Linhevenator tani

Overview

Linhevenator tani is a troodontid dinosaur with short, robust arms. The bodies of bird-related theropods did not take just one form. This dinosaur reveals evolution in which arms and legs changed in different directions.^[1]

Key facts

The humerus is about 40% of the femur’s length. Shortened arms and a strongly developed second toe occur in one body. This suggests how similar features seen in other theropods can arise within different groups.^[1]

Time and place

It is a dinosaur from the Campanian Age of the Late Cretaceous, around 80–70 million years ago. Fossils came from the Wulansuhai Formation at Bayan Mandahu in present-day Inner Mongolia, China. A specimen collected during fieldwork in 2009 became the starting point of the research.^[1]

The time range describes source context, not the complete duration of this species.

Size, form and skeleton

The type specimen’s femur was estimated at about 24cm long, its skull at about 22cm, and its body mass at about 23kg. The short humerus has a large projection for muscle attachment. This arm shows that length and robustness are different features.^[1]

Habitat and reproduction

Did short arms still play important roles in life? Researchers proposed that they may have moved strongly inward or backward. Grasping food, digging, and climbing were discussed as possible explanations.^[1]

Fossil discovery

LH V0021 preserves the head and lower jaw, back vertebrae, scapula and humerus, femur, and a nearly complete left foot. A 2011 study compared these regions together. Particularly important was the ability to read forelimb and hind-limb proportions in one individual.^[1]

References

1. Xu, X., Tan, Q., Sullivan, C., Han, F. & Xiao, D. (2011). “A Short-Armed Troodontid Dinosaur from the Upper Cretaceous of Inner Mongolia and Its Implications for Troodontid Evolution.” PLOS ONE 6(9): e22916. DOI: 10.1371/journal.pone.0022916.
2. Suzuki et al. (2002), “A New Specimen of Shuvuuia deserti Chiappe et al., 1998 from the Mongolian Late Cretaceous, with a Discussion of the Relationships of Alvarezsaurids to Other Theropod Dinosaurs,” Contributions in Science 494; DOI 10.5962/p.226791.
3. Xu et al.2011 — Linhevenator tani, a short-armed troodontid dinosaur

Research questions

Are dinosaurs with similar claws always close relatives? Linhevenator prompted reconsideration of changes in troodontid feet and arms. Comparing the whole combination of body features rather than only one or two is central to evolutionary research.^[1]

Observation

Alternate between the short, robust upper arm and strongly developed second toe. Compare how different arm and leg proportions can be within one dinosaur.^[1]