Malawisaurus

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Malawisaurus
Temporal range: Early-Late Cretaceous,
Barremian–Cenomanian
PreꞒ
Ꞓ
O
S
D
C
P
T
J
K
Pg
N
August 1, 2012 - Malawisaurus on Display at the Royal Ontario Museum.jpg
Display at the Royal Ontario Museum
Scientific classification edit
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: †Sauropodomorpha
Clade: †Sauropoda
Clade: †Macronaria
Clade: †Titanosauria
Clade: †Eutitanosauria
Clade: †Lithostrotia
Genus: †Malawisaurus
Jacobs et al., 1993
Species:
†M. dixeyi
Binomial name
†Malawisaurus dixeyi
(Haughton, 1928) [originally Gigantosaurus, preoccupied]
Synonyms
  • Gigantosaurus dixeyi Haughton, 1928 (preoccupied)
  • Tornieria dixeyi (Haughton, 1928)
  • Janenschia dixeyi (Haughton, 1928)

Malawisaurus (meaning "Malawi lizard") was a genus of titanosaurian sauropod dinosaur. It lived in what is now Malawi and possibly Brazil,[1] during the Barremian-Cenomanian ages of the Early-Late Cretaceous. It is one of the few titanosaurs for which skull material has been found.

Discovery and naming[]

Size comparison

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). It was found in the "Dinosaur Beds" of Malawi, 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] and possibly also the Lupata Group. 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 .

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.[1]

Description[]

A reconstruction of the head

Relatively small by sauropod standards, Malawisaurus reached lengths of about 16 metres (52 ft), and weighed about 10 tonnes (11 short tons).[4] In 2020 it was given a smaller estimation of 11 meters (36 ft) and 2.8 tonnes (3.1 short tons).[5] 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.[6] Malawisaurus had vertebral lateral fossae that resembled shallow depressions.[7] Fossae that similarly resemble shallow depressions are known from Saltasaurus, Alamosaurus, Aeolosaurus, and Gondwanatitan.[7]

Classification[]

By definition, Malawisaurus has to be the most basal lithostrotian. The cladogram below follows Franca et al. (2016).[8]

Lithostrotia
 

Malawisaurus

 
 
 

Muyelensaurus

 
 
Nemegtosauridae
 

Nemegtosaurus

 
 
 

Tapuiasaurus

 
 

Rapetosaurus

 
 
 
Saltasauroidea
 

Diamantinasaurus

 
 

Baurutitan

 
 

Isisaurus

 
Saltasauridae
 
 

Alamosaurus

 
 

Opisthocoelicaudia

 
 
 
 

Neuquensaurus

 
 

Saltasaurus

 
 
 
Aeolosaurini
 

Maxakalisaurus

 
 

Panamericansaurus

 
 

Rinconsaurus

 
 
 

Gondwanatitan

 
 
 

Aeolosaurus maximus

 
 
 

Aeolosaurus colhuehuapensis

 
 

Aeolosaurus rionegrinus

 
 
 
 
 
 
 
 
 

See also[]

References[]

  1. ^ a b Freire, Pedro Carvalho; Medeiros, Manuel Alfredo; Lindoso, Rafael Matos (2007). "Sauropod teeth diversity in the Laje do Coringa fossiliferous site, Eocenomanian of Northeastern Brazil". Paleontologia: Cenários de Vida: 523–532.
  2. ^ Andrzejewski, Kate A.; Polcyn, Michael J.; Winkler, Dale A.; Chindebvu, Elizabeth Gomani; Jacobs, Louis L. (2019-02-13). "The braincase of Malawisaurus dixeyi (Sauropoda: Titanosauria): A 3D reconstruction of the brain endocast and inner ear". PLOS ONE. 14 (2): e0211423. doi:10.1371/journal.pone.0211423. ISSN 1932-6203. PMC 6373922. PMID 30759166.
  3. ^ L. L. Jacobs, D. A. Winkler, W. R. Downs and E. M. Gomani. 1993. New material of an Early Cretaceous titanosaurid sauropod dinosaur from Malawi. Palaeontology 36(3):523-534
  4. ^ Paul, G.S., 2010, The Princeton Field Guide to Dinosaurs, Princeton University Press p. 207
  5. ^ Molina-Pérez & Larramendi (2020). Dinosaur Facts and Figures: The Sauropods and Other Sauropodomorphs. New Jersey: Princeton University Press. p. 264.
  6. ^ "Caudal Vertebrae," Tidwell, Carpenter, and Meyer (2001). Page 145.
  7. ^ a b "Caudal Vertebrae," Tidwell, Carpenter, and Meyer (2001). Page 147.
  8. ^ França, M.A.G.; Marsola, J.C.d A.; Riff, D.; Hsiou, A.S.; Langer, M.C. (2016). "New lower jaw and teeth referred to Maxakalisaurus topai (Titanosauria: Aeolosaurini) and their implications for the phylogeny of titanosaurid sauropods". PeerJ. 4: e2054. doi:10.7717/peerj.2054. PMC 4906671. PMID 27330853.

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[]

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