Malawisaurus Temporal range: Early Cretaceous | |
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Display at the Royal Ontario Museum | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | Saurischia |
Clade: | † Sauropodomorpha |
Clade: | † Sauropoda |
Clade: | † Macronaria |
Clade: | † Titanosauria |
Clade: | † Lithostrotia |
Genus: | † Malawisaurus Jacobs et al., 1993 |
Species: | †M. dixeyi |
Binomial name | |
†Malawisaurus dixeyi (Haughton, 1928) [originally Gigantosaurus, preoccupied] | |
Synonyms | |
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Malawisaurus (meaning "Malawi lizard") is an extinct genus of titanosaurian sauropod dinosaur. It is known from the Dinosaur Beds of northern Malawi, which probably date to the Aptian stage of the Early Cretaceous. The type species is M. dixeyi and the specific name honours Frederick Augustus Dixey.
Malawisaurus dixeyi was originally described in 1928 by Sidney H. Haughton as a species of Gigantosaurus (an invalid name for the diplodocid currently known as Tornieria ). Haughton considered it closely related to the species G. robustus (later the type species of Janenschia ). The holotype was discovered c. 1924 in the "Dinosaur Beds" of Malawi (then known as the Nyasaland Protectorate), [1] which are usually considered to be of Barremian-Aptian age based on K–Ar dating, though they have also been suggested to be Late Cretaceous in age based on the vertebrate assemblage. [2] In 1993 it was placed in the newly named genus Malawisaurus by Louis L. Jacobs and colleagues, based on newly collected material from the locality. [3] The holotype is SAM 7405, a partial skeleton and its type locality is Mwakasyunguti.
Malawisaurus is not known outside of Africa - however, an isolated tooth resembles those associated with Malawisaurus and was found in the Late Cretaceous (Cenomanian)-aged Alcântara Formation of Brazil according to a report in 2007.It is currently listed as "Titanosauria indet., possibly Malawisaurus .sp". [4]
Relatively small by sauropod standards, Malawisaurus reached lengths of about 15 metres (49 ft), and weighed about 10 tonnes (11 short tons). [5] In 2020 it was given a smaller estimation of 11 meters (36 ft) and 2.8 tonnes (3.1 short tons). [6] Like some other titanosaurs, ossicles have been found which are believed to represent dermal scutes that covered the skin.
The vertebrae from the middle part of its tail had elongated centra. [7] Malawisaurus had vertebral lateral fossae that resembled shallow depressions. [8] Fossae that similarly resemble shallow depressions are known from Saltasaurus , Alamosaurus , Aeolosaurus , and Gondwanatitan . [8]
By definition, Malawisaurus has to be the most basal lithostrotian. The cladogram below follows Franca et al. (2016). [9]
Lithostrotia |
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Saltasaurus is a genus of saltasaurid dinosaur of the Late Cretaceous period of Argentina. Small among sauropods, though still heavy by the standards of modern creatures, Saltasaurus was characterized by a short neck and stubby limbs. It was the first genus of sauropod known to possess armour of bony plates embedded in its skin. Such small bony plates, called osteoderms, have since been found on other titanosaurians.
Titanosaurs were a diverse group of sauropod dinosaurs, including genera from all seven continents. The titanosaurs were the last surviving group of long-necked sauropods, with taxa still thriving at the time of the extinction event at the end of the Cretaceous. This group includes some of the largest land animals known to have ever existed, such as Patagotitan—estimated at 37 m (121 ft) long with a weight of 69 tonnes —and the comparably-sized Argentinosaurus and Puertasaurus from the same region.
Alamosaurus is a genus of titanosaurian sauropod dinosaurs containing a single known species, Alamosaurus sanjuanensis, from the Maastrichtian age of the Late Cretaceous period in what is now southwestern North America. It is the only known titanosaur to have inhabited North America after the nearly 30-million year absence of sauropods from the North American fossil record and probably represents an immigrant from South America.
Aeolosaurus is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous Period of what is now South America. Like most sauropods, it would have been a quadrupedal herbivore with a long neck and tail. Aeolosaurus is well known for a titanosaur, as it is represented by the remains of several individuals belonging to at least two species. However, like most titanosaurs, no remains of the skull are known. The holotype of Aeolosaurus rionegrinus consists of a series of seven tail vertebrae, as well as parts of both forelimbs and the right hindlimb. It was discovered in the Angostura Colorada Formation in Argentina, which dates from the Campanian stage of the Late Cretaceous, about 83 to 74 million years ago. The species A. maximus was transferred over to the new genus Arrudatitan in 2021.
Bonitasaura is a genus of titanosaurian dinosaur hailing from uppermost layers of the Late Cretaceous (Santonian) Bajo de la Carpa Formation, Neuquén Group of the eastern Neuquén Basin, located in Río Negro Province, Northwestern Patagonia, Argentina. The remains, consisting of a partial sub-adult skeleton jumbled in a small area of fluvial sandstone, including a lower jaw with teeth, a partial vertebrae series, and limb bones, were described by Sebastian Apesteguía in 2004.
Gondwanatitan was a titanosaurian sauropod dinosaur. Gondwanatitan was found in Brazil, at the time part of the southern supercontinent Gondwana, in the late Cretaceous Period. Like some other sauropods, Gondwanatitan was tall and ate tough shoots and leaves off of the tops of trees. G. faustoi's closest relative was Aeolosaurus.
