125-million-year-old Spinolestes Xenarthrosus Fossil Has Hair And Inner Organs

Posted: Oct 14 2015, 2:31pm CDT | by , Updated: Oct 14 2015, 3:00pm CDT, in News | Latest Science News


125-million-year-old Spinolestes Xenarthrosus Fossil has Hair and Inner Organs
Skeleton of the Cretaceous mammal Spinolestes with preserved fur shadows. The outer ear can be seen at the upper edge of the photo (arrow). Credit: Georg Oleschinski

A newly discovered fossil is the best preserved and oldest fossil found to date. Scientists refer to it as Cretaceous furball.

Dinosaur scientists are on a roll lately. We now know dinosaur feathers and the color of dinosaurs. Just this week we also learned the body temperature of the prehistoric animals.

Now we can add hair and inner organs to our knowledge about dinosaurs. 

A new 125-million-year-old fossil mammal discovered in Spain is the best preserved fossil by 60 million years.

The dino is called Spinolestes xenarthrosus and was fossilized with intact guard hairs, underfur, tiny hedgehog-like spines and even evidence of a fungal hair infection. 

The well-preserved fossil also contains an external ear lobe, soft tissues of the liver, lung and diaphragm, and plate-like structures made of keratin known as dermal scutes.

The microscopic structures of hair and spines in Spinolestes are the earliest-known examples in mammalian evolutionary history.

"Spinolestes is a spectacular find. It is stunning to see almost perfectly preserved skin and hair structures fossilized in microscopic detail in such an old fossil," said study co-author Zhe-Xi Luo, PhD, professor of organismal biology and anatomy at the University of Chicago. "This Cretaceous furball displays the entire structural diversity of modern mammalian skin and hairs."

The Las Hoyas Quarry in east-central Spain was once a lush wetland with a thriving diversity of life around 125 million years ago during the early Cretaceous period. 

The Spinolestes xenarthrosus lived in the Cretaceous period and belonged to an extinct lineage of early mammals known as triconodonts. 

The fossil is 24 cm in length and is estimated to have weighed around 50 to 70 grams, about the size of a modern-day juvenile rat. 

Its teeth and skeletal features indicate it was a ground-dweller that ate insects. 

"Hairs and hair-related integumentary structures are fundamental to the livelihood of mammals, and this fossil shows that an ancestral, long-extinct lineage had grown these structures in exactly the same way that modern mammals do," Luo said. "Spinolestes gives us a spectacular revelation about this central aspect of mammalian biology."

The discovery is described by scientists from the Autonomous University of Madrid, University of Bonn and the University of Chicago in a study titled "A Cretaceous eutriconodont and integument evolution in early mammals" that will be published in Nature on Oct. 15.

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<a href="/latest_stories/all/all/2" rel="author">Luigi Lugmayr</a>
Luigi Lugmayr () is the founding chief Editor of I4U News and brings over 15 years experience in the technology field to the ever evolving and exciting world of gadgets. He started I4U News back in 2000 and evolved it into vibrant technology magazine.
Luigi can be contacted directly at ml@i4u.com.




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