This dino had a penchant for pilfering eggs.
A brand new evaluation of a roughly 67-million-year-old fossil forelimb and claw suggests {that a} uncommon group of diminutive Mongolian dinos could have developed to steal and eat eggs. The “exceptional” appendage was distinctive sufficient to categorise its proprietor as a brand new genus and species, Manipulonyx reshetovi, researchers report December 23 within the Proceedings of the Zoological Institute of the Russian Academy of Sciences.
“It’s a spectacular arm,” says Denver Fowler, a paleontologist on the Badlands Dinosaur Museum in Dickinson, North Dakota who was not concerned with the examine. “The truth that that is probably the most full arm of those already bizarre-looking dinosaurs is outstanding; their arms have been even weirder than we thought.”
The arm and claw have been excavated in 1979 from the Nemegt Formation in Mongolia’s Gobi Desert alongside a number of leg, vertebrae and pelvic fragments. The bones signify one member of a household of feathered dinos referred to as alvarezsaurids that ranged in measurement from 50 centimeters to 2 meters lengthy and possessed shrunken arms and prolonged legs. The specimen, which most likely got here from a 50-cm-long species, languished in museum archives in Russia till just lately, when new preparations slowly uncovered its never-before-seen options.
“Manipulonyx had a big first finger and two tiny second and third fingers, but it surely appears to have spikes on its fingers,” which is unprecedented for meat-eating dinosaurs, says Michael Pittman, a paleobiologist on the Chinese language College of Hong Kong who reported a equally weird alvarezsaurid claw in 2011.
Prior analysis recommended alvarezsaurids have been primarily insectivorous, utilizing their stubby, sturdy forearms to dig and yank termites from their mounds. However the brand new evaluation of the bones lends credence to a distinct technique. “Such a limb would have been utterly unsuitable for destroying termite mounds,” says Alexey Lopatin, a paleontologist on the Russian Academy of Sciences who studied the museum specimen. “The skinny piercing claw would have damaged off within the course of, and the delicate vestigial fingers and spikes would have been broken.”
As an alternative of looking for buried bugs, these dinos used their uniquely formed claws and spikes to select up, puncture and pilfer eggs, greedy them tightly earlier than sprinting off, Lopatin and his colleagues argue.

Egg-snatching dinosaurs will not be a novel idea to paleontology. Oviraptor, one other Gobi Desert dinosaur whose title interprets to “egg thief,” was initially thought to subsist on a weight loss plan of filched eggs. It was discovered alongside a number of egg fragments, which paleontologists initially interpreted as a remaining meal. Subsequent analysis decided these fragments probably got here from its personal brood, upending the unique speculation.
“Oviraptor didn’t eat eggs,” Lopatin says. Manipulonyx, then again, “had all of the variations to take action.”
In 2018, researchers in China even predicted {that a} totally different alvarezsaurid species might need eaten eggs, however compelling proof for the speculation was missing till now, says Lopatin.
Pittman says the egg-snatching speculation is “very fascinating” and price additional testing. Fowler agrees however isn’t but satisfied it’s a greater concept than digging for bugs. “I’m undecided if it’s terribly sensible to crush an egg in your arms after which put it down and eat it from the bottom, particularly contemplating that this household of dinosaurs was coated in feathers,” he says. A splash-and-dine meal of eggs would lead to messy plumage.
