Dino-bat: a new flying dinosaur with membranous wings

The evolution of flight in birds must have involved many dead ends, including all those dinosaurs with feathers that never evolved to the flying or gliding stage, or even the flying lineages that went extinct—like all dinosaurs except the single lineage that produced modern birds—when the asteroid whacked us at the end of the Cretaceous. A just-discovered species of dinosaur, described in a new paper in Nature by Xing Xu and colleagues (reference and free link at bottom), was almost certainly one of those failed experiments in flying or gliding.

The species is remarkable for two things. First, instead of having feathered forelimbs like the early ancestors of birds, it had a naked membrane stretched between the digits of its forelimbs and its body. (It did have feathers, but not on the wing membrane.) In that way it was like bats or pterodactyls. But pterodactyls weren’t dinosaurs, and so this finding, which is a winged theropod like its feathered cousins, is unique.

Further, the beast had a long bone which was an evolved extension of the wrist bone: a bone that almost certainly supported the wing membrane and, in the fossil, appears connected to that membrane. This, too, is unique in dinosaurs, but can be seen in other flying or gliding creatures like “flying” squirrels (they don’t fly, of course, but glide), the gliding marsupial “squirrel,” the ankles of some bats, and the pterosaurs. (Do recall that the “radial sesamoid” of the panda—the “panda’s thumb” made famous by Stephen Jay Gould, was also an extension of the wristbone that helped the panda strip leaves from bamboo.)

Sadly, only one specimen of this beast was found, and it’s missing the rear bits, including the crucial tail, which could have given us some information about how it glided or flew. In fact, we have no idea whether this one glided, flew, or both.

The species was named Yi qi (surely the shortest species name we have), which is Mandarin for “strange wing,” and is pronounced, according to the authors, “ee chee.”  Here’s the one specimen they found in China, dating from the Upper-middle Jurassic (ca. 160 million years ago). The scale bar at upper left is 2 centimeters (about 0.8 inches). There’s a diagram below showing the bones and what they represent:

Screen Shot 2015-04-30 at 10.35.15 AM

You can see the feather impressions above, and they’re outlined in light gray in the diagram below. There are filamentous feathers all over the body, though not on the membrane.

Screen Shot 2015-04-30 at 10.35.45 AM

So here are the crucial bits: the “styliform elements” that are an extension of the wrist, certainly produced by selection to support the membrane.  Those bits are represented by “lse” (left styliform element) and “rse” (right styliform element) in the diagrams above.

In the picture below the right styliform element is singled out (“ru” and “rr” are the ulna and radius respectively, the lower arm bones that we also have. The best way to see that these bones are extensions from the wrist is in the yellow diagram above, where the left styliform element (“lse”) extends out to to the left from the wrist, where the fingers (lmd [left manual digits] 2, 3, and 4 originate.

Screen Shot 2015-04-30 at 12.39.11 PM

The shot below shows patches of membranes; as the authors say, “sheet-like soft tissue associated with the right forelimb (yellow arrows point to patches of sheet-like soft tissue)”.

Screen Shot 2015-04-30 at 10.46.15 AM

Finally, here’s a closeup showing both feathers and membrane; as the authors say, “comparison of sheet-like soft tissue (above digit II) and individual feathers (below digit II).” You can see this bit labeled as “rmd2” in the big photo and diagram above. The distinction is clear between filaments and membrane!:

Screen Shot 2015-04-30 at 11.25.34 AM

Here’s the authors’ reconstruction of the skeleton, which closely resembles that of other theropods with wings, and you can see the long wrist-extension bone going from upper left to lower right. The main “regular” finger supporting the wing is digit #4, which is the big one with the claw almost touching the ground:

Screen Shot 2015-04-30 at 10.47.05 AM

There’s an analysis of the phylogeny of this specimen, but that needn’t detain us here; suffice it to say that it nests within the other theropod dinosaurs, and so is not at all a pterosaur.

Here’s an imaginative reconstruction of Yi qi from ScienceNews (the tail and rear bits are imaginary, as we don’t have them!):

ay_glidinghero_free

From: DINOSTAR CO. LTD

For comparison, here’s a pterosaur, also showing the wrist extension (the small “swordlike” bone coming off pointing at the shoulders), and the enormously enlarged single digit that supported the wing membrane. That was also digit #4, so there’s a case of convergent evolution here with the specimen above.  You can also see that the rest of the fingers simply stuck out from the wing.

NYCTOSR3

And here’s a pterosaur reconstruction from dinosaurjungle.com. The eentsy “fingers” sticking out from the wing may have helped it clamber about. In trees or on cliffs:

focus_pterosaur2
In contrast, bats differ in two ways. Four of their major digits—instead of one—support the wing (a single finger sticks out), and in this case there’s no wrist extension bone, though there appears to be one in the rear leg “wrist”:

bat skeleton:

bat vs skeleton

So, what we have is one of evolution’s luxuriances: a cool lineage that may well have included fliers or gliders, but didn’t form an ancestor of modern birds—though it may have been close to that ancestor.  It doesn’t tell us much about how modern birds evolved, but does affirm that the lineage we have today, as with many other groups like horses, involved many related branches that died out without leaving descendants.  Modern birds are the lucky ones (especially the ones that eat my seeds!).

h/t: Ant

_______

Xu, X., et al. (2015). A bizarre Jurassic maniraptoran theropod with preserved evidence of membranous wingsNature advance online publication.