Adamantisaurus is a poorly-known genus of titanosaurian sauropod dinosaur from the Late Cretaceous Period of what is now South America. It is only known from six tail vertebrae but, as a sauropod, it can be assumed that this dinosaur was a very large animal with a long neck and tail.
Andesaurus is a genus of basal titanosaurian sauropod dinosaur which existed during the middle of the Cretaceous Period in South America. Like most sauropods, belonging to one of the largest animals ever to walk the Earth, it would have had a small head on the end of a long neck and an equally long tail.
Cedarosaurus was a nasal-crested macronarian dinosaur genus from the Early Cretaceous Period (Valanginian). It was a sauropod which lived in what is now Utah. The fossils were discovered in 1996 in eastern Utah within the rocks of the Yellow Cat Member of the Cedar Mountain Formation. It was officially named and described by Tidwell, Carpenter and Brooks in 1999.
Laplatasaurus is a genus of titanosaurian sauropod dinosaur that lived during the Late Cretaceous in South America, with the holotype and only known specimen found in the Anacleto Formation.
Venenosaurus is a genus of sauropod dinosaur that lived in what is now Utah during the Early Cretaceous. Its type and only species is Venenosaurus dicrocei. Fossils of Venenosaurus were first discovered in 1998, by Denver Museum of Natural History volunteer Anthony DiCroce, and described as a new genus and species in 2001 by Virginia Tidwell and colleagues, who named the species for DiCroce. Venenosaurus was a relatively small sauropod, and was similar to Cedarosaurus, another sauropod from the Early Cretaceous of Utah.
Chubutisaurus is a genus of somphospondylan sauropod dinosaur from the Early Cretaceous Cerro Barcino Formation (Albian) of Argentina. The type species, Chubutisaurus insignis, was described by del Corro in 1975. Chubutisaurus had a more robust radius than Venenosaurus. In 2010 Gregory Paul gave a length of 18 meters (59 ft) and a weight of 12 tonnes. Thomas Holtz estimated its length at 23 meters (75.5 ft) in 2012.
Karongasaurus is a genus of titanosaur sauropod dinosaur from the Early Cretaceous. The type species, K. gittelmani, was described by Elizabeth Gomani in 2005.
Rinconsaurus is a genus of titanosaur sauropod dinosaur from the Late Cretaceous in what is now Argentina. The type species, Rinconsaurus caudamirus, was described by Calvo and Riga in 2003, and is based on three partial skeletons.
Puertasaurus is a genus of sauropod dinosaur that lived in South America during the Late Cretaceous Period. It is known from a single specimen recovered from sedimentary rocks of the Cerro Fortaleza Formation in southwestern Patagonia, Argentina, which probably is Campanian or Maastrichtian in age. The only species is Puertasaurus reuili. Described by the paleontologist Fernando Novas and colleagues in 2005, it was named in honor of Pablo Puerta and Santiago Reuil, who discovered and prepared the specimen. It consists of four well-preserved vertebrae, including one cervical, one dorsal, and two caudal vertebrae. Puertasaurus is a member of Titanosauria, the dominant group of sauropods during the Cretaceous.
Amargatitanis is a genus of dicraeosaurid sauropod dinosaur from the Barremian-age La Amarga Formation of Neuquén, Argentina. It is known from a single, incomplete postcranial skeleton consisting of a partial hindlimb, ischium, and two vertebrae. These remains were unearthed by Argentine paleontologist José Bonaparte in 1983 during an expedition by the Museo Argentino de Ciencias Naturales and later described as a new genus and species, Amargatitanis macni by Sebastián Apesteguía. The genus name comes from the words Amarga, where the fossils were collected, and titanis meaning "titan". Its species name is in reference to the MACN, where the remains are stored.
Lithostrotia is a clade of derived titanosaur sauropods that lived during the Early Cretaceous and Late Cretaceous. The group was defined by Upchurch et al. in 2004 as the most recent common ancestor of Malawisaurus and Saltasaurus and all the descendants of that ancestor. Lithostrotia is derived from the Ancient Greek lithostros, meaning "inlaid with stones", referring to the fact that many known lithostrotians are preserved with osteoderms. However, osteoderms are not a distinguishing feature of the group, as the two noted by Unchurch et al. include caudal vertebrae with strongly concave front faces (procoely), although the farthest vertebrae are not procoelous.
The Dinosaur Beds is a geological formation in Malawi whose strata date back to the Early Cretaceous. The age of the deposit is poorly constrained, but is likely to date from the Barremian to Aptian. Dinosaurs, turtles and crocodylomorphs remains are among the fossils that have been recovered from the formation. It is correlated with the Galula Formation in Tanzania. It consists of two members, a lower unfossiliferous member consisting of deep red stained sandstones, and an upper fossiliferous member consisting of white sands and grey to red mudstones and siltstones. The upper member is 210 m thick in the vicinity of the CD-9 locality.
Aeolosaurini is an extinct clade of titanosaurian dinosaurs known from the Cretaceous period of Argentina and Brazil. Rodrigo M. Santucci and Antonio C. de Arruda-Campos (2011) in their cladistic analysis found Aeolosaurus, Gondwanatitan, Maxakalisaurus, Panamericansaurus and Rinconsaurus to be aeolosaurids.
Katepensaurus is an extinct genus of rebbachisaurid sauropod dinosaur known from the Late Cretaceous of south-central Chubut Province of central Patagonia, Argentina. It contains a single species, Katepensaurus goicoecheai.