Posts Tagged ‘spinosaurid’
Name: »East-African lizard«
Length: 8 m
Height: 2 m
Weight: 2 tons
Time: Jurassic (148-145,5 MYA)
Location: Africa (Tanzania)
Ostafrikasaurus is a genus of spinosaurid theropod dinosaurs known from the Jurassic of Tendaguru, southeastern Tanzania. It contains a single species, Ostafrikasaurus crassiserratus.
Ostafrikasaurus is only known from the holotype specimen MB R 1084, an isolated tooth. It was originally referred to Labrosaurus? stechowi by Werner Janensch in 1920. All teeth assigned to L.? stechowi were collected by German expeditions from 1909 to 1913 from the area around Tendaguru hill in southeastern Tanzania, German East Africa. Janensch (1925) described a total of nine teeth, which he assigned to L.? stechowi (holotype MB R 1083) and divided them into five types. Later the teeth were reassigned to ?Ceratosaurus stechowi, as Labrosaurus found to be a junior synonym of Allosaurus. Recent studies usually suggest that Labrosaurus stechowi is a nomen dubium, and that these teeth are indeterminate, perhaps representing different taxa.
MB R 1084, which is the only teeth from the Upper Dinosaur Member (Obere Dinosauriermergel) of the Tendaguru Formation, differs in several respects from the other teeth, from the Middle Dinosaur Member (Mittlere Dinosauriermergel). Although Buffetaut in 2008 suggested that another isolated tooth, MB R 1091 collected from the Middle Dinosaur Member, may also represent the same genus as MB R 1084, Buffetaut when naming Ostafrikasaurus in 2012 did not refer it to the genus. The Upper Dinosaur Member of the Tendaguru Formation dates back to the middle and late Tithonian faunal stage of the Late Jurassic, about 148-145.5 million years ago.
Ostafrikasaurus is based on a thick and serrated tooth which is about 49 mm (1.9 in) in length. Buffetaut (2008) suggested that this tooth represents a new genus of Spinosauridae, and that it differs from other teeth previously referred to L.? stechowi. Oliver Rauhut (2011) listed some of these differences: MB R 1084 has a much higher number of lingual ridges (up to eleven) and presents three ridges and grooves on the labial side. Furthermore, some of the lingual ridges extend over almost the entire length of the crown, leaving only the apicalmost 5 mm of the crown smooth, whereas others are restricted to the basal part, being intercalated with ridges that extend further apically. Additionally, ridges are present over almost the entire mesial (front) threefifths of the crown, whereas the distal (back) two-fifths are devoid of any ornamentation. Mesially, the ridged area is slightly set off from the mesial carina by a slightly mesiodistally concave area. However, its general shape and serration density is very similar to the teeth from the Middle Dinosaur Member, as all teeth have 10 denticles per 5 mm distally and 13 denticles per 5 mm mesially. Finally, Rauhut suggested that it is possible that this tooth represents the same taxon as the other teeth, or a closely related taxon.
Buffetaut in 2012 assigned Ostafrikasaurus to the Spinosauridae, based on the fact that the tooth displays an enamel ornamentation that resembles many baryonychines including Baryonyx, but differs from all other known spinosaurids by the large size of the denticles borne by the carinae. Thus, Ostafrikasaurus, according to Buffetaut, represents the earliest currently known spinosaurid. The tooth suggests that the dental evolution of spinosaurids have been characterised by reduction of the denticles.
Ostafrikasaurus was first described and named by Eric Buffetaut in 2012 and the type species is Ostafrikasaurus crassiserratus. The generic name is derived from Deutsch-Ostafrika (or German East Africa, a German colony in East Africa, which included what are now Burundi, Rwanda and Tanganyika) in which the holotype was found, from the Greek σαῦρος, sauros meaning “lizard”. The specific name is derived from the Latin crassus, meaning “thick” and serratus, “serrated” in reference to the shape of the holotype tooth.
