Maleevus

Maleevus (named in honour of Evgeny Maleev) is an extinct genus of herbivorous ankylosaurid dinosaur from the late Cretaceous, around 90 million years ago (possibly 98-83 Ma), of Mongolia.[1]

Maleevus
Temporal range: Late Cretaceous 90 Ma
Scientific classification
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Maleevus

Tumanova, 1987
Binomial name
Maleevus disparoserratus
Tumanova, 1987
Synonyms
  • Syrmosaurus disparoserratus Maleev 1952

Discovery and namingEdit

Between 1946 and 1949, Soviet-Mongolian expeditions uncovered fossils at Shiregin Gashun. In 1952, Soviet palaeontologist Evgenii Aleksandrovich Maleev named some ankylosaurian bone fragments as a new species of Syrmosaurus: Syrmosaurus disparoserratus. The specific name refers to the unequal serrations on the teeth.[1]

The holotype, PIN 554/I, was found in a layer of the Bayan Shireh Formation dating from the Cenomanian-Santonian. It consists of two upper jawbones, left and right maxillae. Maleev erroneously assumed these represented the lower jaws. Referred was specimen PIN 554/2-1, the rear of the skull of another individual.[1]

In 1977, Teresa Maryańska noted a similarity with another Mongolian ankylosaur, Talarurus, in that both taxa have separate openings for the ninth to twelfth cerebral nerve; she therefore renamed the species as Talarurus disparoserratus.[2] Having determined that Syrmosaurus is a junior synonym of Pinacosaurus, Soviet palaeontologist Tatyana Tumanova named the material as a new genus Maleevus in honor of Maleev in 1987.[3] The type species remains Syrmosaurus disparoserratus, the combinatio nova is Maleevus disparoserratus.[4] In 1991, George Olshevsky named the species as a Pinacosaurus disparoserratus.[5] In 2014, Victoria Megan Arbour determined that the rear skull was not different from that of many other ankylosaurids and that the single distinguishing trait of the teeth, a zigzag pattern on the cingulum, was shared with Pinacosaurus. She concluded that Maleevus was a nomen dubium.[6]

SizeEdit

The preserved maxillae have length of about twelve centimetres.[1] This indicates that Maleevus was a medium-sized ankylosaur of around 6 metres (20 ft). The height and weight of Maleevus is unknown due to the lack of known remains. (size estimates based on the related Talarurus).

ClassificationEdit

Syrmosaurus disparoserratus was by Maleev placed in the Syrmosauridae.[1] Today Maleevus is seen as a member of the Ankylosauridae.

See alsoEdit

ReferencesEdit

  1. ^ a b c d e Maleev E.A., 1952, "Новый анқилосавр из вернего мела Монголии", Doklady Akademii Nauk, SSSR 87: 273-276
  2. ^ T. Maryańska, 1977, "Ankylosauridae (Dinosauria) from Mongolia", Palaeontologia Polonica 37: 85-151
  3. ^ The armored dinosaurs of Mongolia [in Russian], Tumanova - 1987.
  4. ^ T.A. Tumanova, 1987, "Pantsirnyye dinozavry Mongolii", Trudy Sovmestnaya Sovetsko-Mongol'skaya Paleontologicheskaya Ekspeditsiya 32: 1-80
  5. ^ Olshevsky, G., 1991, A revision of the parainfraclass Archosauria Cope, 1869, excluding the advanced Crocodylia. Mesozoic Meanderings 2, 196 pp
  6. ^ Arbour, Victoria Megan, 2014, Systematics, evolution, and biogeography of the ankylosaurid dinosaurs. Ph.D thesis, University of Alberta