Betasuchus Temporal range: Late Cretaceous, | |
---|---|
Cast of the femur | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | Saurischia |
Clade: | Theropoda |
Clade: | † Ceratosauria |
Clade: | † Neoceratosauria |
Superfamily: | † Abelisauroidea |
Genus: | † Betasuchus von Huene, 1932 |
Species: | †B. bredai |
Binomial name | |
†Betasuchus bredai (Seeley, 1883 [originally Megalosaurus]) | |
Synonyms | |
|
Betasuchus is a genus of theropod dinosaur which lived during the Late Cretaceous Period. Betasuchus is, besides Orthomerus , the only dinosaur genus named from remains found in the Netherlands and the only non-avian theropod found in the Maastrichtian Beds.
Its fossil, holotype BMNH 42997 (now NHM R 42997), a part of a right femur, 312 mm long, was found in the Netherlands near Maastricht, and originally described as a new species of Megalosaurus in 1883 by Harry Seeley: M. bredai, honouring the late Dutch biologist and geologist Jacob Gijsbertus Samuël van Breda, a director of the Teylers Museum, who had collected the fossil at some time between 1820 and 1860 from the chalkstone quarry at the St Pietersberg. Van Breda did not excavate the remains himself but bought them from quarry workers who in this period dug stone from tunnels at several levels in the mountain; it is therefore impossible to determine the exact temporal horizon, apart from a general Maastrichtian; however all dinosaurian material from the formation that could be dated, stems from the latest Maastrichtian, 67-66 million years old. Only the top part of the femur has been conserved; of the distal end about eight centimetres are missing as the bone was cleanly cut in two when the chalk block containing it was sawed out. Other saw cuts damaged the head of the thigh bone. The fossil was part of his personal collection, not the museum's, and sold to the British Museum of Natural History after his death in 1867. In 1892 Belgian/Dutch/German paleontologist Johan Casimir Ubaghs referred some teeth — probably of mosasaurs — to M. bredai. Megalosaurus bredai was in 1883 the first terrestrial vertebrate named from Maastrichtian layers. [1]
A re-evaluation of the fossil by Friedrich von Huene in 1926, however, showed that it came from a genus distinct from Megalosaurus — which in the nineteenth and early twentieth century was a "wastebin taxon" where many unrelated carnivorous dinosaurs were lumped together. Von Huene thought that the fossil actually belonged to an ornithomimosaur, and gave it the provisional designation "Ornithomimidorum [sic] [2] genus b" (in Latin: genus b of the ornithomimids), being the second of two Megalosaurus species he was reallocating to Ornithomimidae, the first being M. lonzeensis as "Ornithomimidorum genus a". "Ornithomimidorum" is sometimes mistakenly listed as a dinosaur genus name. Von Huene referred to this designation when he formally renamed M. bredai in 1932, calling it Betasuchus (or "B crocodile" in Greek).
In 2017 its length was estimated to be 4 meters (13 feet).[ citation needed ]
Betasuchus is known only from a single incomplete femur, so its exact relationships with other theropods have been difficult to determine. In 1972 Dale Russell confirmed Von Huene's opinion that Betasuchus was an ornithomimosaurid, but also considered the name a nomen vanum : a failed emendation. Some workers in reference to the material still use M. bredai instead of Betasuchus. David Norman in 1990 listed Megalosaurus bredai as a nomen dubium .
Jean le Loeuff and Eric Buffetaut in 1991 concluded it was a small abelisaurid, close to Tarascosaurus and that it was distinct enough not to consider it a nomen dubium: they mentioned a more narrow femoral neck, a lack of orientation of the femoral head towards the front, the lack of an opening, or foramen, under the lesser trochanter and that the anterior face is narrower. Furthermore, at the lower end the beginnings of an anterointernal crest are visible, seeming to be homologous to the supracondylar crest of the femur of Carnotaurus . They rejected the placement within Ornithomimidae, partly because of the much higher position of the fourth trochanter on the back of the femur.
In 1997 Betasuchus was concluded by Carpenter, Russell and Baird to be related to Dryptosaurus , a tyrannosauroid. In 2004 Tykoski and Rowe placed Tarascosaurus within the Abelisauroidea.
Megalosaurus is an extinct genus of large carnivorous theropod dinosaurs of the Middle Jurassic Epoch of southern England. Although fossils from other areas have been assigned to the genus, the only certain remains of Megalosaurus come from Oxfordshire and date to the late Middle Jurassic.
Altispinax is a genus of large predatory theropod dinosaur from the Early Cretaceous period of what is now the Wadhurst Clay Formation of East Sussex, England.
Tarascosaurus is a genus of abelisaurid theropod dinosaur from Late Cretaceous of France. It was a relatively small theropod measuring 2.5–3 metres (8.2–9.8 ft) long.
Hypselosaurus is a dubious genus of titanosaurian sauropod that lived in southern France during the Late Cretaceous, approximately 70 million years ago in the early Maastrichtian. Hypselosaurus was first described in 1846, but was not formally named until 1869, when Phillip Matheron named it under the binomial Hypselosaurus priscus. The holotype specimen includes a partial hindlimb and a pair of caudal vertebrae, and two eggshell fragments were found alongside these bones. Because of the proximity of these eggshells to the fossil remains, many later authors, including Matheron and Paul Gervais, have assigned several eggs from the same region of France all to Hypselosaurus, although the variation and differences between these eggs suggest that they do not all belong to the same taxon. Hypselosaurus has been found in the same formation as the dromaeosaurids Variraptor and Pyroraptor, the ornithopod Rhabdodon, and the ankylosaurian Rhodanosaurus, as well as indeterminate bones from other groups.
