Newly discovered dinosaur implies greater prevalence of feathers

Jul 02, 2012
Skeleton of Sciurumimus as found on a limestone slab © H. Tischlinger/Jura Museum Eichstätt

(Phys.org) -- A new species of feathered dinosaur discovered in southern Germany is further changing the perception of how predatory dinosaurs looked. The fossil of Sciurumimus albersdoerferi, which lived about 150 million years ago, provides the first evidence of feathered theropod dinosaurs that are not closely related to birds. The fossil is described in a paper published in the Proceedings of the National Academy of Sciences today.

"This is a surprising find from the cradle of feathered dinosaur work, the very formation where the first was collected over 150 years ago," said Mark Norell, chair of the Division of at the and an author on the new paper along with researchers from Bayerische Staatssammlung für Paläontologie und Geologie and the Ludwig Maximilians University.

Theropods are bipedal, mostly carnivorous dinosaurs. In recent years, scientists have discovered that many extinct theropods had feathers. But this feathering has only been found in theropods that are classified as coelurosaurs, a diverse group including animals like T. rex and birds. Sciurumimus—identified as a megalosaur, not a coelurosaur— is the first exception to this rule. The new species also sits deep within the evolutionary tree of theropods, much more so than coelurosaurs, meaning that the species that stem from Sciurumimus are likely to have similar characteristics.

"All of the feathered predatory dinosaurs known so far represent close relatives of birds," said palaeontologist Oliver Rauhut, of the Bayerische Staatssammlung für Paläontologie und Geologie. "Sciurumimus is much more basal within the dinosaur family tree and thus indicates that all predatory dinosaurs had feathers."

Newly discovered dinosaur implies greater prevalence of feathers
Mid-tail section of Sciurumimus under ultraviolet light, showing patches of preserved skin (yellow) and fine filaments (bluish lines above the vertebrae). © H. Tischlinger/Jura Museum Eichstätt

The , which is of a baby Sciurumimus, was found in the limestones of northern Bavaria and preserves remains of a filamentous plumage, indicating that the whole body was covered with feathers. The genus name of Sciurumimus albersdoerferi refers to the scientific name of the tree squirrels, Sciurus, and means "squirrel-mimic"—referring to the especially bushy tail of the animal. The species name honors the private collector who made the specimen available for scientific study.

"Under ultraviolet light, remains of the skin and feathers show up as luminous patches around the skeleton," said co-author Helmut Tischlinger, from the Jura Museum Eichstatt.

Sciurumimus is not only remarkable for its feathers. The skeleton, which represents the most complete predatory dinosaur ever found in Europe, allows a rare glimpse at a young dinosaur. Apart from other known juvenile features, such as large eyes, the new find also confirmed other hypotheses.

"It has been suggested for some time that the lifestyle of changed considerably during their growth," Rauhut said. "Sciurumimus shows a remarkable difference to adult megalosaurs in the dentition, which clearly indicates that it had a different diet."

Adult megalosaurs reached about 20 feet in length and often weighed more than a ton. They were active predators, which probably also hunted other large dinosaurs. The juvenile specimen of Sciurumimus, which was only about 28 inches in length, probably hunted insects and other small prey, as evidenced by the slender, pointed teeth in the tip of the jaws.

"Everything we find these days shows just how deep in the family tree many characteristics of modern birds go, and just how bird-like these animals were," Norell said. "At this point it will surprise no one if feather like structures were present in the ancestors of all dinosaurs."

Explore further: Oldest pterodactyloid species discovered, named by international team of researchers

More information: “Exceptionally preserved juvenile megalosauroid theropod dinosaur with filamentous integument from the Late Jurassic of Germany,” by Oliver W. M. Rauhut, Christian Foth, Helmut Tischlinger, and Mark A. Norell, PNAS, 2012.

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Shifty0x88
2 / 5 (4) Jul 02, 2012
FTA: "But this feathering has only been found in theropods that are classified as coelurosaurs, a diverse group including animals like T. rex and birds. Sciurumimusidentified as a megalosaur, not a coelurosaur is the first exception to this rule."

Just because it is the 1st exception to the rule do not mean you can generalize and say that every megalosaur had feathers. It could be entirely possible that this was the 1st and last of its kind and that this was a failed evolution experiment, and that is the reason why we always see theropods with feathers, these guys couldn't last.
rwinners
3 / 5 (2) Jul 02, 2012
Which came first, the feathers or the dino?
Deesky
4.2 / 5 (5) Jul 02, 2012
First of all - wow! That is a beautiful looking fossil (top pic) - it's a work of art!

Just because it is the 1st exception to the rule do not mean you can generalize and say that every megalosaur had feathers.

When it comes to species, 'rules' and 'exceptions' are somewhat arbitrary labels as species transcend rigid pigeonholes we'd like to confine them into. This is especially the case when we are dealing with paltry sample sizes (the fossil record) strewn over a range of millions of years and wide ranging geographies.