106 Comments

  1. Posted April 30, 2015 at 1:17 pm | Permalink

    That’s very cool.

  2. Barry Lyons
    Posted April 30, 2015 at 1:19 pm | Permalink

    Excellent. I saw the piece in the Times today and wanted more details. Thanks for providing them.

  3. Posted April 30, 2015 at 1:20 pm | Permalink

    Twinkle, twinkle, little bat!
    How I wonder what you’re at!
    Up above the world you fly,
    Like a tea tray in the sky.
    Twinkle, twinkle, little bat!
    How I wonder what you’re at!

    b&

    • Jeff Rankin
      Posted April 30, 2015 at 3:25 pm | Permalink

      Dino-bat, Dino-bat
      Is it a bird or a wing’ed-rat?

      Flys around, on membraneous wings
      Feathers too, and a tiny brain.

      Look out!
      Here comes the Dino-bat!

      O’er a 100 million years ago,
      Glidin’ on the wind, look out b’low!

      Multi-fingered flying death,
      Swooping low, mammals take a breath.

      Look out!
      Here comes the Dino-baaaaaat!

  4. Posted April 30, 2015 at 1:29 pm | Permalink

    Thanks, that was an interesting read with my lunch.

  5. Captain
    Posted April 30, 2015 at 1:35 pm | Permalink

    I don’t comment on these science articles because I haven’t nearly the expertise to add anything, but as to your concerns earlier about how your audience valued them, I value them as much as if not more than the religion articles – I actually learn something with these!

    • Captain
      Posted April 30, 2015 at 1:36 pm | Permalink

      Which isn’t to say that the religion articles aren’t well-done or informative, just that I already agree with almost everything you have to say

  6. Raymond Freeman-Lynd
    Posted April 30, 2015 at 1:44 pm | Permalink

    The “experimental” aspect of the development of flight among theropods and that this is something expected from evolution is what I emphasize in the course I teach on dinosaurs, and which is also emphasized in the NOVA episode “The Four-Winged Dinosaur.”

  7. barn owl
    Posted April 30, 2015 at 1:51 pm | Permalink

    From a comparative embryology/anatomy perspective, the skeletal elements in the wings of Yi qi seem very bird-like. Digits 2, 3, and 4 are those you see labelled in images of the developing wings of chicken embryos; however, the specific arrangements and numbers of phalanges and metacarpals are different.

    IIRC, in modern birds, the metacarpals of digits 3 and 4 are fused (or appear so) in the “primaries” portion of the wing, and each has some phalanges. Digit 2 just has a phalanx, and no metacarpal (again, IIRC). In addition to the special styliform element, Yi qi has metacarpals for each of digits 2, 3, and 4, and lots of phalanges for digit 4 (phIV1-4 in one of the inset photos above).

    • Posted April 30, 2015 at 4:48 pm | Permalink

      From a paleogenomic perspective that variation may be one of the most interesting data points in working out the regulatory cascade mutations involved in the formation of the avian state. As small theropods are among the least liable to get fossilzed with full bodies, it is wonderful we have as much data as we have (and yet another indicator that the Intelligent Designer camp’s wished for Designer must really love evolutionary paleontologists, to have so presciently littered the fossil record with critters guaranteed to give them shivers of delight).

    • Mark Sturtevant
      Posted April 30, 2015 at 6:59 pm | Permalink

      Very good. I was trying to parse this out, but you did a much better job than I ever could.
      Since the styliform element is so very enlarged in this new species, I think it will be important to go back and look at other little therapods to see if they have any even slightly elongated wrist bone. It is possible that they have been overlooked.

  8. Posted April 30, 2015 at 1:57 pm | Permalink

    So there were dragons after all!

    Mre seriously, many thanks for this analysis — fascinating stuff.

    • Diane G.
      Posted May 1, 2015 at 3:08 am | Permalink

      Cool association. 🙂

  9. Kevin
    Posted April 30, 2015 at 2:05 pm | Permalink

    I just took the kids to the Denver Nature and Science museum where they have:

    http://denver.cbslocal.com/2015/03/20/mythic-creatures-denver-museum-nature-science/

    A dragon with bat-like wings. So, indeed, dragons, did exist, albeit small dragons.

  10. Posted April 30, 2015 at 2:11 pm | Permalink

    I also have no specific comment, but I want to be sure the ceiling cat knows that I appreciate science articles like this one very much!

    • Susan
      Posted April 30, 2015 at 2:32 pm | Permalink

      Ditto

    • Paul S
      Posted April 30, 2015 at 2:39 pm | Permalink

      Yes, absolutely. A very cool dinosaur. I hope they find more fossils so we get to see it complete.

