New fossils: the world’s earliest known bird

May 8, 2015 • 11:15 am

Here’s a short scientific report (yesterday’s didn’t inspire much enthusiasm)—short because much of the paleontology is beyond my expertise, as the paper consists largely of describing features I’m not familiar with. But this new paper in Nature by Min Wang et al. (link and reference below) is quite important, for it describes what appears to be the earliest true bird: two specimens of a species found in China in the early Cretaceous (130.7 million year old). And it pushes the origin of the ancestor of modern birds back at least five million years.

Based on its features, this bird, named Archaeornithura meemannae, falls within the group “Ornithuromorpha,” which includes all modern birds and their common ancestor, as well as all the extinct descendants of that ancestor. It can thus be regarded as a “bird,” and its well-preserved plumage suggests that it not only could fly, but was close to the appearance of modern birds.

I’m going to let the readers, some of whom really know this stuff, apprise us all of its further significance, as well as correct any errors I make.

Here is one of the two fossils, showing the plumage and wings. It was about the size of a sparrow. The main slab is to the left, the counter slab to the right (these are the two halves of a “compression fossil” found in sedimentary rock, obtained when you split the rock to get the fossil itself):

(From paper): Figure 1 | Holotype of Archaeornithura meemannae gen. et sp. nov., STM7-145. (a) Main slab; (b) counter slab. Anatomical abbreviations: al, alular digit; ba, basicranium; co, coracoid; cv, cervical vertebrae; d I–IV, pedal digit I–IV; fe, femur; fi, fibula; fu, furcula; hu, humerus; ma, major digit; mi, minor digit; pr, primary remiges; pu, pubis; ra, radius; re, rectrices; sc, scapula; st, sternum; ti, tibiotarsus; tm, tarsometatarsus; ul, ulna. Scale bars, 10 mm.

Below are the wingbones of the same specimen (aren’t they cool?), and its very birdlike feet:

Screen Shot 2015-05-08 at 10.30.30 AM
(From paper) Figure 3 | Detail anatomy of Archaeornithura meemannae gen. et sp. nov. (a) Photograph and (b) line drawing of the left wing, STM7-145, counter slab; (c) line drawing of hands of other hongshanornithids (not scaled; from left): Hongshanornis longicresta, Longicrusavis houi, Tianyuornis cheni, Parahongshanornis chaoyangensis; (d) STM7-163, counter slab; (e) STM7-163, main slab; (f) feet, STM7-163, main slab. Anatomical abbreviations: al, alular digit; am, alular metacarpal; ca, caudal vertebrae (six vertebrae counted); del, deltopectoral crest; d I–IV, pedal digit I–IV; hu, humerus; is, ischium; ma, major digit; mam, major metacarpal; mi, minor digit; mim, minor metacarpal; mt I, metatarsal I; pb, pubic boot; pu, pubis; py, pygostyle; ra, radius; sp, supracondylar process; ti, tibiotarsus; tm, tarsometatarsus; ul, ulna. Scale bars, 10 mm (a,f), 5 mm (d,e).

Finally, the plumage and feet of the second specimen. The preservation is quite amazing:

Screen Shot 2015-05-08 at 10.32.40 AM
(From paper): Figure 4 | Plumage of Archaeornithura meemannae gen. et sp. nov. (a) Left wing, STM-7-145, main slab; (b) right wing, STM-7-145, main slab; (c) covert feathers over the skull and neck, STM 7-163, counter slab; (d) alular feathers on the left alular digit, STM7-163, main slab. Abbreviations: af, alular feather; dc, dorsal coverts; pr, primary remiges; re, rectrices. Scale bars, 10 mm (a–c), 5 mm (d).

A few points. First, the “flight” feathers are symmetrical. That used to be a sign that the bird couldn’t fly, as asymmetrical feathers (with the leading edge about half the width of the trailing edge) are present in modern flying birds. But apparently asymmetry is no longer seen as a sign of flightlessness.

Second the bird had a head crest (see reconstruction below).

Third, it had two other features suggesting it could fly. The first is “fan-shaped retrices”, or tail feathers. This shape helps provide lift to a flying bird. It also had an “alula“, also called a “bastard wing”: a group of feathers associated with the mobile first digit of the bird, and present in some modern birds, where it can help the flying animal slow down without stalling.

