Aigialosauridae is a family of Late Cretaceous semiaquatic pythonomorph lizards closely related to the mosasaurs. Regarded by some paleontologists as a distinct monophyletic group and by others as an adaptive grade within the basal mosasauroids, recent molecular and morphological data suggests that they are the oldest known members of the lineage leading to the mosasaurs.
Dallasaurus is a basal mosasauroid from the Upper Cretaceous of North America. Along with Russellosaurus, Dallasaurus is one of the two oldest mosasauroid taxa currently known from North America. It is also one of the smallest known mosasaurines, measuring approximately 1 m (3.3 ft) in length.
Judeasaurus is an extinct genus of small, aquatic varanoid lizard related to the mosasauroids. The only known specimen is from the Late Cretaceous of the Judean Hills around Israel and the West Bank, though its exact provenance is uncertain.
Adriosaurus is an extinct genus of squamate which lived in what is now Slovenia and other parts of Europe during the Late Cretaceous. It was small, snake-like reptile, with type species measuring up to 30 cm (12 in) in length. This is the first fossil record of vestigial limbs in lizards. It lost its manus and forearm completely in order to elongate its axial skeleton. These unique anatomical features led to discussions of the evolutionary patterns of limb reduction in Squamata.
Palmulasaurus is a genus of polycotylid plesiosaur from the Turonian Tropic Shale of Utah. It was originally described as Palmula, but the name was occupied by a genus of Cretaceous foraminifer first described in 1833.
Pahasapasaurus is a genus of plesiosaur. It was an early polycotylid plesiosaur from the Cenomanian of South Dakota, USA. Distinctive features of the taxon include elongate epipodial bones and the nature of the palate bones. The type species is P. haasi.
Tethysaurus is an extinct genus of tethysaurine mosasauroid from the Early Turonian period. The only species is Tethysaurus nopcsai.
Carsosaurus is a genus of extinct amphibious reptiles, in the mosasaur superfamily, containing only the species Carsosaurus marchesetti. It is known from a single individual that lived during the Upper Cretaceous in what is now Slovenia. The specimen is well-preserved, containing many different bones as well as some skin impressions and sternal cartilage. While more remains are needed to be certain, it is generally thought to belong to Aigialosauridae. In life, it was an amphibious creature that spent most of its time on land, although its later relatives would become fully aquatic.
Eidolosaurus was a genus of mosasauroid from the Late Cretaceous period of Slovenia.
Vallecillosaurus is an extinct genus of mosasauroid from the Late Cretaceous period, that lived in Mexico, in the state of Nuevo León. It was a relatively small reptile measuring less than 1 m (3.3 ft) long.
Aigialosaurus is an extinct genus of Late Cretaceous marine or semiaquatic lizard classified as part of the family Aigialosauridae within the Mosasauroidea. Exclusively found in deposits of Cenomanian age near Hvar, Croatia, the genus contains one valid species, A. dalmaticus. According to recent molecular and morphological data, Aigialosaurus is the oldest known member of the lineage leading to large Cretaceous marine reptiles called mosasaurs, a group most closely related to snakes among living squamates. It was a relatively small reptile with a complete specimen measuring 65 cm (2.13 ft) long.
Opetiosaurus is an extinct genus of Late Cretaceous marine or semiaquatic lizard classified as part of the family Aigialosauridae within the Mosasauroidea. Exclusively found in deposits of Cenomanian age near Hvar, Croatia, the genus contain one valid species, O. bucchichi. It was a small reptile measuring 1 metre (3.3 ft) long.
Haasiasaurus is an extinct genus of early mosasaur, originally named "Haasia" by M. J. Polcyn et al., in honour of the palaeontologist Georg Haas. Haasiasaurus was one of the oldest cenomanian mosasaur measuring 1 metre (3.3 ft) long. The genus contains the species Haasiasaurus gittelmani, which was found in the Cenomanian 100 million years ago rocks near Ein Yabrud, in the Palestinian West Bank, approximately 20 kilometres (12 mi) north of Jerusalem.
Acteosaurus is an extinct genus of aquatic lizard that lived in the upper Cretaceous period. Its species, A. tommasinii and A. crassicostatus, were described in 1860 and 1993. Though A. crassicostatus is probably a junior synonym for Adriosaurus suessi, A. tommasinii was found to be similar to coniasaurs, mosasauroids, and a sister taxon to modern snakes in 2010.
Pannoniasaurus is an extinct genus of tethysaurine mosasauroid known from the Late Cretaceous Csehbánya Formation of Hungary. It contains a single species, Pannoniasaurus inexpectatus, dubbed "unexpected" because it was discovered in freshwater sediments, unlike other mosasaurs, which were marine predators. It was a medium-sized mosasaur, reaching up to 6 metres (20 ft) in length.
Coniasaurus is an extinct genus of Late Cretaceous marine squamates that range in age from Cenomanian to Santonian. It was first described by Richard Owen in 1850 from lower Cenomanian chalk deposits in southeast England (Sussex). Two species have been described from this genus: C. crassidens, known from Cenomanian to Santonian deposits from southeast England, Germany and North America, and C. gracilodens from the Cenomanian of southeast England.
This timeline of mosasaur research is a chronologically ordered list of important fossil discoveries, controversies of interpretation, and taxonomic revisions of mosasaurs, a group of giant marine lizards that lived during the Late Cretaceous Epoch. Although mosasaurs went extinct millions of years before humans evolved, humans have coexisted with mosasaur fossils for millennia. Before the development of paleontology as a formal science, these remains would have been interpreted through a mythological lens. Myths about warfare between serpentine water monsters and aerial thunderbirds told by the Native Americans of the modern western United States may have been influenced by observations of mosasaur fossils and their co-occurrence with creatures like Pteranodon and Hesperornis.
Dolichosauridae is a family of Cretaceous aquatic ophidiomorphan lizards closely related to the snakes and mosasaurs.
Portunatasaurus is a genus of mosasauroid squamate that lived during the Late Cretaceous period in what is now Croatia. It contains a single species, P. krambergeri, recovered from the Adriatic-Dinaric Carbonate Platform. It was a relatively small reptile, reaching 1 m (3.3 ft) in length.
