Skeletons of duck-billed dinosaurs discovered greater than 100 years in the past are so well-preserved that they include fleshy physique components 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, had been present in jap Wyoming within the early 1900s. Latest reexamination of these fossils by paleontologists on the College of Chicago revealed that the fossils don’t include simply bones, however mummified physique components protected beneath a clay masks, in response to a paper printed final week in Science.
Inventory picture rendering of Edmontosaurus annectens.
Roman Garcia Mora/stocktrek Imag/Getty Photographs
Among the many bones are “stunningly preserved” items of pores and skin, spikes and hooves, the researchers stated.
The “fleshy” components are usually not fossilized flesh however moderately delicate clay molds shaped by microbes because the animals decayed, in response to the paper.
The uniform clay layers are certain by sandstone, moderately than true fossilized comfortable tissue, possible shaped as a floor template over the decaying carcass, aided by biofilms.
That is in distinction to typical comfortable tissue preservation, which happens in fine-grained, oxygen-poor environments, corresponding to lagoons or seabeds, and ends in the fossilization of delicate components corresponding to feathers and pores and skin, the researchers stated.
The hoof, preserved in part as a really skinny clay layer, caps the tip toe bone within the foot of an grownup mummy of the grownup duck-billed dinosaur Edmontosaurus annectens.
Tyler Keillor/Fossil Lab
When the specimens had been first found in coarse, oxygenated river deposits, scientists assumed they had been fossilized pores and skin texture and physique components. 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 “absolutely preserved fleshly define,” together with a neck and trunk crest.
The grownup specimen is the primary hadrosaurid to retain its full tail spike row. Additionally it is the earliest identified tetrapod with hooves, marking the primary reptile with hooved toes, in response to the paper.
The mum of a juvenile duck-billed dinosaur Edmontosaurus annectens was preserved as a dried carcass resting on its ribcage about 66 million years in the past.
Tyler Keillor/Fossil Lab
The midline crest and tail spikes of E. annectens reveal a “way more complicated disguise” than historic restorations have instructed, the researchers stated.
The species additionally has practical and morphological similarities to some trendy squamates, the most important order of reptiles that comprises lizards and snakes.
