A newly analyzed fossil suggests a small, feathered dinosaur from the Late Cretaceous period actively stole and consumed eggs. The findings, published in the Proceedings of the Zoological Institute of the Russian Academy of Sciences, detail a unique forelimb and claw belonging to a previously unknown genus and species, Manipulonyx reshetovi. This discovery challenges previous assumptions about the diet of alvarezsaurids, a family of dinosaurs known for their unusually small arms and long legs.
The Peculiar Anatomy of Manipulonyx
The fossil, excavated in 1979 from Mongolia’s Gobi Desert, reveals a striking appendage. Manipulonyx possessed a disproportionately large first finger alongside two much smaller secondary digits, and what appear to be spikes on its hands—an unprecedented feature for carnivorous dinosaurs. Paleontologist Denver Fowler describes the arm as “spectacular” and notes that it provides the most complete view yet of these already bizarre creatures.
From Insect Hunter to Egg Thief?
Prior research proposed that alvarezsaurids primarily fed on insects, using their short, powerful arms to excavate termite mounds. However, the Manipulonyx specimen casts doubt on this theory. According to Alexey Lopatin, a paleontologist at the Russian Academy of Sciences, the claw and fragile finger structure would have been easily damaged while digging for insects.
Instead, Lopatin and his colleagues argue that the unique shape of Manipulonyx ‘s claw and spikes indicate an adaptation for grasping, puncturing, and stealing eggs. The dinosaur would have likely snatched eggs tightly before fleeing, a behavior supported by the claw’s thin, piercing design.
Egg-Stealing in Dinosaur History
The concept of egg-stealing dinosaurs isn’t new. Oviraptor, another dinosaur found in the Gobi Desert, was initially misidentified as an egg thief until later research revealed that the fragments found near its remains likely belonged to its own clutch. Unlike Oviraptor, Lopatin believes Manipulonyx possessed the necessary adaptations to actively steal eggs from other nests.
While other researchers agree that the egg-snatching hypothesis is interesting, some remain skeptical. Fowler suggests that consuming eggs directly from the arms could have been messy given the dinosaurs’ feathered bodies. However, the discovery of Manipulonyx provides compelling new evidence supporting the possibility that at least some alvarezsaurids supplemented or even specialized in a diet of stolen eggs.
This discovery highlights how paleontological insights can evolve as new evidence emerges, reshaping our understanding of dinosaur behavior and ecology. The unique anatomy of Manipulonyx suggests a more complex and opportunistic feeding strategy than previously imagined, demonstrating that some dinosaurs were willing to snatch a meal even if it meant raiding other nests.