    • Jim Sweeney
      Posted April 30, 2015 at 4:05 pm | Permalink

      Likewise.

    • Steve Pollard
      Posted April 30, 2015 at 4:18 pm | Permalink

      Me too. This is fascinating stuff. My only (naive) thought is that a heck of a lot of variation and selection must have gone into that sophisticated structure.

  11. Posted April 30, 2015 at 2:32 pm | Permalink

    Fuzzy birdbat wing!
    The feathers look rather primitive and not aerodynamically formed. I’d say it was most likely a glider. The muscles don’t seem strong enough for wing flapping, on the other hand, I can’t find a sternum in the fossil.
    *expletive deleted* pay wall!

    • Posted April 30, 2015 at 2:42 pm | Permalink

      Do bats have deep sterna like birds?

      /@

      • Jacques Hausser
        Posted April 30, 2015 at 3:05 pm | Permalink

        Bats have a relatively strong sternum, somewhat keeled, but nothing to compare to the avian breastbone. They are nevertheless highly efficient flyers.

      • Posted April 30, 2015 at 3:06 pm | Permalink

        No, but you need attachment points for strong muscles. In this birdbatdino I’d expect something birdlike, if he’d be able to fly actively and not just glide. Hopefully more fossils will show up, so we can find out more.

  12. Posted April 30, 2015 at 2:34 pm | Permalink

    it’s a supremely curious and yet cool dinosaur. i suspect the true complexity of their lineage has yet to unfold for us. We already know it was far from the old Social Darwinistic view of maladapted and stupid lizards, doomed to be out-competed by nineteenth century Tory voting Englishmen.

  13. Posted April 30, 2015 at 2:35 pm | Permalink

    I just showed this post to my students (high school advanced biology) and they think it is really cool.

    • Posted April 30, 2015 at 2:37 pm | Permalink

      but they were disappointed it wasn’t huge like the dragons from “Game of Thrones.”

      • Posted April 30, 2015 at 3:21 pm | Permalink

        Well…Sue couldn’t fly, but she was big and badass. Does that count…?

        b&

        • Richard Bond
          Posted May 1, 2015 at 3:57 am | Permalink

          Well, Adrian Desmond points out (chapter 6 of The Hot-Blooded Dinosaurs) that either Tyrannosaurus perched in trees or Archaeopteryx was a ground-living predator…

          • Posted May 1, 2015 at 4:21 am | Permalink

            No offense to Adrian Desmond, but his popular book was a way long time ago in paleontology circles, like talking faxes & VHS vs Beta. The arboreal vs cursorial debate still smolders a bit, but it seems increasingly irrelevant when trying to assess what small feathered maniraptoran therapods unknown in 1980s were up to. As none of the earliest birds had well-developed sternum attachments for flight muscles (that came later in the Cretaceous), many may have got airborne by jumping from a height. How much of this was done in particular groups by climbing (and their hand claws and feet arrangement made this perfectly feasible) or leaping from low escarpments after getting up to a good run is hard to say. The recent experimental modeling of Microraptor suggested they were quite capable of tree-to-tree glide and grab hold landing on trunks. Close cousins of those tyrannosaurs (now regarded as jumbo- coeleurosaurs) probably had many options for flight that these snapshots found so far only hint at.

            • Richard Bond
              Posted May 1, 2015 at 8:28 am | Permalink

              Perhaps I should have added a 🙂

      • Diana MacPherson
        Posted April 30, 2015 at 5:48 pm | Permalink

        Aside from the incorrect Greek pluralization, this is funny.

        • lkr
          Posted April 30, 2015 at 6:18 pm | Permalink

          ?Huh? Scansoriopteridae [family] and suprageneric taxa in general ARE plural, are they not?

          • Diana MacPherson
            Posted April 30, 2015 at 6:54 pm | Permalink

            It’s correct as the genitive which the family is using, but in this she seems to be referring to more than one Scansoriopteryx which would be Scansoriopteryges.

        • John Scanlon, FCD
          Posted May 1, 2015 at 6:45 am | Permalink

          Scansoriopterygidae Czerkas & Yuan, 2002 is indeed the correct name of the clade including the genera Epidendrosaurus, Epidexipteryx and now Yi. Scansoriopteryx turned out to be a junior synonym of Epidendrosaurus but the family name based on it is still valid.

          • Gregory Kusnick
            Posted May 1, 2015 at 12:04 pm | Permalink

            I think Diana’s point is that “Where is House Targaryen [the family]?” is a different question from “Where are the Targaryens [the individuals]?”

            • Diana MacPherson
              Posted May 1, 2015 at 4:41 pm | Permalink

              Yes and I think the character shouts, “where are my dragons” so the Greek word should correspond!

      • Mark Sturtevant
        Posted April 30, 2015 at 7:09 pm | Permalink

        Show them the Quetzalcoatlus
        and the terror birds.

