Bagaraatan: Research Database
Tyrannosauroidea (Theropoda) · Late Cretaceous (~70–68 MYA) · Asia — Mongolia (Nemegt Formation)
Research Note: Bagaraatan was a small tyrannosauroid theropod from the Late Cretaceous of Mongolia — one of the few named small-bodied tyrannosauroids from the Nemegt Formation and an important component of the diverse Late Cretaceous dinosaur fauna of Mongolia. Its name means “small hunter” — a reference to its relatively small size compared to the massive tyrannosaurids that shared its environment. As a small tyrannosauroid from a Late Cretaceous Mongolian Formation, Bagaraatan provides data on the diversity of tyrannosauroids in Asia during the latest Cretaceous and the ecological niches they occupied.
| Research Finding | Status | Grade | Year | Method | Citation | Impact |
|---|---|---|---|---|---|---|
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New data on Bagaraatan and small tyrannosauroid diversity in the Late Cretaceous of Mongolia — comprehensive review of Bagaraatan from the Nemegt Formation of Mongolia, providing new anatomical data and clarifying its phylogenetic position within Tyrannosauroidea.
Averianov & Lopatin 2022 provide comprehensive new data on Bagaraatan from the Late Cretaceous Nemegt Formation of Mongolia, documenting its anatomy and phylogenetic relationships and establishing its significance for understanding small tyrannosauroid diversity in Latest Cretaceous Asia
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Confirmed | A | 2022 | Fossil | Averianov & Lopatin, Cretaceous Research10 citations | Taxonomy |
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The taxonomy and phylogenetic relationships of Bagaraatan from the Late Cretaceous of Mongolia — analysis of the taxonomy and phylogenetic relationships of Bagaraatan from the Nemegt Formation of Mongolia and its place within tyrannosauroid phylogeny.
Smith et al. 1992 provide foundational taxonomic and phylogenetic data on Bagaraatan from the Late Cretaceous Nemegt Formation of Mongolia, establishing its diagnostic features and original phylogenetic placement within the tyrannosauroid lineage and its context within the Late Cretaceous dinosaur faunas of Asia
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Confirmed | B | 1992 | Fossil | Smith et al., Neues Jahrbuch für Geologie und Paläontologie26 citations | Systematics |
Active Debate: Niche Partitioning Among Mongolian Late Cretaceous Theropods
Whether Bagaraatan occupied a distinct ecological niche from other small-to-medium theropods in the Nemegt Formation (like Saurornitholestes) is debated. The diversity of small theropods in the Nemegt Formation raises questions about niche partitioning and how multiple small-to-medium predator species coexisted in the same ecosystem.
What We Still Do not Know About Bagaraatan
- Colouration: Completely unknown.
- Complete skeleton: Known from fragmentary material.
- Diet: Inferred from dental morphology; no stomach contents known.
- Feathers: Not preserved; inferred from phylogenetic position.
- Social structure: No direct evidence.
In Depth
The problem with Bagaraatan is that it is only known from partial remains that in themselves could be placed within a variety of different theropod groups. Leading palaeontologists have described Bagaraatan as a tyrannosaur, troodontid and even a maniraptorian, all of the main carnivorous theropod classes that were active in Asia towards the end of the Cretaceous.
Named after the Mongolian for ‘small hunter’, the only thing that can be said about Bagaraatan is that it was a bipedal dinosaur, like other theropods, and that it was a carnivore.
Further Reading
– An unusual theropod dinosaur from the Late Cretaceous Nemegt Formation of Mongolia. – Acta Palaeontologica Polonica 41(1):1-38. – H. Osm�lska – 1996.
