[D] Haya griva [Su] [sG] [T]
Makovicky, Kilbourne, Sadleir & Norell 2011
Cretaceous Late Santonian
Javkhlant Formation, Khugenetslavkant locality, Mongolia
Basal ornithopods exhibit a very low diversity in Cretaceous deposits of Asia, with only two diagnostic taxa published to date. A new basal ornithopod, Haya griva, gen. et sp. nov., is described here based on several well-preserved specimens from the Late Cretaceous Javkhlant Formation of Mongolia. Haya is diagnosed by a unique combination of characters, some of which are also present in other Asian Cretaceous basal ornithopods such as a bifid caudal ramus of the jugal and a tapering and beveled predentary.
Traits, such as presence of separate maxillary fenestra, otherwise only known in Hypsilophodon, show more homoplastic distributions. Phylogenetic analysis provides weak support for grouping Haya with the Chinese Cretaceous taxa Jeholosaurus and Changchunsaurus, suggesting a greater hidden diversity of such animals in Asia. The most complete prepared specimen of Haya exhibits a sizeable gastrolith mass, representing only the second occurrence among ornithopods.
The generic name and the specific name are derived from the Sanskrit for the Hindu deity Hayagriva, which characterized by a horse head. It refers to the elongate horse-like skull of this Haya and the appearance of this deity in the Buddhist art of Mongolia.
IGM 100/2017 is composed of a complete and well preserved skull with some postcranial elements associated to it.
Referred materials include IGM 100/1324, isolated left femur, IGM 100/2013, postcranial elements, IGM 100/2014, a crushed skull and postcranial elements, IGM 100/2015, a nearly complete postcranial skeleton, IGM 100/2016, a partial juvenile skull, IGM 100/2018, an isolated mandible with some teeth, IGM 100/2019, a nearly complete skull and skeleton and IGM 100/2020, postcranial fragments. One skeleton of Haya, IGM 100/2015, preserves a large mass of gastroliths. A cladistic analysis found it to form a clade with Jeholosaurus and Changchunsaurus within Ornithopoda.
Collected in the Khugenetslavkant locality by the joint Mongolian Academy of Sciences from 2002 to 2007, from the Javkhlant Formation.