| Estesia Temporal range: Late Cretaceous, | |
|---|---|
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| Cast of skull from the American Museum of Natural History | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | Squamata |
| Clade: | Goannasauria (?) |
| Genus: | † Estesia |
| Species: | †E. mongoliensis |
| Binomial name | |
| †Estesia mongoliensis | |
Estesia (in honour of Richard Estes) is an extinct genus of Late Cretaceous anguimorph lizard found in the Gobi Desert in Mongolia.
It was discovered in June 1990 by a joint expedition made up of Mongolian and American palaeontologists, and described in 1992 by Mark Norell, Malcolm McKenna and Michael Novacek. This animal is of interest to palaeontologists, not only because it is close to the lineage of modern Gila monsters ( Heloderma ), but also because its dentition shows evidence that it was venomous.
The type species is E. mongoliensis, after Mongolia, where it was found.
Material for Estesia has been collected in various localities in the Gobi Desert, including the Barun Goyot Formation, the Djadochta Formation and Ukhaa Tolgod.
In the description, Estesia was assigned to Varanoidea, as the sister group to Varanidae, based on skull characters. However, the new material found in 1993 provided evidence that Estesia was not closely related to modern varanids, but rather a distant relative of Gila monsters. The phylogenetic analysis presented by Norell and Gao (1997) actually supported the creation of a new group that included modern Gila monsters and extinct pre-historic forms, the Monstersauria.
The teeth of Estesia were sharp and recurved, like in modern varanoids. These teeth possess longitudinal grooves that run both from the anterior and posterior tooth surfaces during the entire tooth length. Similar characteristics are present in the teeth of Gila monsters.
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Minotaurasaurus is a monospecific genus of ankylosaurid dinosaur that lived in Mongolia during the Late Cretaceous in what is now the Djadochta Formation. The type and only species, Minotaurasaurus ramachandrani, is known from two skulls, a cervical vertebra and a cervical half ring. It was named and described in 2009 by Clifford Miles and Clark Miles. The first fossils of Minotaurasaurus were illegally exported out of Mongolia.It has been suggested to be a synonym of Tarchia but more recent publications consider it as a distinct genus.
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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.
Telmasaurus is an extinct genus of varanoid lizard from the Late Cretaceous of Mongolia. Fossils have been found from the Djadokha and Barun Goyot Formations that date between the early and middle Campanian stage from approximately 80 to 75 million years ago. The type species Telmasaurus grangeri was named in 1943.
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Phrynosomimus is an extinct genus of iguanian lizard from the Late Cretaceous of Mongolia belonging to the extinct family Priscagamidae. The type species Phrynosomimus asper was named in 1996. Fossils have been found in the Barun Goyot and Djadochta formations and include several complete skulls. Phrynosomimus has a short, triangular skull with bony spikes projecting from the back, stemming from the squamosal and parietal bones. These spikes give it a similar appearance to the modern horned lizard Phrynosoma and inspire its name, which means "Phrynosoma mimic." Like other priscagamids it has an acrodont dentition, meaning that its teeth grow from the margins of the jaws rather than their inner surfaces, as is the case for the pleurodont dentitions of most lizards.
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