    • Posted April 30, 2015 at 3:20 pm | Permalink

      That would seem to constitute confirmation that your students do, indeed, have a pulse. If they hadn’t found it “really cool,” I’d have been more than a bit worried….

      b&

      • Posted May 1, 2015 at 11:15 am | Permalink

        They sometimes, especially this time of year, especially the seniors, appear to lack a pulse.

        • Posted May 1, 2015 at 11:28 am | Permalink

          Oh, I know that feeling…I had senioritis from…oh, about eighth grade until…well, honestly, I probably still have at least a touch of it….

          b&

  14. Posted April 30, 2015 at 2:44 pm | Permalink

    Re pterosaurs clambering about in trees or on cliffs, modern reconstructions have them walking on all fours…

    /@

    • Posted April 30, 2015 at 2:46 pm | Permalink

      * Image: Mark Witton

    • Torbjörn Larsson, OM
      Posted April 30, 2015 at 3:09 pm | Permalink

      And launching by vaulting over a hand stance, IIRC? (Re using the “eentsy” fingers.)

      • Posted April 30, 2015 at 4:49 pm | Permalink

        I should have said, “as well”.

        Mark Witton writes; “They may, however, have spent more time running around trees and cliffs than over floodplains and tidal flats.”

        http://pterosaur.net/terrestrial_locomotion.php

        /@

      • Mark Sturtevant
        Posted April 30, 2015 at 7:10 pm | Permalink

        They would be challenged. But how else would they be on the ground?

      • reasonshark
        Posted May 1, 2015 at 4:13 am | Permalink

        The hands aren’t the important bit when it comes to vault-launching. Pterosaurs have huge upper body strength because, unlike birds, they both power their flight and takeoff with the forelimbs. A decent-sized pterosaur could takeoff from water.

        • Diane G.
          Posted May 1, 2015 at 4:18 am | Permalink

          If you find the time, would you elaborate on that a bit? I’m having trouble trying to think of how that is different from birds. Do you mean that birds are basically using their hands? (I do know how the bird skeleton is laid out, bone-wise, with the big bend where the wing folds is the wrist…)

          • reasonshark
            Posted May 1, 2015 at 4:29 am | Permalink

            I’m talking about how the animal actually gets into the air. Most birds do it by leaping/falling into the air and then flapping their wings once they’re off the ground. To do that, they use leg power to kick off, which means the ratio of leg muscle mass to arm muscle mass has to take that into account. That’s why, for instance, water fowl run across the water before flying.

            Pterosaurs can launch themselves into the air with all four limbs – basically vaulting themselves into the sky rather than kicking off the ground – meaning the front limbs play a much greater role in the launch. This is not only more energy efficient than bipedal takeoff (because the power is shared across all four limbs), but it allows much stronger muscles in the forelimbs, which also helps the actual powered flight when the pterosaur starts flapping.

            That’s why the hands aren’t actually important. Even for birds whose feet range from tiny perching claws to giant wading pads, the real power for takeoff comes from the upper leg. That’s why “eentsy” fingers don’t matter that much.

            I learned this while reading Mark Witton’s book on pterosaurs. It is truly a fascinating read; I’ll never look at pterosaurs the same way again.

            • Diane G.
              Posted May 1, 2015 at 4:55 am | Permalink

              Thank you, that makes great sense! I may have to look into that book.

              Pterosaurs did not have the “hollow” (air sac-full) bones that bird do, did they?

              I’d been noticing that the Sandhill Cranes that feed in our field are very slow to take to the air when the dogs & I come by on a walk. They’ll vocalize and start walking away, but it’s only when we get pretty close that they’ll take to the air. It occurred to me that, although they’re elegant flyers once aloft, it must be awfully hard to get that much bird off the ground in the first place. It would seem to me that on takeoff they couldn’t even do a full wing down-stroke without striking the ground! I’ll have to keep watching and try to observe that upper leg kick-off.

              I love to watch waterfowl and pelagic birds run across the water pre-liftoff!

              • reasonshark
                Posted May 1, 2015 at 5:35 am | Permalink

                Pterosaurs did not have the “hollow” (air sac-full) bones that bird do, did they?

                Oh, they did. I don’t think they have it to the same extreme degree as birds, though, and some of the earlier pterosaurs (like Dimorphodon) had more solid bones than later ones (like Quetzalcoatlus).

                I’ll have to keep watching and try to observe that upper leg kick-off.

                It’s really hard with some of the smaller birds. I’ve tried to see the kickoff with the house sparrows in the bush outside my house, but it always looks to me like they just snap straight into flight without the kick. Crows, magpies, and pigeons are much easier because they crouch right before launch, and there’s always plenty of them lurking around where I am.

                Honestly, my favourite (that I saw on TV – not lucky enough to see it up close) is seeing albatross run into the wind. That is quite a sight to behold. 🙂

              • Diane G.
                Posted May 1, 2015 at 5:45 am | Permalink

                Oh, very cool about the pterosaur bones! Another adaptation arising independently in different lineages.

                Regarding the kick-off–now that I know what to look for, I suspect it might be especially visible in Sandhills. I also have a one-legged crow that’s been around for several years; I’ll definitely have to give him some close looks!

