Tethysaurinae Temporal range: Late Cretaceous | |
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Skeleton of Tethysaurus . | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Order: | Squamata |
Clade: | † Mosasauria |
Family: | † Mosasauridae |
Clade: | † Russellosaurina |
Subfamily: | † Tethysaurinae Makádi et al., 2012 |
Genera | |
The Tethysaurinae are a subfamily of mosasaurs, a diverse group of Late Cretaceous marine squamates. Members of the subfamily are informally and collectively known as "tethysaurines" and have been recovered from North America and Africa. [1] Only two tethysaurine genera are known, Pannoniasaurus and Tethysaurus . The genera Yaguarasaurus and Russellosaurus were previously considered tethysaurines until they were grouped with Romeosaurus in the new subfamily Yaguarasaurinae. [2] A possible member of this clade (subfamily) is a mosasaur specimen known from a maxilla fragment, found in 1960 in the Czech Republic (then Czechoslovakia), in Dolní Újezd near Litomyšl. [3]
Like the closely related yaguarasaurines, all tethysaurines were plesiopedal (meaning primitive and not as well adapted to marine life as later mosasaurs). They generally retained relatively small sizes compared to later giant mosasaurs. The tethysaurines appeared during the Turonian and went extinct in the Santonian, possibly outcompeted by more derived mosasaurs. The etymology of this group derives from the genus Tethysaurus ( Tethys from the Greek goddess of the sea and sauros, Greek for "lizard").
Tethysaurines were primitive and comparatively small to medium-sized mosasaurs that lived during the earlier stages of mosasaur evolutionary history. Tethysaurus itself is approximately 3 metres long, while Pannoniasaurus might have reached lengths of 6 metres. They had a plesiopedal limb condition, meaning that they were not as well adapted to marine life as later mosasaurs and probably kept to shallow bodies of water. Pannoniasaurus is the only known mosasaur recovered from freshwater deposits. [4]
Makádi et al. (2012) [4] originally diagnosed the Tethysaurinae as all mosasaurs descended from the recentmost common ancestor of Tethysaurus nopscai and Russellosaurus coheni . By this definition, the Yaguarasaurinae would be sunk into this subfamily since Russellosaurus is now considered a yaguarasaurine. Unambiguous character states were listed as follows: "predental rostrum absent; premaxilla-maxilla suture ends anterior to or level with the midline of the fourth maxillary tooth; nearly straight frontoparietal suture; quadrate alar concavity shallow; elongated stapedial pit (at least three times longer than wide); quadrate distal condyle saddle-shaped, upward deflection of quadrate distal condyle absent; mandibular glenoid formed mainly by articular; cervical synapophyses extend below ventral border of centrum; dorsoventrally compressed centra in precaudal vertebrae; two sacrals with large ribs/transverse processes subcircular/oval in cross-section; facet for ilium on tip of sacral transverse processes; very elongated (two times longer than wide) pontosaur-like caudal centra; anteroposteriorly narrow scapula; ilium with posterior iliac process with compressed dorsal end bearing longitudinal grooves and ridges, and spoon-shaped preacetabular process overlapping the pubis".
The subfamily name is derived from Tethysaurus due to Tethysaurus being the best-represented genus of the subfamily and being known from multiple partial skeletons. [4]
The original definition of the Tethysaurinae was as all mosasaurs descended from the recentmost common ancestor of Tethysaurus nopscai and Russellosaurus coheni . The cladogram below follows Makádi et al. (2012) [4] and the then assumed internal relationships of the Tethysaurinae.
Tethysaurinae | |
Yaguarasaurus and Russellosaurus are today considered part of the Yaguarasaurinae instead, which is defined as the most recent common ancestor of Russellosaurus, Romeosaurus , and Yaguarasaurus, and all of its descendants. [2]
Tethysaurinae
Mosasaurs are an extinct group of large aquatic reptiles within the family Mosasauridae that lived during the Late Cretaceous. Their first fossil remains were discovered in a limestone quarry at Maastricht on the Meuse in 1764. They belong to the order Squamata, which includes lizards and snakes.
Selmasaurus is an extinct genus of marine lizard belonging to the mosasaur family. It is classified as part of the Plioplatecarpinae subfamily alongside genera like Angolasaurus and Platecarpus. Two species are known, S. russelli and S. johnsoni; both are exclusively known from Santonian deposits in the United States.
The Mosasaurinae are a subfamily of mosasaurs, a diverse group of Late Cretaceous marine squamates. Members of the subfamily are informally and collectively known as "mosasaurines" and their fossils have been recovered from every continent except for South America.
The Tylosaurinae are a subfamily of mosasaurs, a diverse group of Late Cretaceous marine squamates. Members of the subfamily are informally and collectively known as "tylosaurines" and have been recovered from every continent except for South America. The subfamily includes the genera Tylosaurus, Taniwhasaurus, and Kaikaifilu, although some scientists argue that only Tylosaurus and Taniwhasaurus should be included.
Plioplatecarpinae is a subfamily of mosasaurs, a diverse group of Late Cretaceous marine squamates. Members of the subfamily are informally and collectively known as "plioplatecarpines" and have been recovered from all continents, though the occurrences in Australia remain questionable. The subfamily includes the genera Latoplatecarpus, Platecarpus, Plioplatecarpus and Plesioplatecarpus.
