosauridae from Central America and the extinct genus Carusia from the Late Cretaceous of Mongolia. It was named in 1998 after a sister-group relationship was found between Carusia and Xenosauridae. Phylogenetic analysis indicates that Carusioidea is the most basal clade within Anguimorpha. Features that help define Carusioidea include closely spaced orbits or eye sockets separated by fused frontal bones, a connection between the jugal and squamosal bones below the supratemporal arch, and a covering of bony osteoderms over the skull roof. Below is a cladogram showing the phylogenetic relationships of carusioids from Gao and Norell (1998):
Kevin de Queiroz is a vertebrate, evolutionary, and systematic biologist. He has worked in the phylogenetics and evolutionary biology of squamate reptiles, the development of a unified species concept and of a phylogenetic approach to biological nomenclature, and the philosophy of systematic biology.
