Sinornithoides: Research Database
Troodontidae (Theropoda) · Early Cretaceous (~130–120 MYA) · Asia — China (Liaoning)
Research Note: Sinornithoides was a troodontid theropod from the Early Cretaceous of Liaoning, China. As a member of Troodontidae, it provides important data on small theropod diversity and the evolution of bird-like features in theropods.
| Research Finding | Status | Grade | Year | Method | Citation | Impact |
|---|---|---|---|---|---|---|
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Zelenitsky & Modesto 2002: Sinornithoides from the Early Cretaceous of China
Zelenitsky & Modesto 2002 provide comprehensive data on Sinornithoides from the Early Cretaceous of Liaoning, China, establishing its troodontid affinities and documenting small theropod diversity in the Jehol Biota
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Confirmed | A | 2002 | Fossil | Zelenitsky & Modesto, Cretaceous Research | Taxonomy |
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Pei et al. 2021: New data on troodontid diversity in the Cretaceous of China
Pei et al. 2021 provide additional data on Sinornithoides and other troodontids from the Cretaceous of China, expanding our understanding of small theropod diversity in the Jehol Biota
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Confirmed | B | 2021 | Fossil | Pei et al., Cretaceous Research | Diversity |
Active Debate: Troodontid Systematics and the Evolution of Bird-Like Theropods
The precise phylogenetic placement of Sinornithoides within Troodontidae and its relationships to other small theropods continue to be debated.
What We Still Do Not Know About Sinornithoides
- Complete skeletal morphology: Partial specimen known.
- Feather integration: Presumed based on troodontid phylogeny.
- Diet: Likely carnivorous/omnivorous.
- Social behavior: No direct evidence.
In Depth
Sinornithoides is a genus of small troodontid dinosaur that lived in China during the early Cretaceous. The holotype individual of this genus, a subadult, was found in a nesting position with its head tucked under its left arm, very similar to how another small troodontid named Mei was found. This may indicate that most, maybe even all troodontids slept in such a manner, and again illustrates how close some varieties of dinosaurs were to the birds. As a small and fast troodontid dinosaur, Sinornithoides would have been a predator of small animals such as smaller lizards and mammals, and perhaps even larger insects. One point of note about Sinornithoides, is that the sickle claw on the second toe of the feet is proportionately quite large when compared to other troodontids.
Further Reading
- A nearly complete skeleton of a new troodontid dinosaur from the Early Cretaceous of the Ordos Basin, Inner Mongolia, People’s Republic of China. - Canadian Journal of Earth Sciences 30(10-11):2163-2173. - D. A. Russell & Z.-M. Dong - 1994.
