Betasuchus
Encyclopedia
Betasuchus was a theropod dinosaur
which lived during the Late Cretaceous
Period.
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, 66-65 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 mosasaur
s — to M. bredai.
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 19th and early 20th 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] 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).
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 abelisaur
id, 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 Abelisaur
oidea.
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.
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
which lived during the Late Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
Period.
Its fossil, holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
BMNH 42997 (now NHM R 42997), a part of a right femur
Femur
The femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...
, 312 mm long, was found in The Netherlands near Maastricht
Maastricht
Maastricht is situated on both sides of the Meuse river in the south-eastern part of the Netherlands, on the Belgian border and near the German border...
, and originally described as a new species of Megalosaurus
Megalosaurus
Megalosaurus is a genus of large meat-eating theropod dinosaurs of the Middle Jurassic period of Europe...
in 1883 by Harry Seeley
Harry Seeley
Harry Govier Seeley was a British paleontologist.-Career:Seeley was born in London, the son of Richard Hovill Seeley, goldsmith, and his second wife Mary Govier. He attended classes at the Royal School of Mines, Kensington before becoming an assistant to Adam Sedgwick at the Woodwardian Museum,...
: M. bredai, honouring the late Dutch biologist and geologist Jacob Gijsbertus Samuël van Breda
Jacob Gijsbertus Samuël van Breda
Jacob Gijsbertus Samuël van Breda was a Dutch biologist and geologist.Jacob was the son of Jacob van Breda, a Dutch physician, physicist and politician, and Anna Elsenera van Campen. His mother died when he was two years old...
, a director of the Teylers Museum
Teylers Museum
Teyler's Museum , located in Haarlem, is the oldest museum in the Netherlands. The museum is in the former home of Pieter Teyler van der Hulst . He was a wealthy cloth merchant and Amsterdam banker of Scottish descent, who bequeathed his fortune for the advancement of religion, art and science...
, 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
Maastrichtian
The Maastrichtian is, in the ICS' geologic timescale, the latest age or upper stage of the Late Cretaceous epoch or Upper Cretaceous series, the Cretaceous period or system, and of the Mesozoic era or erathem. It spanned from 70.6 ± 0.6 Ma to 65.5 ± 0.3 Ma...
; however all dinosaurian material from the formation that could be dated, stems from the latest Maastrichtian, 66-65 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 mosasaur
Mosasaur
Mosasaurs are large extinct marine lizards. The first fossil remains were discovered in a limestone quarry at Maastricht on the Meuse in 1764...
s — to M. bredai.
Friedrich von Huene
Friedrich von Huene was a German paleontologist who named more dinosaurs in the early 20th century than anyone else in Europe.-Biography:...
in 1926, however, showed that it came from a genus distinct from Megalosaurus — which in the 19th and early 20th century was a "wastebin" taxon where many unrelated carnivorous dinosaurs were lumped together. Von Huene thought that the fossil actually belonged to an ornithomimosaur
Ornithomimosauria
The Ornithomimosauria, ornithomimosaurs or ostrich dinosaurs were theropod dinosaurs which bore a superficial resemblance to modern ostriches. They were fast, omnivorous or herbivorous dinosaurs from the Cretaceous Period of Laurasia...
, and gave it the provisional designation "Ornithomimidorum [sic] genus b" (in Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
: 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).
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
Dale Russell
Dale A. Russell is a Canadian geologist/palaeontologist, currently Research Professor at The Department of Marine Earth and Atmospheric Sciences of North Carolina State University...
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
David B. Norman
David Bruce Norman is a British paleontologist, currently Director of the Sedgwick Museum, Cambridge University. He is a fellow at Christ's College, Cambridge where he teaches geology in the Natural Sciences tripos. He is a member of the Palaeontological Association. He has studied Iguanodon...
in 1990 listed Megalosaurus bredai as a nomen dubium
Nomen dubium
In zoological nomenclature, a nomen dubium is a scientific name that is of unknown or doubtful application...
.
Jean le Loeuff and Eric Buffetaut in 1991 concluded it was a small abelisaur
Abelisaur
Abelisaurs were a group of ceratosaurian dinosaurs which lived in the Southern hemisphere during the Cretaceous period. Some well-known dinosaurs of this group include Abelisaurus, Carnotaurus, and Majungasaurus. They are known for their small arms...
id, close to Tarascosaurus
Tarascosaurus
Tarascosaurus is a genus of, perhaps abelisaurid, theropod dinosaur from Late Cretaceous of France.After having in 1988 identified an upper jaw bone found near Pourcieux as belonging to a member of the Abelisauridae, French paleontologist Eric Buffetaut reviewed the known remains of larger...
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
Carnotaurus
Carnotaurus was a large predatory dinosaur. Only one species, Carnotaurus sastrei has been described so far.Carnotaurus lived in Patagonia, Argentina during the Campanian or Maastrichtian stage of the Late Cretaceous...
. 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
Dryptosaurus
Dryptosaurus was a genus of primitive tyrannosaur that lived in Eastern North America during the middle Maastrichtian stage of the Late Cretaceous period. Although largely unknown now outside of academic circles, a famous painting of the genus by Charles R...
, a tyrannosauroid
Tyrannosauroidea
Tyrannosauroidea is a superfamily of coelurosaurian theropod dinosaurs that includes the family Tyrannosauridae as well as more basal relatives. Tyrannosauroids lived on the Laurasian supercontinent beginning in the Jurassic Period...
. In 2004 Tykoski and Rowe placed Tarascosaurus within the Abelisaur
Abelisaur
Abelisaurs were a group of ceratosaurian dinosaurs which lived in the Southern hemisphere during the Cretaceous period. Some well-known dinosaurs of this group include Abelisaurus, Carnotaurus, and Majungasaurus. They are known for their small arms...
oidea.
Betasuchus is, besides Orthomerus
Orthomerus
Orthomerus is a genus of duckbill dinosaur from the Late Cretaceous of The Netherlands, Belgium and possibly Ukraine. It is today an obscure genus, but in the past was conflated with the much better known Telmatosaurus....
, the only dinosaur genus named from remains found in The Netherlands and the only non-avian theropod found in the Maastrichtian Beds.