                I took my adult son on a pelagic bird trip out of Newport, OR, last year. I’ll never forget the birds-running-on-water–especially the Brown Albatrosses, but also the shearwaters and other species. An entire realm so few of us are ever aware of.

                Thanks for the conversation and enlightenment! 🙂

              • Posted May 1, 2015 at 5:44 am | Permalink

                It is a very handsome book … I just haven’t found time to read my copy yet!

                /@

    • Pazu
      Posted May 1, 2015 at 1:55 pm | Permalink

      Probably worth pointing out that the upright quadrupedal posture is likely restricted to the more derived “pterodactyloid” forms, as opposed to the basal “rhamphorhynchoid” species.

  15. Gregory Kusnick
    Posted April 30, 2015 at 2:46 pm | Permalink

    I’m not sure I’d call this a failed experiment in flying. The fact that the styliform elements are so well developed surely indicates a considerable degree of evolutionary success; i.e. the lineage must have been positively selected for quite some time to reach that level of specialization.

    • reasonshark
      Posted May 1, 2015 at 4:15 am | Permalink

      I’m also hoping this is merely the vanguard for a whole host of discoveries. I remember my excitement, back in the day, when we went from obscure theropod claws to a whole new group of dinosaurs – Therizinosaurs.

      • Pazu
        Posted May 1, 2015 at 1:36 pm | Permalink

        Given _Yi qi_’s apparent affinities, I wonder if anyone is going to take another look at _Scansoriopteryx_ and _Epidexipteryx_ soon, especially given all the speculation over the function of the hyper-elongated 3rd digit in the former.

  16. Jacques Hausser
    Posted April 30, 2015 at 3:40 pm | Permalink

    I was extremely pleased to discover Yi qi – and I agree with Gregory: this critter was not a “failed” experiment. Even if it is known by only one fossil, it can very well have existed for a longer time than our own species. The length of the digit #4 and of the styliform element suggest actual flight rather than mere gliding. But the most important thing is that it evidences another independant evolutionary development of flying capacities among vertebrates.
    But I’m still waiting for a fossil or extant flying veretbrate like Otopteryx volitans

    • John Scanlon, FCD
      Posted May 1, 2015 at 6:50 am | Permalink

      Keep watching the Chinese Jurassic. Nothing would be surprising now.

  17. squidmaster
    Posted April 30, 2015 at 3:41 pm | Permalink

    The most unusual thing about this animal is that it’s the only one to have been found. It’s clearly quite specialized and is hardly a basal form of membranous fliers. There must be ancestral forms awaiting discovery or lying unrecognized in some museum collection. It’s also hard to imagine that there was only one species with this degree of specialized adaptation. it will be interesting to see what turns up now that folks know what to look for.

    Skin gliding (or something similar) has evolved independently several times (including in snakes), so I’m not surprised that a lineage of dinosaurs (interesting that it’s therapods again; they might have been ‘pre-adapted’) developed the ability.

    Powered flight is something else. As PCC points out, only pterosaurs, dino-birds and bats have managed that feat. If 翼奇 could fly, that would be two for dinos, three for the archosaurs and merely one for mammals.

    • Jeffery
      Posted April 30, 2015 at 4:33 pm | Permalink

      Given the odds against ANY organism being fossilized, it’s highly probable that there are literally tens of thousands of species of ancient creatures of which we will never see a single example.

    • lkr
      Posted April 30, 2015 at 7:30 pm | Permalink

      In each case where vertebrates evolved powered flight, the original airfoil seems to have been restricted to the forelimb, or at least incorporated the hand as a major portion of the control surface. Perhaps a close call to 4-limbed flight in Microraptor, but still with distal control surfaces.. Membrane gliders [numerous mammal lineages] and rib gliders [several living and extinct reptile lineages] perhaps do the original Wright Brother wing-warping for control, but still have no obvious route to controlled flapping flight

      Among extant gliders, I’d give frogs like Rhacophorus [Wallace’s flying frog] the best pre-flight model. Shame we’ll finish off the remaining anura in a century or so.

      [and here a thanks for PCC’s link to Bob Trivers’ reminisces on Tuesday — where I learn about Philip Darlin<gton's demonstration of dropping frogs off a roof at Harvard.. a less cryptic description is on the krulwich blog at npr:

  18. The Eh'theist
    Posted April 30, 2015 at 3:50 pm | Permalink

    Thank you. Much more informative than the CBC article I read this morning, especially all your comparisons with other species. I think it’s a good example to show people who don’t realize there were no “participation” trophies with natural selection.

  19. Posted April 30, 2015 at 3:59 pm | Permalink

    “… was almost certainly one of those failed experiments in flying or gliding.”

    Can someone please explain this to me? I thought I understood at least the fundamental concept of evolution but I can’t figure out how the process could conduct “experiments”, either literally or metaphorically.

