In a recently published scientific paper describing a new species of armoured dinosaur from the Nemegt Formation, it was postulated that some Late Cretaceous ankylosaurs evolved a selective feeding habit in order to avoid competition from other herbivorous dinosaurs.

The ankylosaurs Tarchia teresae and the recently described Tarchia tumanovae had relatively narrow muzzles, compared to earlier ankylosaurids known from the Bayanshiree, Djadokhta and Baruungoyot Formations. Although these ankylosaurs were around five metres in length and perhaps weighed as much as two thousand kilograms, there were several much larger types of herbivorous dinosaur that co-existed with them.

A diagram showing the major, large herbivores that have been scientifically described from the Upper Cretaceous Nemegt Formation of Mongolia. The relatively small size of the Tarchia spp. in comparison with the other large herbivorous dinosaurs may have led to selective pressure on these ankylosaurs to evolve a different feeding habit to reduce interspecific competition for food resources. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

Evolving a Selective Feeding Strategy to Avoid Excessive Competition

Writing in the academic journal “Scientific Reports”, the researchers postulate that Tarchia species became more selective feeders as a result of competition from other larger herbivorous dinosaurs such as titanosaurs, therizinosaurs and ornithomimosaurs such as the giant Deinocheirus (D. mirificus).

The shift in feeding strategy may have coincided with the arrival of more bulk feeders such as saurolophine hadrosaurids, that may have entered Asia from North America. The invasion of new, highly efficient, bulk-feeding hadrosaurs, may have caused even greater interspecific competition for limited resources, possibly driving selection pressure on the diets of ankylosaurs.

To read Everything Dinosaur’s earlier article on the scientific description of Tarchia tumanovae: Tarchia tumanovae a New Ankylosaur Species.

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