Genus: Ostafrikasaurus Buffetaut, 2012
Species: O. crassiserratus
Binomial name: Ostafrikasaurus crassiserratus Buffetaut, 2012
Name: »fish hunter«
Length: 9 m
Height: 2,5 m
Weight: 3 tons
Diet: carnivore (piscivore)
Location: Asia (Laos)
Ichthyovenator is a spinosaurid theropod dinosaur from the Early Cretaceous of Laos. Ichthyovenator is known from a single type species, Ichthyovenator laosensis. The species was named and described in 2012 by Ronan Allain, Tiengkham Xeisanavong, Philippe Richir and Bounsou Khentavong. The generic name is derived from Greek ἰχθύς (ichthys), “fish”, and Latin venator, “hunter”, in reference to a piscivorous lifestyle. The specific name refers to the provenance from Laos.
Ichthyovenator is represented by a single holotype or syntype series MDS BK10-01 — 15. The skeleton was found in the Grès supérieurs Formation of the Savannakhet Basin in Savannakhet Province, in a layer which is likely Aptian in age, about 115 million years old. It consists of a partial skeleton lacking the skull. It includes the penultimate dorsal vertebra, the spine of the last dorsal vertebra, five sacral vertebrae, the first two caudal vertebrae, both ilia, both ischia, a right pubis and a posterior rib.
Unlike other spinosaurids, Ichthyovenator has at least two separate sails. The preserved axial column, over a metre long, shows a very high spine on the penultimate back vertebra, representing a crest extending from the back, and a lower rounded sail extending from the sacral vertebrae of the hip, with its highest point above the third and fourth sacrals.
Ichthyovenator was by its describers assigned to the Spinosauridae and more precisely to the Baryonychinae, as the sister species of a clade formed by Baryonyx and Suchomimus. In 2012, the excavations at the site were not yet completed and there is hope for further discoveries. The specimens are part of the collection of the dinosaur museum in Savannakhet, Laos.
Spinosaurids are among the largest and most specialized carnivorous dinosaurs. The morphology of their crocodile-like skull, stomach contents, and oxygen isotopic composition of the bones suggest they had a predominantly piscivorous diet. Even if close relationships
between spinosaurids and Middle Jurassic megalosaurs seem well established, very little is known about the transition from a generalized large basal tetanuran to the specialized morphology of spinosaurids. Spinosaurid remains were previously known from the Early to Late Cretaceous of North Africa, Europe, and South America. Here, we report the discovery of a new spinosaurid theropod from the late Early Cretaceous Savannakhet Basin in Laos, which is distinguished by an autapomorphic sinusoidal dorsosacral sail. This new taxon, Ichthyovenator laosensis gen. et sp. nov., includes well-preserved and partially articulated postcranial remains. Although possible spinosaurid teeth have been reported from various Early Cretaceous localities in Asia, the new taxon I. laosensis is the first definite record of Spinosauridae from Asia. Cladistic analysis identifies Ichthyovenator as a member of the sub-clade Baryonychinae and suggests a widespread distribution of this clade at the end of the Early Cretaceous. Chilantaisaurus tashouikensis from the Cretaceous of Inner Mongolia, and an ungual phalanx from the Upper Jurassic of Colorado are also referred to spinosaurids, extending both the stratigraphical and geographical range of this clade.
Genus: Ichthyovenator Allain
Type species: Ichthyovenator laosensis Allain
Name: »crocodile lizard«
Length: 9 m
Height: 3 m
Weight: 3 tons
Time: Cretaceous (100 MYA)
Location: Europe (England)
Suchosaurus (meaning “crocodile lizard”) is as a spinosaurid theropod dinosaur from Cretaceous England, originally believed to be a genus of crocodile. The type material consists of teeth. Two species, S. cultridens and S. girardi have been named, though the S. girardi material was reclassified by Buffetaut as Baryonyx walkeri. The remaining species, S. cultridens, is known only from a single tooth that strongly resembles the teeth of the contemporary Baryonyx walkeri. While there are some differences between the teeth, these may or may not represent individual variation among specimens, and Suchosaurus may be a senior synonym of Baryonyx.
Suchosaurus was considered a nomen dubium by Mateus et al. (2011).
