A new genus and species of theropod dinosaur with a streamlined body as in diving birds has been identified from a well-preserved skeleton found in Mongolia.
Life reconstruction of Natovenator polydontus. Image credit: Yusik Choi.
The newly-identified dinosaur species lived in Mongolia during the Late Cretaceous epoch, some 71 million years ago.
Named Natovenator polydontus, the ancient creature had a streamlined body similar to those of modern diving birds and a long neck similar to modern water birds such as geese.
“Streamlining a body is a major adaptation for aquatic animals to move efficiently in the water,” said Seoul National University paleontologist Yuong-Nam Lee and colleagues.
“Whereas diving birds are well known to have streamlined bodies, such body shapes have not been documented in non-avian dinosaurs.”
“Natovenator polydontus was a capable swimmer, providing the first compelling evidence of a streamlined body in a non-avian theropod dinosaur.”
The fossilized remains of Natovenator polydontus were recovered from the Baruungoyot Formation at Hermiin Tsav in the southern Mongolian Gobi Desert.
The specimen is a mostly complete skeleton and features the skull, spinal column, one forelimb, and the remains of two hindlimbs.
An analysis of the evolutionary relationships between Natovenator polydontus and other theropod dinosaurs indicate that it was closely related to halszkaraptorines, a group of non-avian theropods that previous research has suggested may have been adapted for a semiaquatic lifestyle.
“Ever since land vertebrates emerged, many different groups have secondarily adapted to aquatic environments,” the paleontologists said.
“Dinosaurs have been peculiar in this regard because only avian dinosaurs are known for various aquatic forms, including extinct clades.”
“The body plan of Natovenator polydontus makes it clear that some non-avian dinosaurs returned to the water.”
The discovery of Natovenator polydontus is reported in a paper in the journal Communications Biology.
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S. Lee et al. 2022. A non-avian dinosaur with a streamlined body exhibits potential adaptations for swimming. Commun Biol 5, 1185; doi: 10.1038/s42003-022-04119-9