Dryptosaurus is a genus of basal eotyrannosaurian theropod dinosaur that lived on the island continent of Appalachia approximately 67 million years ago during the end of the Maastrichtian age of the Late Cretaceous period. Dryptosaurus was a large, bipedal, ground-dwelling carnivore that could grow up to 7.5 metres (25 ft) long and weigh up to 756–1,500 kilograms (1,667–3,307 lb). Although it is now largely unknown outside of academic circles, the famous 1897 painting of the genus by Charles R. Knight made Dryptosaurus one of the more widely known dinosaurs of its time, in spite of its poor fossil record. First described by Edward Drinker Cope in 1866 and later renamed by Othniel Charles Marsh in 1877, Dryptosaurus is among the very first theropod dinosaurs ever known to science.
Bradycneme is a genus of theropod dinosaur from the Maastrichtian-age Upper Cretaceous Sânpetru Formation of the Hațeg Basin, Transylvania, Romania. The genus contains a single species, Bradycneme draculae, known only from a partial right lower leg, which its original describers believed came from a giant owl.
Elopteryx is a genus of, perhaps troodontid, maniraptoran theropod dinosaur based on fragmentary fossils found in late Cretaceous Period rocks of Romania. The single species, Elopteryx nopcsai, is known only from very incomplete material, and therefore is considered a nomen dubium by most paleontologists.
Calamosaurus was a genus of small theropod dinosaur from the Barremian-age Lower Cretaceous Wessex Formation of the Isle of Wight, England. It is based on two cervical vertebrae, collected by Reverend William Fox.
Teinurosaurus is a genus of carnivorous theropod dinosaur. Teinurosaurus lived during the Late Jurassic in what is now France. The type species is Teinurosaurus sauvagei. It's been estimated to be 11.4 m (37.4 ft) in length and 3.6 tonnes in weight.
Valdoraptor is a genus of theropod dinosaur from the Early Cretaceous. Its fossils were found in England. It is known only from bones of the feet. The holotype, BMNH R2559, was found near Cuckfield in layers of the Tunbridge Wells Sand Formation dating from the late Valanginian. The specimen is damaged lacking parts of the upper and lower ends. It has a conserved length of 215 millimetres (8.5 in) and an estimated length of 240 millimetres (9.4 in). This genus is paleontologically significant for being the first ornithomimosaur specimen known from England and represents the earliest record of ornithomimosaurs.
Velocipes is a saurischian dinosaur genus from the Late Triassic that may have been a theropod; its fossils were found in the Norian-age Lissauer Breccia of southern Poland.
Fulgurotherium is a dubious genus of ornithischian dinosaur from the Late Cretaceous (Cenomanian) Griman Creek Formation. It lived in what is now Australia.
Magnosaurus was a genus of theropod dinosaur from the Middle Jurassic of England. It is based on fragmentary remains and has often been confused with or included in Megalosaurus.
Neosodon was a genus of sauropod dinosaur from the Late Tithonian-age Upper Jurassic Sables et Gres a Trigonia gibbosa of Pas-de-Calais department, France. It has never been formally given a species name, but is often seen as N. praecursor, which actually comes from a different animal. Often in the past, it had been assigned to the wastebasket taxon Pelorosaurus, but restudy has suggested that it could be related to Turiasaurus, a roughly contemporaneous giant Spanish sauropod. It is only known from six teeth.
Thecocoelurus is a dubious genus of theropod dinosaur from the early Cretaceous period of England. The phylogenetic placement of this genus is uncertain, and it has been referred to an oviraptosaur, an ornithomimosaur, or a therizinosaur by different researchers throughout its history.
Diplotomodon is a dubious genus of theropod dinosaur, from New Jersey. It was possibly a member of the Tyrannosauroidea, the clade that also contains Tyrannosaurus.
Variraptor is a genus of dromaeosaurid theropod dinosaur from the Late Cretaceous of France.
Heptasteornis is the name given to a potentially dubious genus of alvarezsaurid dinosaur from the Late Cretaceous. The type species is Heptasteornis andrewsi, described as a presumed gigantic prehistoric owl in 1975. It was previously included in Elopteryx nopcsai and indeed the holotypes of both were believed to be from the same individual as they were discovered, and initially were assigned the same specimen number. This appears to be in error however.
Erectopus is an extinct genus of basal allosauroid theropod from the Early Cretaceous La Penthiève Beds Formation of France and also possibly the Cernavodă Formation of southern Romania. The type species is E. superbus, which was initially known as a species of Megalosaurus.
This timeline of ceratosaur research is a chronological listing of events in the history of paleontology focused on the ceratosaurs, a group of relatively primitive, often horned, predatory theropod dinosaurs that became the apex predators of the southern hemisphere during the Late Cretaceous. The nature and taxonomic composition of the Ceratosauria has been controversial since the group was first distinguished in the late 19th century. In 1884 Othniel Charles Marsh described the new genus and species Ceratosaurus nasicornis from the Late Jurassic Morrison Formation of the western United States. He felt that it belonged in a new family that he called the Ceratosauridae. He created the new taxon Ceratosauria to include both the Ceratosauridae and the ostrich-like ornithomimids. The idea of the Ceratosauria was soon contested, however. Later that same decade both Lydekker and Marsh's hated rival Edward Drinker Cope argued that the taxon was invalid.