Genus: Suchosaurus Owen, 1841
Species: S. cultridens Owen, 1841
Synonyms: Baryonyx Charig & Milner, 1986
Name: »chinese other lizard«
Time: Cretaceous (110-100 MYA)
Location: Asia (China)
“Sinopliosaurus” is a spinosaurid theropod dinosaur from the Early Cretaceous of southern China, known only from teeth. It includes a single species, “S.” fusuiensis, that was first assigned to the plesiosaur Sinopliosaurus. Because this species is not a plesiosaur and therefore is not within the genus Sinopliosaurus, the name “Sinopliosaurus” is used in quotation marks. The teeth came from an animal similar to Siamosaurus.
Species: “Sinopliosaurus” fusuiensis
Name: »crested lizard«
Length: 8 – 10 m
Height: 5 m
Weight: 2,5 – 3,5 tons
Time: Cretaceous (120-110 MYA)
Location: Africa (Niger)
Cristatusaurus (meaning “Crested reptile”) is an extinct genus of spinosaurid theropod dinosaur. It lived during the Early Cretaceous Period of what is now Africa.
Its fossils were found at Gadoufaoua in Niger, Africa, in 1973. These fossils are quite similar to those of Baryonyx and Suchomimus. The type species, C. lapparenti, was formally described by Taquet and Russell, in 1998.
There is some debate over the identity of this creature, in that some argue that it may be the same dinosaur as Suchomimus, which has also been found in Niger. Some therefore suggest that Cristatusaurus is a dubious name.
Some theropod specialist think the anatomical differences between the material of Suchomimus tenerensis (Sereno et al. 1998) and Baryonyx walkeri only warrant recognition of the former as a distinct species of Bayonyx, [Baryonyx tenerensis] and that the generic names “Cristatusaurus and Suchomimus should be considered subjective junior synonyms of Baryonyx.
Species: C. lapparenti
Binomial name: Cristatusaurus lapparenti Taquet and Russell, 1998
A relative of a giant fish-eating dinosaur that dwarfed T. rex once roamed Australia, say researchers, providing growing evidence for the worldwide distribution of many dinosaur branches.
They add the find provides “weak” evidence to support the theory that Africa was the first of the continents to split from Gondwanaland.
Co-author, Thomas Rich of Museum Victoria, says the claims, published in Biology Letters, are based on a four-centimeter (1.6-inch) neck vertebra found by Michael Cleeland and George Caspar at Dinosaur Cove near Cape Otway, Victoria.
Read the rest of this entry »
Name: »Oxala (high god)«
Length: 12-14 m
Height: 5 m
Weight: 5-7 tons
Time: Cretaceous (98-95 MYA)
Location: South America (Brasil)
Oxalaia is a genus of carnivorous theropod. It is a spinosaurid which lived during the late Cretaceous (Cenomanian stage, about 98 million years ago) in what is now Brazil. It is known from the holotype MN 6117-V, a partial skull (Premaxilla) and some referred teeth, which were found in the AlcÃ¢ntara Formation (Laje do Coringa locality) on Cajual Island, Maranhao State of Northeastern Brazil. The fossil was found in 1999 on the Ilha do Cajual near Maranhao and were recovered in 2004. It was named by Alexander Kellner, Sergio Azevedeo, Elaine Machado, Luciana Carvalho and Deise Henriques in 2011 and the type species is Oxalaia quilombensis. Estimates suggest that it was 12 to 14 metres (39 to 46 ft) in length, weighted five to seven tons and it is the largest theropod known from Brazil and the seventh officially named species of theropod from Brazil.
The genus name refers to Oxala, the highest god in the Yorubareligie. The specific name refers to the Portuguese word quilombo, which designates a community of runaway slaves who once inhabited Cajual. The connection with Africa refers also to the hypothesis that the discovery area a period in the Cretaceous or with the African continent.
The holotype was found in layers dating from the Cenomanien, about 98-95 million years old. It consists of two pieces of the skull: the front of the muzzle point praemaxilla member, and a more rearward fragment of the upper branch of the maxilla. It is part of the collection of the Museu Nacional da Universidade Federal do Rio de Janeiro.
Species: O. quilombensis Kellner et al., 2011