‘Stunningly preserved’ dinosaur ‘mummies’ discovered in Wyoming have skin and hooves

Skeletons of duck-billed dinosaurs discovered greater than 100 years in the past are so well-preserved that they include fleshy physique elements of the extinct species embedded in skinny layers of clay, scientists say.

Specimens of Edmontosaurus annectens, identified for his or her lengthy cranium that resembles a duck’s invoice, have been present in jap Wyoming within the early 1900s. Current reexamination of these fossils by paleontologists on the College of Chicago revealed that the fossils don’t include simply bones, however mummified physique elements protected beneath a clay masks, based on a paper revealed final week in Science.

Among the many bones are “stunningly preserved” items of pores and skin, spikes and hooves, the researchers mentioned.

The “fleshy” elements are usually not fossilized flesh however reasonably delicate clay molds shaped by microbes because the animals decayed, based on the paper.

The uniform clay layers are certain by sandstone, reasonably than true fossilized smooth tissue, possible shaped as a floor template over the decaying carcass, aided by biofilms.

That is in distinction to typical smooth tissue preservation, which happens in fine-grained, oxygen-poor environments, resembling lagoons or seabeds, and ends in the fossilization of delicate elements resembling feathers and pores and skin, the researchers mentioned.

When the specimens have been first found in coarse, oxygenated river deposits, scientists assumed they have been fossilized pores and skin texture and physique elements. However additional examination of the unique skeletons — in addition to the findings of two extra mummified E. annectens, a juvenile and an grownup — proved in any other case.

The late juvenile E. annectens is the primary subadult dinosaur mummy and the primary large-bodied dinosaur with a “totally preserved fleshly define,” together with a neck and trunk crest.

The grownup specimen is the primary hadrosaurid to retain its full tail spike row. It is usually the earliest identified tetrapod with hooves, marking the primary reptile with hooved ft, based on the paper.

The midline crest and tail spikes of E. annectens reveal a “much more complicated conceal” than historic restorations have instructed, the researchers mentioned.

The species additionally has practical and morphological similarities to some fashionable squamates, the biggest order of reptiles that incorporates lizards and snakes.