In recent years, dinosaurs have gotten awfully cute. They’re no longer Victorian lumps of saggy muscle. A lot of them are not even frightening. They’re fuzzy, feathery little critters. But, as I’ve written before, cuteness is not what drives paleontologists to hunt for these fossils and spend years poring over them in laboratories.
Today brings another case in point. Chinese paleontologists published a report in Nature about a new fossil they’ve named Epidexipteryx hui. The fossil comes from rocks that are somewhere between 152 and 168 million years old. Much of its skeleton was preserved on a slab, along with impressions on the surface of its body that the scientists conclude were feathers. At this point, the discovery of yet another feathered dinosaur is not big news. But Epidexipteryx looks to be important for several reasons.
One is its kinship to birds. The researchers compared 363 traits on Epidexipteryx and 19 other dinosaurs and birds. Along with its feathers, Epidexipteryx has many traits that link it closely to birds, such as a humerus that’s as long as its femur. In fact, the analysis reveals this dinosaur was one of the closest relatives to Archaeopteryx and all other birds capable of flight.
Obviously, Epidexipteryx was no flier itself. It didn’t have the right feathers on its arms to give it enough lift. Nor did the many other feathered dinosaurs scientists have unearthed over the past 15 years. To understand what function feathers served before flight, paleontologists have looked to living birds. Flight feathers are just one of many different kinds found on them. Fuzzy feathers help insulate birds, and many paleontologists have proposed that insulation was one of the early adaptations of feathers on dinosaurs.
Epidexipteryx means “display wing,” and the name is apt. Its remarkable tail feathers could not have helped it fly, nor could they have kept it warm. Instead, they bear a striking resemblance to the extravagant feathers of some living species of birds, like the widowbird. Male birds use long tail feathers to attract females, possibly by advertising their good genes. The tails evolve to great lengths, even though the males have to pay a cost–either in the energy to grow them, or in the drag they create during flight.
Epidexipteryx is compelling evidence that feathers had already evolved for display before birds used them to fly. It should not be surprising that other feathered dinosaur fossils discovered so far don’t show signs of long tail feathers. Only a small number of living bird species have evolved to widowbird-like extremes, for reasons scientists don’t yet understand. Sexual selection must have been at work in Jurassic dinosaurs, just as it is at work in their living cousins, the birds. And just as birds have evolved many different ways to show off–from rooster combs to red patches on red-winged blackbirds–it makes sense that dinosaurs evolved their own courtships too.
Source: Zhang et al, A bizarre Jurassic maniraptoran from China with elongate ribbon-like feathers, Nature 23 October 2008 doi:10.1038/nature07447
October 22nd, 2008 at 10:10 pm
Hi Carl, no italicisation of the latin binomials, for shame! More seriously, just to wade in here with some shameless self promotion, a post of this beastie will be up on my blog today by one of the original authors if your readers are looking for soem more information. Cheers, Dave
October 23rd, 2008 at 2:14 am
“Obviously, Epidexipteryx was no flier itself. It didn’t have the right feathers on its arms to give it enough lift. Nor did the many other feathered dinosaurs scientists have unearthed over the past 15 years.”
It’s worth noting that many Mesozoic “feathered dinosaurs” actually did possess flight feathers, it’s just that most of these are considered “birds” and therefore (incorrectly) not “dinosaurs.” This is the kind of dichotomous taxonomy that creationists (and BANDers) love. Among “non-avian dinosaurs” Microraptor at least appears to have used it’s feathers to generate lift.
Likewise, elongate tail-feathers are actually surprisingly common among Mesozoic theropods including Confuciusornis and some Enantiornithines (usually considered “birds”) and to at least a minor degree the non-avian Caudipteryx, though Epidexipteryx puts all of these to shame.
October 23rd, 2008 at 5:17 am
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October 23rd, 2008 at 9:19 am
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October 23rd, 2008 at 4:17 pm
Do you think it would be possible for sexual selection to drive the development of feathers, but then adaptive advantages (like insulation) to take over? Are there any known instances of sexual selection and natural selection feeding off of each other? I’m thinking cuttlefish in my head, but even in that case, it’s more likely that their camouflage abilities started with natural, rather than sexual, selection.
October 24th, 2008 at 10:21 am
Do you think it is possible that the artist who created the picture being blasted all over the known world was a wack job? Have you seen the original fossil find?
http://news.nationalgeographic.com/news/bigphotos/95096577.html
How does one go from that to what you see all over? Blue tuft and ribbon appendage display “feathers” that have nothing to do with flight.
Get real folks. Here is a more level headed, referenced approach to the topic:
http://www.trueorigin.org/birdevo.asp#6
Warning: Engage your brains first before you read.
October 24th, 2008 at 6:13 pm
sbgaetal
How was an old reference relevant to a new find???
Quit the posturing – it’s embarassing! Let real paleontologists and paleoartists do their jobs!
October 24th, 2008 at 7:25 pm
sbgaetal
The photo you referenced was a completely different fossil, _Eoconfuciusornis_. Perhaps you should engage your brain before you post.
October 30th, 2008 at 6:10 am
Creationists engage their brain in ways that you and I cannot comprehend. They must be wired all backwards…
December 18th, 2008 at 3:21 pm
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