Scientists Find a Mammal's Foot Inside a Dinosaur, a Fossil First - Gizmodo

Paleontologists taking a 2nd look astatine a taxon of small, four-winged dinosaur person recovered a fossilized mammalian ft successful the predator’s stomach.

It’s the archetypal factual grounds of dinosaurs eating mammals, the researchers say. Specimens of the dinosaur, Microraptor zhaoinus, person been discovered containing past birds, fish, and lizards, truthful the mammalian find is conscionable the latest known root of macromolecule for this spunky hunter. The squad who re-scrutinized the Microraptor fossil published their findings contiguous successful the Journal of Vertebrate Paleontology.

“It truly demonstrates the generalist fare successful this tiny feathered dinosaur,” said Hans Larsson, a paleontologist astatine McGill University and the study’s pb author, successful an email to Gizmodo. “Adding mammals to the paper shows conscionable however un-specialized this dinosaur was.”

The tree-dwelling Microraptor lived during the aboriginal Cretaceous, and specimens person been recovered crossed what is present northeast China. The fossil-rich portion is called the Jehol Biota, and its well-preserved treasures are a large assets for knowing nuances of dinosaur anatomy, arsenic good arsenic details astir antithetic animals’ ecological niches.

Microraptor is thought to person lived successful trees, gliding astir the Cretaceous forests looking for morsels connected branches arsenic good arsenic connected the ground. The precocious studied specimen is the holotype, meaning it was archetypal of its taxon to beryllium recovered and named. It’s lone precocious been revisited aft its find backmost successful 2000. The caller investigation revealed the mammalian foot—a seemingly unprecedented find.

The researchers couldn’t place the peculiar mammal species, but the foot’s preservation wrong Microraptor allowed them to recognize its ecological niche and, obviously, its predators.

“Gut contents are astonishing snapshots into the fare of fossil animals, but they are truthful uncommon that it tin beryllium hard to fig retired whether the preserved ‘last meal’ represents the animal’s mean fare oregon a weird, one-off lawsuit that lucked into getting fossilized,” said Stephanie Drumheller-Horton, a paleontologist astatine the University of Tennessee, Knoxville, who was not affiliated with the caller paper, successful an email to Gizmodo.

“Microraptor is shaping up to beryllium a precise absorbing objection to that rule, with multiple, beautifully fossilized specimens preserving antithetic ‘last meals,’” Drumheller-Horton added. “Taken together, the authors marque a compelling lawsuit that this small theropod wasn’t a peculiarly picky eater, eating each sorts of small-bodied animals successful its environment.”

The mammal ft seemingly did not beryllium to a distant quality ancestor; the squad said it had similarities to the morphologies of Sinodelphys, Yanoconodon, and Eomaia, each past taxon of aboriginal mammals that looked astir similar opossums oregon rodents.

The ft belonged to an carnal astir the size of a mouse. The team’s investigation recovered the critter wouldn’t person been a bully climber—an indicator that Microraptor whitethorn person occasionally swooped down to the wood level for feeding.

“The ft seems wholly intact, and frankincense was swallowed whole. How overmuch of the mammal was swallowed is unknown,” Larsson said. “However, determination were respective different unidentified bones astir the ft successful the rib cage, truthful I fishy that much of that mammal was consumed.”

The researchers could not find whether the carnal was hunted and killed oregon if the feathered dinosaur had scavenged its body.

Given the luck paleontologists person had with the Jehol Biota truthful far, it whitethorn conscionable beryllium a substance of clip earlier different meal-laden specimen offers much insights astir the Cretaceous nutrient scene.

More: A Shark, Eating a Squid, Eating a Lobster, successful One Fossil