The Halisaurinae are a subfamily of mosasaurs, a group of Late Cretaceous marine lizards. They were small to medium-sized, ranging from just under 3 meters in Eonatator sternbergi to as much as 8 or 9 meters in Pluridens serpentis. They tended to have relatively slender jaws and small, numerous teeth, suggesting a diet of small fish and other prey. Although the skeleton is primitive compared to other Mosasauridae in many respects, halisaurines had the distinctive hypocercal tail of other mosasaurids suggesting good swimming ability, and they persisted alongside other mosasaurs until the end of the Cretaceous. The earliest known remains of halisaurines occur in rocks of Santonian age and the subfamily persists until the latest Maastrichtian. Halisaurines are known from North and South America, Europe, Asia and Africa, indicating a more or less global distribution in the Late Cretaceous. Four genera are currently recognized: Eonatator, Halisaurus, Phosphorosaurus and Pluridens.
Eonatator is an extinct genus of marine lizard belonging to the mosasaur family. It is a close relative of Halisaurus, and part of the same subfamily, the Halisaurinae. It is known from the Late Cretaceous of North America, Colombia and Sweden. Originally, this taxon was included within Halisaurus, but was placed in its own genus, which also led to the subfamily Halisaurinae being created for the two genera.
Russellosaurus is an extinct genus of tethysaurine mosasauroid from the Late Cretaceous of North America. The genus was described from a skull discovered in an exposure of the Arcadia Park Shale at Cedar Hill, Dallas County in the south-central part of the DFW Metroplex in Texas, United States. The skull was found in 1992 by a member of the Dallas Paleontological Society, who then donated to the museum. Other fragmentary specimens of Russelosaurus have been recovered from the slightly older Kamp Ranch Limestone at two other localities in the Dallas area.
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.
Clidastes is an extinct genus of marine lizard belonging to the mosasaur family. It is classified as part of the Mosasaurinae subfamily, alongside genera like Mosasaurus and Prognathodon. Clidastes is known from deposits ranging in age from the Coniacian to the early Campanian in the United States.
Plioplatecarpus is a genus of mosasaur lizard. Like all mosasaurs, it lived in the late Cretaceous period, about 73-68 million years ago.
Anatosuchus is an extinct genus of notosuchian crocodyliforms discovered in Gadoufaoua, Niger, and described by a team of palaeontologists led by the American Paul Sereno in 2003, in the Journal of Vertebrate Paleontology.
Qianosuchus is an extinct genus of aquatic poposauroid archosaur from the middle Triassic (Anisian) Guanling Formation of Pan County, China. It is represented by two nearly complete skeletons and a crushed skull preserved in the limestone. Qianosuchus was at least 3 metres long, and had several skeletal adaptations which indicate a semi-marine lifestyle, similar to modern-day saltwater crocodiles. These adaptations have not been seen in any other archosaur from the Triassic.
Taniwhasaurus is an extinct genus of mosasaurs that lived during the Campanian stage of the Late Cretaceous. It is a member of the subfamily Tylosaurinae, a lineage of mosasaurs characterized by a long toothless conical rostrum. Two valid species are attached to the genus, T. oweni and T. antarcticus, known respectively from the fossil record of present-day New Zealand and Antarctica. Two other species have been nominally classified within the genus, T. 'capensis' and T. 'mikasaensis', recorded in present-day South Africa and Japan, but their attribution remains problematic due to the fragmentary state of their fossils. The generic name literally means "taniwha lizard", referring to a supernatural aquatic creature from Māori mythology.
Peloroplites is a monospecific genus of nodosaurid dinosaur from Utah that lived during the Late Cretaceous in what is now the Mussentuchit Member of the Cedar Mountain Formation. The type and only species, Peloroplites cedrimontanus, is known from a partial skull and postcranial skeleton. It was named in 2008 by Kenneth Carpenter and colleagues. Peloroplites was 6 metres long and weighed 2 tonnes, making it one of the largest known nodosaurids, and came from a time when ankylosaurids and nodosaurids were attaining large sizes.
Tethysaurus is an extinct genus of tethysaurine mosasauroid from the Early Turonian period. The only species is Tethysaurus nopcsai.
Pannoniasaurus is an extinct genus of tethysaurine mosasauroid known from the Late Cretaceous Csehbánya Formation and Ajka Coal 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.
The Yaguarasaurinae are a subfamily of mosasaurs, a diverse group of Late Cretaceous marine squamates. Members of the subfamily are informally and collectively known as "yaguarasaurines" and have been recovered from North and South America and Europe. Three genera, Yaguarasaurus, Russellosaurus and Romeosaurus are known. Yaguarasaurus and Russellosaurus were previously considered part of the Tethysaurinae until they were grouped with Romeosaurus as yaguarasaurines.
Europelta is a monospecific genus of nodosaurid dinosaur from Spain that lived during the Early Cretaceous in what is now the lower Escucha Formation of the Teruel Province. The type and only species, Europelta carbonensis, is known from two associated partial skeletons, and represents the most complete ankylosaur known from Europe. Europelta was named in 2013 by James I. Kirkland and colleagues. Europelta has an estimated length of 5 metres and weight of 1.3 tonnes, making it the largest member of the clade Struthiosaurini.