I do acknowledge that categorization is necessary and useful, but to be talking about 'breaking of rules' because of new finds seems a bit odd to me.
Deesky
5 / 5 (5) Jul 02, 2012
It could be entirely possible that this was the 1st and last of its kind and that this was a failed evolution experiment

Sure, it's possible, I guess, but the odds of finding such a singular specimen are astronomical. What's more, to me it makes more sense that an early evolved trait found to be useful (feathers) would be passed on to later generations and evolutionary offshoots.

Also, I dislike the term 'failed evolution experiment' because it implies that a higher power is conducting experiments in evolution and has somehow failed in this case. All species (how ever you define them) have a finite existence and quite how you define what is 'success' and what is 'failure' is pretty subjective.
JGHunter
3 / 5 (2) Jul 03, 2012
All species (how ever you define them) have a finite existence and quite how you define what is 'success' and what is 'failure' is pretty subjective.


I guess what is meant is that something is successful if it endures long enough to mutate and evolve further, ie. the genetic mutation was not necessarily helpful (when it first happened) but it wasn't detrimental, so the creature endured the change to go on and produce generations that could evolve further.
PhotonX
5 / 5 (2) Jul 03, 2012
Sure, it's possible, I guess, but the odds of finding such a singular specimen are astronomical.
What you're saying is that such a generalization would apply to virtually all fossils, at least vertebrates, because there likely is a buttload of a particular type just for us to be lucky enough to find even one. Makes sense to me, but I'm 4 hours past my bedtime, when anything sounds good.
.
I guess kevintrs has the night off, or we would have heard by now that science is foolish to state the fossil is 150 MYO, since his holy book tells him the Earth is only 6000 years old. I'd better stop now before I start channeling him.
kevinrtrs
1.6 / 5 (12) Jul 03, 2012
This dinosaur represents a difficult problem for evolutionists. The dinosaur is encased in limestone in the normal opisthotonus position.
This very fact creates problems with regard to the timing of the death as well as the usual assumptions on the length of time of formation of limestone in that clearly a fossil has to be formed very quickly, otherwise the body rots away.
Yet here we find a fossil buried completely in limestone, which supposedly takes millions of years to accumulate. Furthermore, the opisthotonus position is indicative of a high temperature fluid, in this case water.
So the dinosaur had to have died and be encased quickly in a high temperature calcium carbonate limestone sediment. With no millions of years required.
Now, the fact that thousands of dinosaur fossils can be found in the bone yards in one heap, suggests that the force which buried them in sediment must have been ginormous indeed.
The investigation of such forces is currently a hot topic in geology.
antialias_physorg
5 / 5 (5) Jul 03, 2012
This dinosaur represents a difficult problem for evolutionists. The dinosaur is encased in limestone in the normal opisthotonus position.

So where exactly is the 'problem'? Especially with regard to evolution?

You say a lot of stuff in your post - but you don't make any argument that would support your point.
Torbjorn_Larsson_OM
2.5 / 5 (2) Jul 03, 2012
The press release is much more confusing than the paper. Dinosaurs divides into Theropoda, Ornithischia & Sauropodomorpha. [Wikipedia] The abstract claims feather like structures found in Ornithischia, making this of an early theropod a strengthening as well as (I assume) an earlier data point. It tests an older hypothesis once again.

@ rwinners: Ha! That is what I came up with to comment in the local media. Great synapsid minds and all that.

@ antialias:

Indeed, this is a successful test of evolution (as well as feather trait ancestry on its own).

Our troll keeps using that word. I do not think it means what he thinks it means.

Next high point in the movie drama, see the troll drink the cup with science and fall dead from having no tolerance for facts.
Archea
3 / 5 (1) Jul 03, 2012
The question is, why/how these dinosaurs evolved feathers, if they couldn't fly.
Deesky
5 / 5 (3) Jul 03, 2012
The question is, why/how these dinosaurs evolved feathers, if they couldn't fly

Feathers evolved from scales. Today, the feathers on a developing chick begin as bristles rising up from its skin. In bird embryos these bristles erupt from patches of skin cells called placodes.

Reptiles also have placodes, however in a reptile embryo each placode switches on genes that cause only the skin cells on the back edge of the placode to grow, eventually forming scales.

So going from scales to feathers would require a simple genetic change causing placode cells to grow vertically through the skin rather than horizontally. Thereafter only minor modifications would have been required to produce increasingly elaborate feathers.

As to why they evolved, the leading hypothesis is in order to be seen - to attract the opposite sex using a range of colors, patterns, and iridescent sheens, like many birds today. Look at lengths to which peacocks go.
C_elegans
not rated yet Jul 08, 2012
Archaea, feathers are generally quite useful. They can be fluffed up to keep warm, or oiled to keep dry. They can be long, short, colored, textured or scented. I could think of a at least 100 things to do with feathers that did not involve flying. What do mammals do with hair?

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