Sauroposeidon is a genus of sauropod dinosaur known from several incomplete specimens including a bone bed and fossilized trackways that have been found in the American states of Oklahoma, Wyoming, and Texas.
Tenontosaurus is a genus of medium- to large-sized ornithopod dinosaur. The genus is known from the late Aptian to Albian ages of the middle Cretaceous period sediments of western North America, dating between 115 and 108 million years ago.
Astrodon is a dubious genus of large herbivorous sauropod dinosaur, related to Brachiosaurus, that lived in what is now the eastern United States during the Early Cretaceous period. Its fossils have been found in the Arundel Formation, which has been dated through palynomorphs to the Albian about 112 million years ago. Adults are estimated to have been more than 9 m (30 ft) high and 15 to 18 m long.
The Antlers Formation is a stratum which ranges from Arkansas through southern Oklahoma into northeastern Texas. The stratum is 150 m (490 ft) thick consisting of silty to sandy mudstone and fine to coarse grained sandstone that is poorly to moderately sorted. The stratum is cemented with clay and calcium carbonate. In places the sandstone may be conglomeratic or ferruginous.
Paramacellodus is an extinct genus of scincomorph lizards from the Early Cretaceous of England the Late Jurassic of Portugal and the western United States. The type species, Paramacellodus oweni, was named in 1967 from the Purbeck Formation in Dorset, England. Additional material referable to a species of Paramacellodus, possibly P. oweni, has been described from the Morrison Formation, specifically in Como Bluff, Wyoming, and Dinosaur National Monument, Utah. Paramacellodus belongs to an extinct family of scincomorphs called Paramacellodidae, which spanned most of Laurasia during the Late Jurassic and Early Cretaceous and represented one of the earliest evolutionary radiations of lizards.
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.
Obamadon is an extinct genus of polyglyphanodontian lizards from the Late Cretaceous of North America. Fossils have been found in the Hell Creek Formation of Montana and the Lance Formation of Wyoming. Researchers describe it as being distinguished by its "tall, slender teeth with large central cusps separated from small accessory cusps by lingual grooves." The type species was named Obamadon gracilis after United States president Barack Obama, "in reference to the tall, straight teeth, and the manner in which Mr. Obama has acted as a role model of good oral hygiene for the world." According to Nicholas R. Longrich of Yale University, the creature "was probably a foot long, [and] with these tall, slender teeth it used to eat insects and plant matter."
Desertiguana is an extinct genus of lizard in the family Phrynosomatidae. It is a monotypic genus represented by the type species Desertiguana gobiensis from the Late Cretaceous Barun Goyot Formation of Mongolia. Desertiguana gobiensis is known from a single left lower jaw.
Chthonophis is an extinct genus of amphisbaenian lizard with only one known species, Chthonophis subterraneus, from the earliest Paleocene of northeastern Montana. Chthonophis was named in 2015 on the basis of a partial lower jaw from an outcrop of the Fort Union Formation in the Bug Creek Anthills. The surfaces of the bone are well-rounded, suggesting that the remains had been partially digested by another animal before the jaw had been buried and fossilized. Chthonophis is the oldest known amphisbaenian, yet phylogenetic analysis shows that it was not the most basal. Longrich et al. (2015) classified Chthonophis in its own family, Chthonophidae, finding it to be more derived than Rhineuridae but more basal than other clades such as Blanidae and Amphisbaenidae. The existence of a derived amphisbaenian soon after the Cretaceous-Paleogene extinction event suggests that Amphisbaenia has its origins in the Cretaceous, although no Cretaceous amphisbaenians are currently known. Below is a cladogram from Longrich et al. (2015) showing the phylogenetic relationships of Chthonophis:
Asprosaurus is an extinct genus of anguimorph lizard from the Late Cretaceous of South Korea. Named in 2015 from the Seonso Conglomerate Formation, the type species Asprosaurus bibongriensis is the first Mesozoic lizard to have been discovered on the Korean peninsula. Because Asprosaurus is known only from fragmentary material, its relationships with other lizards are uncertain. However, features of the lower jaw suggest that it may be a member of a clade called Monstersauria, which includes the living Gila monster.
Pariguana is an extinct genus of iguanid lizard from the Late Cretaceous of western North America. It is known from a single type species, Pariguana lancensis, named in 2012 on the basis of a partial lower jaw from the Lance Formation in eastern Wyoming. This jaw bone comes from a layer dated approximately 650,000 years before the Cretaceous–Paleogene extinction event. Pariguana is the oldest definitive iguanid from North America, and may represent the first stage of the iguanian evolutionary radiation from Asia into North America.
Gueragama is an extinct genus of iguanian lizard from the Late Cretaceous of Brazil. It belongs to a group of iguanians called Acrodonta, whose living members include chameleons and agamids and are currently restricted to the Old World. Gueragama is the only acrodont known from South America, providing evidence that the group once ranged across much of Gondwana and only became restricted to the Old World after the supercontinent broke apart. The type species, Gueragama sulamericana, was named in 2015 on the basis of an isolated lower jaw from the Turonian- to Campanian-age Goio-Erê Formation in the Bauru Basin, which was deposited in a desert environment. Unlike modern acrodontans, whose teeth implant on the margins of the jaws, Gueragama has teeth that implant along the inner surface of the lower jaw, a feature common in most non-acrodontan lizards and characteristic of the second major group of iguanians, Pleurodonta. The non-acrodont dentition of Gueragama is evidence of its basal position within Acrodonta, and is shared with the taxon of Late Cretaceous acrodontan relatives, the family Priscagamidae.
