Shake Your Jurassic Tail Feather

By Carl Zimmer | October 22, 2008 1:00 pm

epidexipteryx440.jpgIn 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.

widowbirdEpidexipteryx 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

CATEGORIZED UNDER: Evolution

Comments (12)

  1. 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

  2. “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.

  3. Greg

    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.

  4. sbgaetal

    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.

  5. 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!

  6. rob

    sbgaetal

    The photo you referenced was a completely different fossil, _Eoconfuciusornis_. Perhaps you should engage your brain before you post.

  7. Kilian Hekhuis

    Creationists engage their brain in ways that you and I cannot comprehend. They must be wired all backwards…

  8. Mauro

    I think it is safe to say that feathers were shaped by sexual seleccion, each generation of females choosing mates with longer and better formed feathers. Males had to display a ritual in which they jumped while waving the “wings” up and down to impress the females. The higher jumpers were selected and that’s how they started to become more and more lighter and feathery. This is my main thing. But that hypothesis depends on when the microraptors come into the picture, since they represent a different branch of flight OR the origin of flight itself. They seem to be tree climbers and their feathers and bodies suggest pre-flight jumping from tree to tree. Does anyone know if the microraptor is found before archaeopteryx or after, or are they contemporary species? I need to know this… I can’t find the exact thing…

NEW ON DISCOVER
OPEN
CITIZEN SCIENCE
ADVERTISEMENT

Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

The Loom

A blog about life, past and future. Written by DISCOVER contributing editor and columnist Carl Zimmer.

About Carl Zimmer

Carl Zimmer writes about science regularly for The New York Times and magazines such as DISCOVER, which also hosts his blog, The LoomHe is the author of 12 books, the most recent of which is Science Ink: Tattoos of the Science Obsessed.

ADVERTISEMENT

See More

ADVERTISEMENT
Collapse bottom bar
+

Login to your Account

X
E-mail address:
Password:
Remember me
Forgot your password?
No problem. Click here to have it e-mailed to you.

Not Registered Yet?

Register now for FREE. Registration only takes a few minutes to complete. Register now »