Here’s a graphic of an alula (in red), and a photo of it extended in action, helping an eagle land (both from Wikipedia). I believe the alula in the eagle picture is the clump of four feathers sticking up on the far wing.



As the authors note:

Archaeornithura preserves fairly advanced plumage including a well-developed alula and fan-shaped rectrices (Figs 1 and 4. . ). Both the alula (bastard wing) and a fan- shaped tail are aerodynamically important for living birds during slow flight and increases manoeuvrability.

Finally, here’s a reconstruction of A. meemannae from the Cosmos site. That’s a damn bird!

[Credit: Zongda Zhang]

Wang, N. et al., 2015. The oldest record of ornithuromorpha from the early cretaceous of China. Nature Communications 6, Article number:6987doi:10.1038/ncomms7987

95 thoughts on “New fossils: the world’s earliest known bird

    1. Yes; why is this?

      Is it something to do with the geology; do the sedimentary rocks have a finer granularity than those elsewhere? Or are the fossils somehow subject to less degradation (less seismic activity?)?

      Or is it somehow that paleontological techniques have improved?


      1. I found this on the national geo site. Interesting, as I was wondering the same thing about the abundance of fossils coming out of China.

        Some scientists call Liaoning a Mesozoic Pompeii, evoking the ancient Roman city where humans were entombed by the eruption of Mount Vesuvius. But in its own way Liaoning is even more remarkable. Repeated volcanic eruptions created a layer cake of fossil beds spanning millions of years. So far, more than 60 species of plants, nearly 90 species of vertebrates, and about 300 species of invertebrates have been identified. Paleontologists marveled at dinosaur fossils with stomach contents identifiable as the bones of lizards and mammals, and at bird fossils containing plant seeds.

        Liaoning is situated within a vast region whose primeval flora and fauna are referred to as the Jehol biota. The area was characterized by a warm climate and numerous lakes. These conditions provided a fruitful environment for plants and animals to differentiate and nourish. So many individual fossils have been found that scientists are able to study population dynamics, succession within communities of interacting species, and even predator-prey relationships.

        1. This seems to be from a kind of ‘Lagerstatten which is a rich fossil bed that preserves a rich biota of species not otherwise seen.

  1. This is way cool. But I do not see that the flight feathers are symmetrical. The primary fight feathers (attached to the hand) seem asymmetrical in the fossil and in the reconstruction. The more proximal ones along the wrist and forearm may be symmetrical, however.

    I bet they can reconstruct a pigment pattern off of this beautiful fossil.

    1. So by symmetrical here we mean that primaries and secondaries (and even tertials?) are the same length, essentially?

      1. I understood symmetrical to refer to the width on either side of the rib (rachis) running the length of the feather. For flight feathers there would be a leading and trailing edge.
        Check out Wikipedia/Feather/Evolutionary stages.

        1. Oh, duh! I know this. For some reason that asymmetry was eluding me, thus the extremely dumb question. (Which I didn’t think was the case anyway.) Jerry even spelled it out; must quit skimming.

  2. You wrote, “yesterday’s [science post] didn’t inspire much enthusiasm”. The kin selection post? I read it. I enjoyed it and chuckled at some parts. I didn’t have anything to add (and I was supposed to be working). I like the science posts and hope you keep them coming!

      1. Yes, I just finished reading it not long ago and thought the discussion was quite avid and lengthy.

  3. This is fascinating stuff and that is one punk-rock looking bird there in that rendering.
    I’m curious, is the alula digit at all like first finger on a bat’s wing? And, if so, does that mean that bats and birds developed their wings along similar lines?
    These posts are so great, I learn stuff by accident. I’m still trying to wrap my head around the whole pterosaurs are not dinosaurs thing.

    1. There are some significant differences between bat wings and bird wings, though in general they do seem remarkably similar for being the results of two different evolutionary histories. Or, maybe not. Much of their evolutionary history is shared. They are both four limbed vertebrates after all.

      In any case check out this article by Jerry from a week or so ago.

      Dino-bat: a new flying dinosaur with membranous wings

      It contains some good information on the differences between the wings of pterosaurs, birds, bats and the newly discovered winged dinosaurs that the article is about. There is also additional good information in some of the comments.

              1. Don’t put your pedestrian pedant wearing a pendulous pedicellate pendant at a pageant on a pedestal. He has a predilection for pedicating pedlars in need of pedicures. Or worse.


