''Malawisaurus'' (meaning "

Malawi Malawi (; or aláwi Tumbuka: ''Malaŵi''), officially the Republic of Malawi, is a landlocked country in Southeastern Africa that was formerly known as Nyasaland. It is bordered by Zambia to the west, Tanzania to the north and northeast ...

lizard") is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

titanosaurian Titanosaurs (or titanosaurians; members of the group Titanosauria) 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 thr ...

sauropod Sauropoda (), whose members are known as sauropods (; from '' sauro-'' + '' -pod'', 'lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their bo ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

. It is known from the

Dinosaur Beds 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 crocodyliomorphs remain ...

of northern Malawi, which probably date to the

Aptian The Aptian is an age in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous Epoch or Series and encompasses the time from 121.4 ± 1.0 Ma to 113.0 ± 1.0 Ma (million years ago), a ...

stage of the

Early Cretaceous The Early Cretaceous ( geochronological name) or the Lower Cretaceous (chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145 Ma to 100.5 Ma. Geology Pro ...

. The type species is ''M. dixeyi'' and the specific name honours Frederick Augustus Dixey.

Discovery and naming

''Malawisaurus dixeyi'' was originally described in 1928 by

Sidney H. Haughton Sidney Henry Haughton FRS (7 May 1888 – 24 May 1982) was an English-born South African paleontologist and geologist best known for his description of the sauropodomorph dinosaur '' Melanorosaurus'' in 1924, and his work on the geology of ...

as a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of ''

Gigantosaurus ''Gigantosaurus'' () is a dubious genus of sauropod dinosaur from the Late Jurassic Kimmeridge Clay Formation of England. The type species, ''Gigantosaurus megalonyx'', was named and described by Harry Govier Seeley in 1869. Its syntype series ...

'' (an invalid name for the diplodocid currently known as ''

Tornieria ''Tornieria'' ("for Tornier") is a genus of diplodocid sauropod dinosaur from the Late Jurassic in Lindi Region of Tanzania. It has a convoluted taxonomic history. Discovery and naming In 1907, German paleontologist Eberhard Fraas who wa ...

''). Haughton considered it closely related to the species ''G. robustus'' (later the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

of ''

Janenschia ''Janenschia'' (named after Werner Janensch) is a large herbivorous sauropod dinosaur from the Late Jurassic Tendaguru Formation of Lindi Region, Tanzania around 155 million years ago. Discovery and naming ''Janenschia'' has had a convolut ...

''). The holotype was discovered in the "

" of Malawi (then known as the

Nyasaland Protectorate Nyasaland () was a British protectorate located in Africa that was established in 1907 when the former British Central Africa Protectorate changed its name. Between 1953 and 1963, Nyasaland was part of the Federation of Rhodesia and Nyasalan ...

), which are usually considered to be of

Barremian The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 129.4 ± 1.5 Ma (million years ago) and 121.4 ± 1.0 Ma). It is a subdivision of the Early Cretaceous Epoch (or Lower Cretaceous Series). It is preceded ...

age based on

K–Ar dating Potassium–argon dating, abbreviated K–Ar dating, is a radiometric dating method used in geochronology and archaeology. It is based on measurement of the product of the radioactive decay of an isotope of potassium (K) into argon (Ar). Potassium ...

, though they have also been suggested to be Late Cretaceous in age based on the vertebrate assemblage, and possibly also the

Lupata Group The Lupata Group is an Aptian geologic group in the Tete Province of Mozambique and the Northern Region of Malawi. The group contains the Dinosaur Beds, a fossiliferous unit in Malawi that has provided dinosaur remains.Weishampel, et al. (2004) ...

. 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. The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

is SAM 7405, a partial skeleton and its type locality is Mwakasyunguti. ''Malawisaurus'' is not known outside of

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

- however, an isolated

tooth A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tear ...

resembles those associated with ''Malawisaurus'' and was found in the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...

(

Cenomanian The Cenomanian is, in the ICS' geological timescale, the oldest or earliest age of the Late Cretaceous Epoch or the lowest stage of the Upper Cretaceous Series. An age is a unit of geochronology; it is a unit of time; the stage is a unit in the s ...

)-aged

Alcântara Formation The Alcântara Formation is a geological formation in northeastern Brazil whose strata date back to the Cenomanian of the Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is d ...

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

according to a report in 2007. It is currently listed as "Titanosauria indet., possibly ''Malawisaurus'' .sp".

Description

Relatively small by sauropod standards, ''Malawisaurus'' reached lengths of about , and weighed about . In 2020 it was given a smaller estimation of 11 meters (36 ft) and 2.8 tonnes (3.1 short tons). 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 Centra is a convenience shop chain that operates throughout Ireland. The chain operates as a symbol group owned by Musgrave Group, the food wholesaler, meaning the stores are all owned by individual franchisees. The chain has three different ...

. ''Malawisaurus'' had vertebral lateral fossae that resembled shallow depressions. Fossae that similarly resemble shallow depressions are known from ''

Saltasaurus ''Saltasaurus'' (which means "lizard from Salta") 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 ...

'', '' Alamosaurus'', ''

Aeolosaurus ''Aeolosaurus'' (; "Aeolus' lizard") 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. ''Aeolos ...

'', and ''

Gondwanatitan ''Gondwanatitan'' (meaning "giant from Gondwana") was a titanosaurian sauropod dinosaur. ''Gondwanatitan'' was found in Brazil, at the time part of the southern supercontinent Gondwana, in the late Cretaceous Period (70 mya). Like some other ...

''.

Classification

By definition, ''Malawisaurus'' has to be the most basal lithostrotian. The cladogram below follows Franca ''et al.'' (2016).

References

Footnotes

* S. H. Haughton. 1928. On some reptilian remains from the Dinosaur Beds of Nyasaland. Transactions of the Royal Society of South Africa 16:67-75 * Paul, Gregory S. (2010) ''The Princeton Field Guide to Dinosaurs''. * Tidwell, V., Carpenter, K. & Meyer, S. 2001. New Titanosauriform (Sauropoda) from the Poison Strip Member of the Cedar Mountain Formation (Lower Cretaceous), Utah. In: Mesozoic Vertebrate Life. D. H. Tanke & K. Carpenter (eds.). Indiana University Press, Eds. D.H. Tanke & K. Carpenter. Indiana University Press. 139-165.

External links

page on ''Malawisaurus'' from DinoDictionary.

New material of an Early Cretaceous titanosaurid dinosaur of Malawi

* ttps://web.archive.org/web/20110715174436/http://www.rescast.com/specimens/show_select_specimen.php?SpecimenID=48 Research Casting International - ''Malawisaurus dixeyi'' {{Taxonbar, from=Q133655 Lithostrotians Aptian life Early Cretaceous dinosaurs of Africa Cretaceous Malawi Fossils of Malawi Fossil taxa described in 1993 Taxa named by Louis L. Jacobs