Posted on 09/15/2021 11:03:51 AM PDT by Red Badger
Close-up of the skin, with ridges marked. (Hendrick and Bell, Cretaceous Research, 2021
https://www.sciencedirect.com/science/article/abs/pii/S0195667121002421#fig3
The outer parts of long-dead creatures don't easily make it into the fossil record. That's why this incredibly well-preserved skin of an iconic carnivorous dinosaur is such a treat – a new analysis reveals a complex coat of scales, studs, thorns, bumps and wrinkles.
The remains of this bizarre-looking predator, known as the horned abelisaurid (Carnotaurus sastrei), were first discovered in Patagonia in 1984. At the time, it was the first meat-eating dinosaur ever found with fossilized skin, and the exquisite impressions covered nearly every part of the predator, from head to tail.
At times, the jagged surface almost resembles Australia's thorny devil (Moloch horridus), and yet the ridges on some other scales remind scientists of an elephant hide. Not anywhere is there even a hint of a feather.
Only the fossilized skin on the abelisaurid's horned head was missing; now, scientists have properly analyzed and described the discovery in close detail.
Unlike other, brief descriptions of the skin prints, the fresh analysis has found no evidence that the dinosaur's scales were arranged in irregular rows, or that they were different sizes depending on where they were found on the body (as we see on some modern lizards, for example).
For instance, the scales don't get smaller as they spread further down the tail and away from the core of the dinosaur's body. Instead, the largest scales appear randomly scattered across the thorax and the tail.
A new artist's reconstruction of Carnotaurus, with scaly skin. (Jake Baardse)
"By looking at the skin from the shoulders, belly and tail regions, we discovered that the skin of this dinosaur was more diverse than previously thought, consisting of large and randomly distributed conical studs surrounded by a network of small elongated, diamond-shaped or subcircular scales," describes paleontologist Christophe Hendrickx from the Unidad Ejecutora Lillo in San Miguel de Tucumán.
Despite feathered dinosaurs being more commonplace than we once assumed, not all of these prehistoric creatures evolved such flashy decorations.
Even dinosaurs who came from the same branch as modern birds didn't necessarily possess feathers. Large, terrestrial carnivores, such as the T. rex and the horned abelisaurid, really did seem to have scaly, lizard-like skin.
Both of these iconic predators belonged to a branch of hollow-boned, two-legged dinosaurs known as theropods, which modern birds later branched from.
But this specimen of C. sastrei has the best-preserved skin of any non-avian theropod, researchers say. Altogether, it includes six fragments of skin taken from the neck, the shoulder girdle, the thorax, and the tail.
Location of the specimens with skin. (Jake Baardse)
The largest patch comes from the anterior part of its tail. Here, the smallest scale measures only 20 millimeters in diameter, and yet sometimes these tiny flakes of skin can be found smooshed between other scales twice as large.
These much bigger, feature scales are almost domed in appearance, akin to the domed scales found on Diplodocus – a long-necked herbivorous dinosaur. Others are shaped more like diamonds, with much longer lengths than widths; these resemble the scales seen on tyrannosaurids that also lived in the Late Cretaceous, roughly 70 million years ago.
Why the horned abelisaurid once possessed such a wide range of large and small scales is another mystery altogether.
In 1997, scientists suggested the large, conical scales found on Carnotaurus existed for "some degree of protection during confrontation", but the authors of this new analysis say these scales would do little good against teeth.
"Alternatively, in Carnotaurus and more broadly among dinosaurs, feature scales may simply have served a display/coloration function," they suggest.
This is similar to the feathers on modern birds, which can serve as mere displays or for flight. Given that feathers are thought to have evolved from scales, such similar diversity may be no coincidence.
The scales of C. sastrei (A-E) compared to other dinosaurs. (Hendrick and Bell, Cretaceous Research, 2021)
Yet other similarities are harder to pin down. Some of the most intriguing scales on the horned abelisaurid, for instance, come from its tail, where certain flakes contain an arrangement of vertical ridges or grooves.
The authors say these parallel lines look almost like the wrinkles on elephant skin, and given that both the theropod and the African elephant are large terrestrial animals without sweat glands living in warmer climates, the authors suspect these ridges may hold similar functions. (African elephants have wrinkles on their skin to increase surface area and more effectively shed excess heat via evaporation.)
"While we do not claim that Carnotaurus and elephants necessarily thermoregulated in the same ways (i.e. using evaporative cooling), we note here that they share distinct gross morphological similarities in their integument, despite one having scales and the other having a highly modified mammalian epidermis," the authors write.
Regardless of the specifics, they maintain, theropod skin is likely to have played at least some role in thermoregulation. Future research on the scaly skin of early dinosaurs may reveal far more than simply what they looked like. It might also tell us how they lived.
The study was published in Cretaceous Research.
PinGGG!....................
I’ve always thought it was peculiar that there’s no historical record of any dinosaur fossils pre Darwin’s theory of evolution.
Didn’t Thomas Jefferson find some bones and begin collecting?
The stories of Dragons may have originated from the discovery of fearful looking fossils.
There were.
The Chinese called them “dragon bones.”
A study of a dinosaur femur in 1676 determined that it was from a large, unidentified animal, then went off the tracks suggesting that it came from a giant or a Titan.
So there were dinosaur fossils, but they were mostly un-identified as such.
later
“I’ve always thought it was peculiar that there’s no historical record of any dinosaur fossils pre Darwin’s theory of evolution.”
Sure there was... They just didn’t have a clue what they were, or had yet invented the definition of “Dinosaur”. Before that they were most likely considered “Dragon” fossils. And dragons go way back...
Yep...
“Fascinating...”
I see yet another Jurassic park movie with the horned one.
Well, it isn’t true. The oldest attributable find is in the late 1600s, and in the 1830s and 1840s there were a number of finds of bones and tracks. They just were attributed to different things, like giant iguanas, or the tracks of mythical ravens.
“Yeah,I want to see the animals in between on the evolutionary scale.”
You first have to find the very few that survived the extinction event. 99.9% never had a chance to evolve.
https://www.amnh.org/exhibitions/dinosaurs-ancient-fossils/extinction/dinosaurs-survive
If you’re extinct and you know it, clap your hands...
Dang!
Did you have to post an article about Hillary?
Now my day will be spent at the range working off the sexual thoughts...
Even earlier. There is mention of finding Giant’s bones in Homer’s Iliad.
Thanks Red Badger.
LOL! I was just thinking, what's up with the tiny arms. I mean, why even bother?
ISWYDT!...................
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.