    2. It looks to me like the 1st finger of a bat wing is just for holding on to a perch. Their 2nd finger (which runs along much of the leading edge) might serve as the alula. But I do not know if that is so.

  4. So it seems that for roughly 60 million years, from 130 to 65 MYA, there were both pteradactyls and other flying reptiles and birds up in the air, even if the former still dominated the skies until the massive extinction event that left birds the sole flying vertebrates, at least until bats evolved 52 million or more years ago.

    1. Perhaps for powered flight, but gliders may have gone back further. The problem is that the fossil record of bats pretty much sucks. The oldest fossil bats are already close to modern bats, so I do not think we know how far back they go.

    2. Yeah, I looked up what the fauna was in the Cretaceous and was surprised to find these birds lived among the dinosaurs. That leads me to believe that there are even earlier birds than this.

  5. That is a marvelous fossil! Slowly we are increasing the resolution of our picture of the history of life.

  6. “It also had an “alula“, also called a “bastard wing”: a group of feathers associated with the mobile first digit of the bird, and present in some modern birds, where it can help the flying animal slow down without stalling.

    Here’s a graphic of an alula (in red), and a photo of it extended in action, helping an eagle land (both from Wikipedia). I believe the alula in the eagle picture is the clump of four feathers sticking up on the far wing.”

    Yes, it would act like a wing leading edge slat (usually gapped in landing configuration) or like a vane. The vane serves to create a strong vortex and the vortex wraps back over the wing and pulls “high energy” air flow onto the wing upper surface which retards flow separation over the wing (which is what stalling is).

    This page shows both a slotted LE slat and a series of “VGs”: small “vortex generators” (or vanes written small):

    This page shows a large vane on a nacelle, which performs the same function for the wing. If you scroll down, you can see the vortex itself by the condensation it causes:

    Here is more from the Wikiness:

    People are putting them on cars too:

    Generally, VGs are considered “aerodynamic bandaids” to save an airplane from bad stalling characteristics.

    I guess nature gets a pass on that! 🙂

  7. But this new paper in Nature by Min Wang et al. (link and reference below) is quite important, for it describes what appears to be the earliest true bird:

    I’m not sure why you’d say that, because it seems to me to be either incorrect or poorly worded. For starters, genetic studies suggest that the “true bird” – that is, I’m assuming you mean the most plausible and recent common ancestor of all extant birds that is itself a bird – arose roughly 119 million years ago, which is about 10 million years later than the provenance of Archaeornithura meemannae. Source:

    Secondly, there’s nothing particularly special about the taxon Ornithomuromorpha. The last “traditional” dinosaur group was – depending on which members you consider “traditional” – either the Troodontidae or the Archaeopterygidae. There are a few levels of evolutionary taxa between them and Ornithomuromorpha, in which more bird-like features become progressively more prominent. And there are a few levels between Ornithomuromorpha and true birds, which continue the trend.

    Each stage brought its own “step” on the evolutionary line towards modern birds – for instance, the short-tailed form that we recognize as more bird-like than dinosaur-like became a distinguishing feature of the Pygostylia, which came soon after the Archaeopterygidae but a good time before Ornithomuromorpha. Yet, many birds still had teeth right up to Ichthyornis, which was a basal member of Carinatae, which in turn is probably the last major taxon (or one of the last major taxa) that you’d encounter on the current family tree before you hit true birds proper.

    Thirdly, I don’t see the linked article mention anywhere that it was “the earliest true bird” or anything of the sort. It does point out that A. meemannae is the oldest Ornithomuromorphan yet found, which pushes the establishment of this group back a good way, but it would be pretty arbitrary to say this is the same thing as finding the first true bird. Not least of all because it depends on what you’d define as “the first true bird”.

    Don’t get me wrong: it’s a cool find. The level of preservation alone is spectacular, and I’m not surprised it comes from the rich deposits of China. It’s just not as exciting as “the first true bird”! n_n

    1. Perhaps one should read it as ‘the earliest known true bird since a fossil provides a definite time stamp of the past but genetic clocks, especially those that stretch back 10s of millions of years, can only be estimates with more significant error bars and different conclusions based on what DNA is used and how it is used. The source you cite for example (which is interesting!) has a range of estimates based on this or that genetic study of modern birds. Some put the last common ancestor of modern birds over 130 mya, right in the midst of this fossil.
      I do not presume to know what a ‘true bird’ should be, especially since Archaeopteryx is often described as the ‘1st bird’ (so what is a true bird?). Perhaps a true bird is one that bears the full range of modern features like short tail, no teeth, a beak, reversed toe, etc. etc.

