Daliansaurus
Small troodontid dinosaur with an extra large foot claw.
Tomopteryx · CC BY-SA 4.0
Here is the rewritten encyclopedia entry for **Daliansaurus**:
**Daliansaurus** ("Dalian reptile") is a genus of small troodontid theropod dinosaur from the Early Cretaceous of China. The only species, *D. liaoningensis*, was named in 2017 by Shen and colleagues based on a nearly complete, three-dimensionally preserved skeleton. It measured about 1 meter (3 ft 3 in) long. Unlike most paravians, which have a single enlarged "sickle claw" on the second toe, *Daliansaurus* also possesses a large claw on the fourth toe, though it is not necessarily matching the second claw in length or being more robust, and its flexor tubercle is not well-developed. It also has unusually long metatarsal bones and appears to have bird-like uncinate processes on some ribs, a feature also seen in some other theropods.
The skull is proportionally larger than that of *Mei*, with a smaller nostril. The premaxilla has a flattened projection above the nostril (unlike the rod-like shape in *Sinovenator*) and a straight projection below it (like *Sinusonasus*). The lower jaw has a straight bottom edge, like *Mei* and *Sinornithoides*, and contains at least 24 teeth, fewer than *Sinovenator* (27). The upper jaw holds at least 21 teeth, with the four premaxillary teeth being D-shaped and not recurved. The back teeth have small serrations on their rear edges.
The skeleton includes at least nine neck vertebrae, likely thirteen back vertebrae, five hip vertebrae, and at least twenty-eight tail vertebrae. Among the hip vertebrae, the fifth has the widest transverse processes (the third is widest in *Sinovenator*), and the front margin of these processes is less concave. Two back vertebrae bear curved, rod-like uncinate processes on their ribs, a feature seen in some other theropods and present in some troodontids. The front tail chevrons are long, plate-like, and directed backward, similar to *Sinornithoides*.
The humerus is relatively long, with a deltopectoral crest taking up 24% of its length. In the hand, the first metacarpal is strongly curved vertically, the second metacarpal is shorter than the third (the opposite of *Sinovenator* and *Sinusonasus*), and the first digit is the most robust, with a deeply grooved claw. The third digit has the smallest claw. The ilium is proportionally larger relative to the femur than in *Sinornithoides* or *Mei*, and its rear bottom edge is very conc
- Length
- approximately 1 metre (3 ft 3 in)
- Time period
- Early Cretaceous (~126 Ma, Barremian epoch)
- Location
- Lujiatun Beds, Yixian Formation, Liaoning, China
- Type species
- Daliansaurus liaoningensis
- Notable features
- Large claw on fourth digit, long metatarsals, uncinate processes
- Closest relatives
- Sinovenator, Sinusonasus, Mei (group Sinovenatorinae)
Quick Facts
- Taxon
- Daliansaurus
- Type Species
- Daliansaurus liaoningensis
- Type Species Authority
- Shen et al., 2017
Facts from the source article.
Lore & Background
The skull of Daliansaurus measures 13.8 cm long and is proportionally larger than that of Mei. It has at least 21 upper and 24 lower tooth positions, fewer than Sinovenator. The ribs of two dorsal vertebrae bear uncinate processes, curved rod-like projections similar to those of Velociraptor, Linheraptor, and Heyuannia—a feature also present in some other troodontids. The metatarsal bones are proportionally much longer than in other troodontids, suggesting enhanced running capabilities.
Reader's Guide
Daliansaurus is significant for expanding the known diversity of Early Cretaceous troodontids from the Yixian Formation, a volcanically-influenced region with a cold climate. Its most distinctive trait—an enlarged claw on the fourth digit of the foot, equal in length and more robust than the sickle claw on the second digit—challenges typical assumptions about troodontid foot morphology. The presence of bird-like uncinate processes further blurs the line between non-avian dinosaurs and birds. Phylogenetic analysis places Daliansaurus within the Sinovenatorinae, a group of closely related troodontids including Sinovenator, Sinusonasus, and Mei, with Daliansaurus and Sinusonasus forming a subgroup to the exclusion of Sinovenator. The long metatarsals suggest Daliansaurus was a capable runner, adapted to its cold, volcanic environment. Its discovery underscores the rapid evolution and ecological specialization of troodontids in the Early Cretaceous of Asia.
Did You Know?
- Daliansaurus has a large claw on the fourth digit of the foot, in addition to the sickle claw on the second digit, though the fourth claw is not necessarily as long or robust as the second.
Gallery
Frequently Asked Questions
What is Daliansaurus?
Daliansaurus is a small troodontid theropod from the Early Cretaceous of China, represented by a single species, D. liaoningensis. Shen and colleagues named it in 2017 after recovering a nearly complete, three-dimensionally preserved skeleton.
What makes Daliansaurus's feet unusual?
Most paravian dinosaurs have a single enlarged sickle claw on the second toe, but Daliansaurus also carries a notably large claw on its fourth toe. This extra enlarged digit distinguishes it from many of its close relatives within Sinovenatorinae.
When and where did Daliansaurus live?
It roamed during the Barremian stage of the Early Cretaceous, roughly 126 million years ago. Its fossils come from the Lujiatun Beds of the Yixian Formation in Liaoning Province, China.
How big was Daliansaurus?
At approximately one metre (about 3 ft 3 in) long, it was a small-bodied theropod. Its skeleton also features elongated metatarsals and prominent uncinate processes on the ribs.
What is Daliansaurus's closest relative?
Daliansaurus sits within the Sinovenatorinae, a troodontid subgroup that also includes Sinovenator, Sinusonasus, and Mei. Its position in that clade makes it one of the more basal members of the lineage.
More in Feathered dinosaurs 1-24
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