    • Posted May 1, 2015 at 4:07 am | Permalink

      Nature performs experiments all the time, in the sense of variations that either do or do not lead to long-term successes, and in representing alternative modes of adaptation or novelty give a bit more or an idea of what does and doesn’t work. There is no intimation of intentionality or purpose behind this usage of experiment. The 4 winged Microraptor & this new dino-bat apparently failed to make the cut compared to the Archaeopteryx-format,. Similarly, the bipedal teetertoter tail-balancing small mammal that showed up in the Messel Lagerstatten didn’t appear to be a particularly prolific “natural experiment” either, leaving no discernable lineage.

      • reasonshark
        Posted May 1, 2015 at 5:45 am | Permalink

        Nature performs experiments all the time, in the sense of variations that either do or do not lead to long-term successes, and in representing alternative modes of adaptation or novelty give a bit more or an idea of what does and doesn’t work.

        This confuses two different things, though. It’s true natural selection whittles out unsuccessful variants within a species or gene pool, but that’s totally different from variations between species, such as Yi qi and other dinosaurs.

        In fact, it’s not even suggestive. The success of a body plan isn’t necessarily measured by how many species diversify from that plan. Extinction and species diversification are more luck-based and chaotic than natural selection, so aren’t very good indicators of how “good” or “bad” a body plan is. Besides, if a body plan “didn’t work” (in what context, by the way?), it wouldn’t evolve by natural selection in the first place.

        • Posted May 1, 2015 at 6:19 am | Permalink

          Body plans are rather far up the systematic food chain from the issue of whether a lineage succeeds or fails in the long run, and pondering why. All species eventually die out, but tetrapods are alive and well, even as no non-avian dinosaurs made the cut. Seeing the success of birds and extinction of their cousins naturally raises issues of whether it was all (not merely mainly or mostly) just stochastic crap shoot, or whether features like the ability to fly to another rock contributed to their survival while the non-fliers had to hoof it and not get munched by increasingly stressed groundlings. Short of a time machine, all we have are the broadest gathering of data and reasoned assay of it, but declaring it to be all luck seems to be assuming what it is that is supposed to be the object of the proof. The likes of Microraptor and Yi may have spawned many descendant lineages, or not. At the moment both seem highly isolated and it seems an eminently appropriate paleontological topic to wonder whether the reason for that turned on their particular adaptations proving less fertile in staking out niches that were successful over the long haul.

          • reasonshark
            Posted May 1, 2015 at 9:31 am | Permalink

            My point is that describing Yi or Microraptor as “failed experiments” but Archaeopteryx as a “successful experiment” – based on whether they diversify or not, for instance – is an unhelpful metaphor at best, and a positively misleading one at worst. This isn’t about whether extinctions follow certain patterns or not.

            Compared with the logic of natural selection, they are luck-based. We’re talking about adaptations. Adaptations arise in lineages to increase individual chances of survival and reproduction, ultimately to propagate genes. They don’t arise to pit species against species, much less whole taxonomic groups against taxonomic groups.

            For one thing, it’s snobbishly judgemental in the Victorian “extinct animals are inferior animals” sense, born almost entirely from hindsight and a vague concept like “success” which is meaningless in context. Pterosaurs, for instance, were incredibly efficient flying organisms, but it’s best to explain that via the natural selection of aerodynamic bodies with modified limbs and mechanical factors, not by talking as if reptiles fancied to try their luck in their air as an “experiment” and entered competitions against birds.

            For another, the example you cite is transparently luck-based. An adaptation is already in place in your hypothetical scenario comparing flyers against grounded cousins, and since the deciding factor is environmental, from an evolutionary perspective it IS luck-based. There was no way the evolution of the wings was somehow deliberately aiming to prepare for or test models against the sudden environmental change, so the fact that it fits is simply lucky. It’s not that the traits are irrelevant, of course, but you only need to invoke histories and physical-mechanical aspects to explain this, not some metaphorical evolutionary experimentation.

            Lastly, again you’re confusing different issues. That certain adaptations could translate well when thrust into another environment compared with others, and that this is a valid topic of palaeontological study, is not the issue. The issue is describing evolution as if it “experimented”, which apart from the teleological implication, mischaracterizes the above-mentioned topics.

            Dr. I. Needtob Athe is right. Evolution doesn’t conduct experiments, metaphorical or literal, so describing an extinct species as a “failed experiment” is either meaningless or a gross misunderstanding of how evolution works.

            • Posted May 1, 2015 at 5:41 pm | Permalink

              I don’t see teleological implications in the differential success of the natural experiments that you do not perecive to be natural experiments at all, so how much “gross misunderstanding” is going on here (as opposed to definitional frames) I’ll leave to others to assess. It seems we’re treading on a deep conceptual gulf though, much as Alfred Wallace just wouldn’t budge on not seeing the analogies of artificial selection with natural selection that Darwin thought so apparent.

            • Diane G.
              Posted May 3, 2015 at 3:35 am | Permalink

              I think you’re overthinking it. I easily see a metaphor in that each variation that comes about through mutation and whatever other ways can be thought of as an experiment–an experiment in how well that variation survives in a given environment. Have more than one variant and natural selection favors one or more variants that produce the most surviving offspring. The variants that can’t keep up, or survive a change in the environment were essentially failed experiments–“nature tried them but they didn’t work.”

