
Manipulonyx by Conner Ashbridge.
Alvarezsaurids are highly unusual dinosaurs in that they have short but powerful forelimbs with thick claws. Typically they are interpreted as analogous to modern anteaters and similar mammals, using their claws to dig for termites and ants. However, a 2025 paper on the newly discovered Manipulonyx, a taxa with odd carpal spikes, have noted that the forelimbs are too short to reach termite mounds. Instead, these animals are interpreted as egg eaters, using the forelimbs to grab and pierce dinosaur egg shells.
While an interesting hypothesis, I feel it has its own share of problems. If alvarezsaurid arms are two short to reach termite mounds, they surely are also too small to reach eggs, as most dinosaurs (including some Mesozoic birds) burried their eggs on the ground. I also question the ecology of an obligate egg-eater; there are modern snakes of the genus Dasypeltis and Elaschistodon that do feed primarily on eggs, but they’re cold blooded animals. An endothermic dinosaurs would likely have to feed on multiple eggs per day, and there would have been times of absence like dry seasons or harsh winters.
Additionally, dinosaurs usually develop hand spikes when engaging in interpecific combat; many modern birds with spurs can attest to this. I doubt that the spikes of Manipulonyx, being hard and inert, would have been better to collect eggs than to simply fight other Manipulonyx.
Overall, the mystery of alvarezsaurid diet continues.






