Wednesday, May 25, 2011

The Ashdown Maniraptoran

As you may have heard by now, Darren Naish and Steve Sweetman have described an incredibly small, yet apparently adult, cervical vertebra of a maniraptoran dinosaur from the Wadhurst Clay Formation. My first reaction upon seeing pictures of this nice little water-polished bone was "that is effing adorable," followed by "I need to restore this despite the fact that we can have no clue what it looked like." So I did, and the result is shown above (and on my deviantArt page). Let me emphasize again: this is a *highly speculative* restoration of the so-called Ashdown maniraptoran. Darren did a great job of discussing the new paper at TetZoo, so I won't go into details here.

While it is entirely speculative, based as it is on a single bone, it is possible to make some educated guesses about life appearance. Naish and Sweetman note several characteristics of the vertebra that are similar to oviraptorosaurs. However, it is from the early Valenginian age, about 140 million years ago. This is nearly 20 million years earlier than the oldest known definitive oviraptorosaurs, Caudipteryx and Protarchaeopterx. So, I essentially restored this as a very small protarchaeopterygid-grade animal, hence the short tail and tightly-folding wing feathers (oviraptorids could fold their wings more tightly than even many early birds).

There is also some influence from scansoripterygids, given its small size (and as a slight nod to GSP's interpretation of Epidexipteryx hui as a basal oviraptorosaur). Naish and Sweetman point out that the large neural canal of the vertebra is a characteristic of Avialae, but that it may also be a more general size-related character. The scansor influence is found mainly in the shape of the skull and the large procumbant teeth, but those these are the characteristics which are shared by early oviraptorosaurs anyway, and so allow extra wiggle room should it turn out to be closer to avialans. I made the legs quite long compared to the ratio seen in its larger possible relatives, and made the foot fairly large (to better emphasize the diminutive size). The longer legs would, I reckon, help escape hungry mammals, lizards, and whatever else was preying on tiny maniraptors.

Finally, the coloration is fairly drab and cryptic (inspired by small modern birds that spend time hiding in undergrowth) and I chose yellow hues to indicate a bit of an omnivorous diet.

So, while it's impossible to accurately depict an animal based on a single bone which we have trouble even assigning to any specific clade, using some knowledge of basal maniraptoran lineages (it is almost certainly a fairly basal member of whichever clade it belongs to, given its early age), we can make some pretty reasonable (I hope!) guesses.

* Naish, D., and Sweetman, S.C. (2011). "A tiny maniraptoran dinosaur in the Lower Cretaceous Hastings Group: evidence from a new vertebrate-bearing locality in south-east England." Cretaceous Research, 32: 464-471.


  1. This is win. Goes to show that we can still make a reasonable (albeit highly speculative) reconstruction from scrappy remains.

  2. What do we know about non-avian dinosaurs and wing folding? This is the first time I've seen a non-avian dinosaur reconstructed as folding its wings the same way a modern bird does and I'm curious to learn more.

  3. @Anonymous In general, it seems that most basal maniraptorans could not fold their wings to the same extent as modern birds. This is a bit odd considering that they did have large wings, and obviously need to keep their long feathers from dragging on the ground. Sullivan et al. showed that in a 'normal' bird-like (or other theropod-like) posture Microraptor's wings would have collided squarely with the ground, because it could not fold its wrist enough to keep them up and back (the wrist could bend backward at an angle of about 60 degrees relative to the ulna). He suggested that they may have solved this by *not* folding at the *elbow* and sweeping back the entire arm. Diagrams are provided here:

    The exception to this seems to have been oviraptorosaurs. In Caudipteryx, which is a fairly basal member of that group, the wrist could be folded back 76 degrees (more than the modern turkey). Given the supposed oviraptorosaur affinities of this new specimen, I gave it tightly folding wings as well.

    Relevant paper:

  4. Your reconstruction looks shorter-necked than the silhouette reconstruction on Tetrapod Zoology, which is kind of funny considering the only known element. Is this simply a postural difference? Could a non-avialan maniraptor curl its neck as tightly as a modern bird?

  5. @Brad: Yeah, it's a posture thing. I actually used that skeletal directly for this recon (Darren alerted me to his TetZoo post on Twitter as I was beginning to work on this, in time to take it into account), but the neck in the skeletal is completely outstretched which doesn't seem like a very natural position for just sitting there. The neck wouldn't be able to curve as much as modern birds, probably, but we don't know for sure because this will vary due to extent cartilage etc. Either way, any amount of long neck feathers will hide the true extent of the neck pretty well. The neck feathers here are made longer than in caudipterids mainly due to the much smaller size. I did make the skull larger than the skeletal which seemed more naturalistic for a very small taxon than a scaled-down caudipterid.

  6. What this picture got me to think is that if we traveled to the Mesozoic, I doubt we'd be able to identify most coelurosaurs in the wild.

    If you saw a Saurornitholestes, would you be able to tell it isn't a Troodon? The latter is ~40% bigger, but the individual could be young, and people often have a hard time judging animal size. The snout on both would look shorter if the heads were feathered and could be hidden by feathers if similar to NGMC 91. You might be able to tell Troodon has smaller teeth, but it's not like you're going to get a view of that often, and the difference isn't huge. The neck and lower legs are longer in Troodon, arms and tail longer in Saurornitholestes, but could you tell under feathers and compared to a feathered body? The foot is more slender in Troodon, but would the 60% difference in width be obvious in life? The sickle claw of Saurornitholestes is larger, but both would look larger due to the keratin covering. Proportional differences are also hard to judge when you don't have the other taxon there for comparison. The best way I can think to distinguish them would be to see if the snout tip is pointed or rounded in dorsal view, but that's pretty sad for such disparate taxa. When it comes to taxa within the same family, I think we'd be completely screwed.

  7. I totally agree with Mickey. The features we regard as 'familiar' are (virtually) all skeletal, and they just wouldn't be obvious at all (bar the general form of cranial crests and osteoderms and whatnot) in live animals. I think we'd often be able to get a taxon to 'family', but other than that we'd have to start from scratch. It what makes that scene in Jurassic Park so annoying - as if little Timmy can look at an ornithomimid from a distance and know that it's Gallimimus (yeah, I know Gallimimus is big, but the ones in the film weren't _that_ big compared to other ornithomimid taxa). Of course, this is all part of the 'say no to shrink-wrapped dinosaurs' movement.

  8. @Darren & Mickey,
    Definitely agree, it would be tough, though in some cases the shape of the skull (or snout, at least) may help. Especially if you're dealing with a well-sampled ecosystem, like the lower Yixian for example, you might be reasonably certain that you're looking at say, a Beipiaosaurus, unless there are undiscovered but closely related species hanging around. But Graciliraptor vs. Sinornithosaurus, or even Caudipteryx vs. Protarchaeopteryx (let alone differentiating to the species level), would definitely be difficult without boiling a specimen or two down to bone :)

    That's why when doing reconstructions I try to develop some kind of 'theme' throughout each group (based on specimens with integument and color patterns if possible) and basically tackle it as though I were doing a family for the Spec. Dinosaur Project. It's tough to reconcile but doing realistic paleoart, IMO, means obscuring most of your research. If your audience can tell what species you painted without label or context, you're doing it wrong I'm afraid. (Minus those with prominent crests or other doodads of course).

  9. Hi Matt
    Would you mind if i used your picture of the maniraptor i was thinking of using it on a shirt.

  10. @Dave Go for it! Would be cool to see the finished product :)