Paramacellodidae is an extinct family of scincomorph lizards that first appeared in the Middle Jurassic around 170 million years ago (Ma) and became extinct in the Early Cretaceous about 100 Ma. It was one of the earliest groups of lizards to have undergone an evolutionary radiation, with members found across the supercontinent Laurasia. The phylogenetic relationships and constituent species of Paramacellodidae are uncertain. Many studies regard it to be closely related to Scincoidea, a large group that includes skinks and their closest extinct relatives, and possibly also to Cordyoidea, a group that includes spinytail lizards and relatives. Like modern skinks, paramacelloidids had rectangular bony plates called osteoderms covering most of their bodies, including their backs, undersides, and tails. They also had short and robust limbs.
Ptilotodon is an extinct genus of teiid lizard from the Early Cretaceous of Oklahoma. The type and only known species is Ptilotodon wilsoni, named in 2002 on the basis of a single lower jaw with four teeth found in the Antlers Formation. The small size of the specimen may be an indication that it belonged to a juvenile.
Sharovisaurus is an extinct genus of scincomorph lizard from the Late Jurassic of Kazakhstan. It belongs to an extinct family of Mesozoic lizards called Paramacellodidae, which existed across most of Laurasia during the Late Jurassic and Early Cretaceous. The type and only species is Sharovisaurus karatauensis, named in 1984 on the basis of a nearly complete articulated skeleton from the Oxfordian-aged Karabastau Formation. The back and tail of the skeleton are covered in rectangular-shaped bony plates called osteoderms, which have a similar arrangement to those of modern skinks. At 138 millimetres (5.4 in) in length from the tip of its snout to the base of its tail, Sharovisaurus was one of the largest paramacellodids. Like other paramacellodids it had relatively short and robust limbs in comparison to the rest of its body.
Bharatagama is an extinct genus of lepidosaur from the Early Jurassic of India. It is sugguested to be one of the oldest known lizards and the oldest known iguanian. The type and only species is Bharatagama rebbanensis, named in 2002. Over one hundred fossils of Bharatagama have been found in the Kota Formation, which outcrops in the Pranhita–Godavari Basin and dates back to about 190 million years ago (Ma). Despite its abundance, Bharatagama is known only from isolated jaw bones mixed together in microvertebrate assemblages with equally fragmentary remains of fish, sphenodontians, dinosaurs, crocodylomorphs, and mammals. These fossils represent all stages of development, from hatchlings to adults. The total length of the skull in adult specimens is estimated to have been about 15 millimetres (0.59 in). Later analysis suggested that the taxon might be a member of Rhynchocephalia.
Becklesius is an extinct genus of Paramacellodid lizard known from the Late Jurassic to Early Cretaceous of Europe, the type species, B. hoffstetteri is known from Kimmeridgian aged sediments of the Alcobaça Formation in Portugal. An indeterminate species is known from Berriasian aged sediments of the Lulworth Formation in the UK. Another species B. cataphractus is known from Barremian aged sediments of the Una locality, part of the La Huérguina Formation, Spain.
Durotrigia is a genus of extinct lizard from the Early Cretaceous of southern England. The type and only species is Durotrigia triconidens, named in 1967 by R. Hoffstetter for jaw material in a review of the lizard fauna of the Berriasian Lulworth Formation. The genus was found in the Mammal Bed near the base of the formation alongside the other lizards Paramacellodus, Becklesius, Pseudosaurillus, Dorsetisaurus, Saurillus and Parviraptor. Durotrigia is likely a genus within the family Globauridae.
Parasaurillus is a genus of extinct lizard from the Early Cretaceous of southern England. The type and only species is Parasaurillus pseudobtusus, named in 2002 by Susan E. Evans and Belinda Searle for extensive jaw and tooth material that has previously been classified as either Saurillus obtusus or Pseudosaurillus from the Berriasian Lulworth Formation. The taxon was found in the Mammal Bed near the base of the formation alongside the other lizards Becklesius, Dorsetisaurus, Durotrigia, Paramacellodus, Pseudosaurillus, Parviraptor and Saurillus obtusus. It is likely closely related to Scincoidea, moreso than other contemporary taxa.
Pseudosaurillus is a genus of extinct lizard from the Early Cretaceous of southern England. The type and only species is Pseudosaurillus becklesi, named in 1967 by R. Hoffstetter limited jaw and tooth material from the Berriasian Lulworth Formation. A large amount of material that was additionally referred to Saurillus by Hoffstetter was reassigned to Pseudosaurillus in 1983 by Estes, but this has since been reclassified within its own genus Parasaurillus by Susan E. Evans and Belinda Searle in 2002. The taxon was found in the Mammal Bed near the base of the formation alongside the other lizards Becklesius, Dorsetisaurus, Durotrigia, Paramacellodus, Parasaurillus, Parviraptor and Saurillus. Like Becklesius, Pseudosaurillus may be a member of the family Paramacellodidae.