      1. Two points: first, “true bird” is not a well-defined, taxonomic concept and has no agreed-upon meaning.

        Second, all those dates for bird taxa on Time-trees have problems and the error bars should be huge. But the dates are for a particular node, modern birds, often called Neornithes, which this fossil apparently is not, quite. So it would not be surprising to find it older than the first modern bird.

    1. I think that the cases where color patterns of fossil dino/bird feathers were determined were by seeing the different sizes of pigment granules which can be preserved in fine sediments. So those are pigments, but they too have a structural side since they are (were) contained in tiny granules.

    2. Structural colors, such as the blues and iridescence, of feathers are based on patterns of light refraction/reflection, so I’m not sure whether they could be discerned from fossils. Feather colors from pigments such as the melanins or porphyrins might be easier to determine.

      I remember seeing an elaborate book on iridescence as a child, when I was taking drawing classes from a local artist. Wonder if I could find that book somewhere … one can find anything on the internetz, right? 😉

      1. I’m sure I wouldn’t be able to find the link, but I know there’s been some research published relatively recently about electron micrographs of fossilized feathers that preserved enough detail for the researchers to reverse engineer their likely appearance. I’m wondering if there’s enough left of these fossils for something similar….


        1. Maybe if there was enough detail from the fossils, a 3D printer could be used to recreate the feathers, and experiments with light reflection might be possible.

          Too wacky???

          1. Too wacky? Not at all. Why, with the right adjustments, the pulse of energy from a lighting bolt might just bring such a model to life! Archaeornithura meemannae flies once again to the highest parapets of the castle. 😎

          2. Not necessary…and I don’t think 3D printing has anywhere near that kind of resolution.

            The math is actually extremely straightforward; the diffraction grating equation is just simple multiplication / division.

            …but it would be cool were it possible….


  8. But apparently asymmetry is no longer seen as a sign of flightlessness.

    I think you mean “symmetry” here.

  9. I can already see the creationist arguments. “Birds have not changed in 130 million years!”

    1. And they would be wrong. This bird is an adult with that seems to still have little claws on its fingers.

  10. Should there be any concern regarding the dating? The specimens were obtained from a dealer who then showed the authors the stratum from which it purportedly was taken. The authors then basically assert that all visible characteristics of the matrix around the the specimens match the rocks at that location. I wonder if other tests on the matrix could further confirm that conclusion.

  11. This fossil is incredibly well preserved! I’m going to have to go and review the phylogeny of birds again. but, correct me if I’m wrong, ornithomuroporpha is the sister taxon of enantiornithes, no? Does this find push back the likely date of differentiation of theropods into birdierlike forms or merely flesh out the variety in avian populations in the early cretaceous?

    1. The paper is open access, follow the link. Enantiornithes and Ornithuromorpha are indeed sister taxa (see Fig. 5). Because there are already some enantis (Protopteryx, Eopengornis) thought to be slightly about the same age or slightly older than Archaeornithura it won’t have far-reaching implications for the age of even deeper branching events (e.g. involving dromaeosaur-like taxa like Archy), but means that all the ornithuromorph branches basal to the new species have a ‘hard’ minimum age.

  12. This looks like a pretty “advanced” bird. Are we approaching the point where we say that birds and dinos evolved from a common ancestor, rather than saying birds are dinosaurs or that birds evolved from dinosaurs?

    1. Only Alan Feduccia says that birds and dinos share a common ancestor. The overwhelming evidence is that birds are descendants of a particular group of bipedal carnivorous dinosaurs. These dinos probably had a number of characteristics seen today in birds, namely hollow bones containing air sacs that connect to the lungs (which is a very strange feature also seen in some other reptiles), 3 digits on the hand and 4 digits on the feet, a mobile upper jaw, a ball and socket joint at the back of the skull, and of course feathers.