              I think people can easily grasp the use of teleological wording to describe processes like these, just as they understand, “the water wants to flow downhill,” or “the seed wants to land in an area conducive to germination.” Thinking they can’t is another sort of “little people” argument, and at worse can result in very opaque writing or speaking when trying to avoid it.

              • Posted May 3, 2015 at 2:28 pm | Permalink

                I worry, though, because that kind of metaphorical teleology is often concretised by creationists and their ilk.

                /@

              • Posted May 3, 2015 at 4:17 pm | Permalink

                Don’t worry so much on that front, as absolutely everything anyone can say can (and usually has been) parsed & filtered & quote-mined by antievolutionists to serve their apologetic purpose (I keep track of this sort of thing in my new #TIP project at http://www.tortucan.wordpress.com, such as TIP 1.3 on the Punctuated Equilibrium case). Some statements made by scientists are more easily mined than others, of course, but trying to second-guess the antievolutionist radar is a thankless & futile task, better just to stick with assessing the fullest range of relevant data as best one can and let the apologists parse as they will.

              • Diane G.
                Posted May 4, 2015 at 4:41 am | Permalink

                Well of course one has to qualify one’s audience. But when I see biologists telling biologists that they’re being too teleological, I just want to tell them to get off their friggin’ high horse.

                Nor do I think we need to worry about the WEIT audience. With any luck at all.

                Metaphors exist for a reason. We like them, and they can be suitable shorthand.

                (And the creobots are going to twist whatever we say, anyway. A lot of them are being dumb as foxes.)

  20. Posted April 30, 2015 at 5:27 pm | Permalink

    Cool. Thanks for the comparisons to pterosaurs and bats.

  21. Diana MacPherson
    Posted April 30, 2015 at 5:41 pm | Permalink

    “…it’s missing the rear bits, including the crucial tail…” God is always teasing us.

  22. Mark Sturtevant
    Posted April 30, 2015 at 6:13 pm | Permalink

    Holy crap. I leave for a few hours, and a really cool post comes up. I gotta just keep my laptop with me at all times, I guess.

    • Gregory Kusnick
      Posted April 30, 2015 at 6:32 pm | Permalink

      Or your phone.

      • Mark Sturtevant
        Posted April 30, 2015 at 7:13 pm | Permalink

        posting in WEIT from my phone is a pain. At least I cannot get it to remember me from Safari so each time I need to enter my name and e-mail, etc.

        • Diana MacPherson
          Posted April 30, 2015 at 7:19 pm | Permalink

          Force your phone to give you the desktop site if you aren’t getting that one.

          • Mark Sturtevant
            Posted April 30, 2015 at 11:26 pm | Permalink

            I have google desktop on my iphone, and even if I log into my gmail there, in WEIT I still have to enter my gmail email and pw in WEIT.

          • Mark Sturtevant
            Posted April 30, 2015 at 11:44 pm | Permalink

            Having looked into this more, I think it is a keychain access feature that I need to work on in Safari. I need to put this site into my keychain and tell Safari to use it. We will see.

            • Diana MacPherson
              Posted May 1, 2015 at 11:02 am | Permalink

              That sounds about right.

        • Posted May 1, 2015 at 1:36 am | Permalink

          Do yo not have a WordPress account?

          /@

      • Posted May 1, 2015 at 1:33 am | Permalink

        “Phone” seems so inadequate to describe the device we now have.

        It’s more a personal handheld for online networked entertainment. If only there were a good acronym for that …

        /@

        • HaggisForBrains
          Posted May 1, 2015 at 4:36 am | Permalink

          😀

  23. Marella
    Posted April 30, 2015 at 6:48 pm | Permalink

    Fascinating; this opens a whole new sphere of dinosaur possibilities. It doesn’t look to me as though it had the right proportions for actual flight, but who knows, and it was certainly well on the way. Maybe its descendants could have done it even if it couldn’t.

    • Gregory Kusnick
      Posted April 30, 2015 at 8:01 pm | Permalink

      From the scale bar, it looks like this dino was maybe about the size of a large jay or small crow, so the proportions aren’t too far out of whack for a flying creature of that size.

      • Marella
        Posted April 30, 2015 at 11:25 pm | Permalink

        Oops, I didn’t notice that, I thought it was more chicken sized. Even more awesome then.

  24. Posted April 30, 2015 at 7:55 pm | Permalink

    Thanks A LOT. This is fascinating. I envy scientists who can learn so much from so little.
    My daughter and I are equally excited about dinosaurs, so it’s going to be fun talking to her about this.

  25. Shwell Thanskh
    Posted April 30, 2015 at 11:12 pm | Permalink

    What an approachably worded, patient explanation! Thank you, Professor.

