Maleevus

Maleevus is a genus of herbivorous ankylosaurid dinosaur from the late Cretaceous, around 90 million years ago, of Mongolia.

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.

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.

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. 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. The type species remains Syrmosaurus disparoserratus, the combinatio nova is Maleevus disparoserratus. In 1991, George Olshevsky named the species as a Pinacosaurus disparoserratus. 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.

The preserved maxillae have length of about twelve centimetres. This indicates that Maleevus was a medium-sized ankylosaur.

Syrmosaurus disparoserratus was by Maleev placed in the Syrmosauridae. Today it is seen as a member of the Ankylosauridae.