      1. Of what use were the hollow bones to the bipedal (pre-bird) dinosaurs? Were they already flying?

          1. So–it arose in this clade pre-flight so was a preadaptation, as we used to say, to flight. How cool!

        1. As far as I know, they housed air sacs that exposed inhalations to a larger surface area, allowing more efficient gas exchange and increasing the energy-efficiency of each breath. That would certainly help an active hunter like your traditional Tyrannosaurus rex.

          It’s also likely to have been an economical way of achieving great size without compromising bone strength, as sauropods like Brachiosaurus altithorax had similar structures in their massive bones.

  13. Fascinating. 160 million years and not much change. At least at this gross level.
    If I let my imagination soar like a bird, I can see myself walking through a cretaceous forest seeing this pair flitting about chasing bugs and feeling right at home.

  14. I rarely comment on science posts as I don’t know enough to make anything approaching an intelligent comment.

    Like the others I was amazed by the level of preservation. I would not normally have mentioned that, as I have no idea whether the quality is rare or not. However, from the other comments, it seems it is.

    Please keep this type of post coming – they’re fascinating.

  15. Oh damn. Another “earliest bird” and I missed it.
    no big deal. There will be another along any month now.

  16. Awesome fossil – and an awesome insight into the deeper patterns of evolution, which continue to unfold as we discover more. I am intrigued about the number of times our vision of ‘dinosaurs’, ‘birds’ and so forth has been turned over by new discoveries, dismissing old certainties and raising many new questions, but also often making ‘problems’or ‘paradoxes’ go away. I think as we find more fossils, we’ll get a better picture – my suspicion is that the specialisation shown in birds emerged from dinosaurs earlier, and perhaps more broadly, than we imagine.

    I suspect one of the biggest problems in visioning all of this has been the nineteenth century supposition, still implicit in the popular view, of evolution as ‘directional advance/improvement’ rather than ‘change through time’.

    To me, all of it offers a lesson in the human tendency to rationalise and find patterns even where the evidence is incomplete – a product of the age of reason that has led us down various blind scientific paths and provoked many bitter debates, frequently pivoting around ego and status rather than any effort to find the abstract truth. The issue doesn’t just affect science.

    Meanwhile, I have to go. There are some ex-dinosaurs lined up outside (Passeridae and a few Sturnidae, in this case) that want their lunch.

  17. the group “Ornithuromorpha,” which includes all modern birds and their common ancestor, as well as all the extinct descendants of that ancestor.

    I had not been previously acquainted with “Ornithuromorpha”, but the definition you provide here corresponds to a group known either as Neornithes or Aves, depending on which you like. It would distress me to find a third synonym.

    According to Wikipedia, though, that isn’t the definition, this is: “the common ancestor of Patagopteryx, Vorona, and Ornithurae, plus all of its descendants”. Ornithurae in turn is “the common ancestor of Hesperornis and Neornithes, plus all of its descendants”.

    This is all very picky, but that’s taxonomy for you. I infer that this new fossil is considered a member of Ornithurae that isn’t a member of Neornithes, i.e. at least a couple of nodes removed from the last common ancestor of modern birds.

    1. OK, I was wrong about its location. According to the phylogenetic analysis in the paper, Archaeornithura is within Ornithuromorpha but outside Ornithurae.

      I see the skull isn’t well preserved, but it’s reconstructed as lacking teeth. But several toothed birds, including Hesperornis and Ichthyornis are closer to modern birds. So either the reconstruction is faulty or this is another evolution of toothlessness. Neither is particularly unlikely.

  18. I don’t comment on the scientific posts because I don’t have the proper credentials. (Snicker)

    Please know, PCC, that I keep coming back to your website for the science. The politics and atheism is good too but there are lots of other places for that. Not so much the science. I got so little good science in my formal schooling.

  19. Will someone please invent a Time Machine, suitably armoured of course, that will go back to the Cretaceous and beyond so that we can observe all the glorious wildlife that is lost to

    1. Sure. Let’s see…I have some quantum oscillators and dilithium crystals around here somewhere…
      You want the seats fabric or Naugahyde?

        1. So much to do…so little time. Hand me that ultrasonic screwdriver and stand back out of the way.

  20. Amazing. The preserved detail is incredible. I didn’t know about the alula before; that’s a pretty cool appendage.

  21. What a beautiful fossi! I can’t wait to share this news with every evolution denier I can find.

  22. Anyone know what methods they used to date it, and what the error margins are? It always amazes me how precise we can get these ages to. (4 significant digits!)

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