  26. Nick
    Posted May 1, 2015 at 2:16 am | Permalink

    Thanks for posting this, Jerry

  27. Diane G.
    Posted May 1, 2015 at 3:28 am | Permalink

    Evolution rocks!

  28. Steven in Tokyo
    Posted May 1, 2015 at 5:11 am | Permalink

    Very interesting post. Many thanks.
    One quibble about the new scientific name. It’s very opaque, isn’t it? Without the Chinese characters, how is one to tell that Yi qi means ‘strange wing’? There are more than 100 characters pronounced Yi in my (rather ordinary) Chinese-English dictionary, and more than 60 pronounced qi. That gives an awful lot of combinations. At least with Latin-derived names we have a chance of working out what they mean by ourselves …

    • John Scanlon, FCD
      Posted May 1, 2015 at 7:00 am | Permalink

      Scientific names have been devised using words from hundreds of different languages apart from Latin so nobody expects the etymology to be transparent, which is why it’s nearly always (these days) explained in the paper.
      I knew a girl at uni whose Chinese given name was Yi-Chi (because she was born on Chicago). I doubt whether I could detect a phonetic difference between her name and this new dinosaur’s, but I know they mean different things because she didn’t look anything like a Skeksis.

      • Steven in Tokyo
        Posted May 1, 2015 at 9:26 am | Permalink

        Born on Chicago. She must have been big.

        • John Scanlon, FCD
          Posted May 1, 2015 at 9:36 am | Permalink

          – in – 🙂

    • Posted May 1, 2015 at 11:40 am | Permalink

      Apparently sometimes people use numerals, though I am not sure I’ve seen them outside a dictionary. So this might be (e.g.) yi2 chi3.

  29. StephaJL
    Posted May 1, 2015 at 6:52 am | Permalink

    I don’t have much to contribute to this discussion, but it is fascinating, nonetheless. Thank you for posting it.

    The colouration in the imaginative reconstruction is interesting. I am aware that some research has established (or strongly suggested) that at least a proportion of dinosaurs sported brightly-hued feathers or crests. Out of curiosity, where does this specimen fit in that timeline? Might it have been brightly coloured? Have we learned or inferred anything about the appearance of its closest relatives that might shed light on its appearance?

  30. mlm
    Posted May 1, 2015 at 7:42 am | Permalink

    Thanks for posting. Love this kind of stuff, with the comparative anatomy and whatnot.

    I googled, but didn’t find a definitive answer. Can anyone say how many species are known by only one specimen? I’m sure it’s a good fraction. Thanks!

  31. Posted May 1, 2015 at 9:39 am | Permalink

    I wonder if some kind and knowledgeable reader might be able to point us in the direction of a piece, or pieces, describing the different evolutionary paths of flight/gliding?

    • Posted May 1, 2015 at 6:01 pm | Permalink

      I’m aware of a few big picture reviews, starting with a work on the biological dynamics of controlled arboreal falling that may have played a part in all vertebrate flyers. Dudley, Robert, Greg Byrnes, Stephen P. Yanoviak, Brendan Borrell, Rafe M. Brown, & Jimmy A. McGuire. 2007. “Gliding and the Functional Origins of Flight: Biomechanical Novelty or Necessity?” Annual Review of Ecology, Evolution and Systematics 38: 179-201.

      That the avian flying capacity built on prexisting anatomical range discussed in Nudds, Robert L., & Gareth J. Dyke. 2009. “Forelimb Posture in Dinosaurs and the Evolution of the Avian Flapping Flight-Stroke.” Evolution 63 (April): 994-1002.

      For the possible role avian feet played in the stability of perching and take-offs, Kurochkin, E. N., & I. A. Bogdanovich. 2010. “Origin of Feathered Flight.” Paleontological Journal 44 (December): 1570-1588.

      And then there’s Dececchi, T. Alexander, & Hans C. E. Larsson. 2011. “Assessing Arboreal Adaptations of Bird Antecedents: Testing the Ecological Setting of the Origin of the Avian Flight Stroke.” PLoS ONE (online @ plosone.org) 6 (August): e22292.

  32. gravelinspector-Aidan
    Posted May 1, 2015 at 2:39 pm | Permalink

    There’s an analysis of the phylogeny of this specimen, but that needn’t detain us here; suffice it to say that it nests within the other theropod dinosaurs, and so is not at all a pterosaur.

    Look at the skull. Diapsid (two windows in the skull – and a spare!) with a mandibular fenestra (“window” – as in Prague). Not quite definitive of a dinosaur (you need the ankle and femoral socket to nail it down), but by the time you’ve seen those, you’re close enough to “dinosaur” for non-specialists.
    It’s a cool find, but the link to the paper isn’t free. I’ll try to snarf it off the work’s connection tomorrow – I think they have a site license to Nature.

  33. Posted May 2, 2015 at 9:14 am | Permalink

    Reblogged this on My Selfish Gene.

  34. Posted May 10, 2015 at 9:23 pm | Permalink

    Fascinating creature.

  35. Posted May 22, 2015 at 5:20 pm | Permalink

    It is a great transitional between pterosaur and primitive bird.


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