maniraptorans

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Who was the earliest bird: Archaeopteryx, as has long been thought, or Aurornis, a newly-described Chinese paravian? Nature News explores this issue in a new article that features this illustration of these two dinobirds facing off in a conceptual battle for status.

Contra the Nature article, and while the true phylogenetic position of Archaeopteryx is certainly a fascinating issue and deserves resolution, the reality is that it does not matter whether good ol’ Archie was a bird or something very, very similar to a bird. Modern phylogenetics has rendered the distinction logically irrelevant: whether Archaeopteryx is the first “bird” is now an issue of semantics more than one of science. So let’s try to cut back on the uproar over who was truly the earliest bird—there are enough worms to go around.

Gouache on artboard, 16" x 20", processed in CS4.
Available as a print.

Also pictured: Kulindadromeus, a basal neornithischian covered in voluminous feather-like structures, and Zanabazar, a late Cretaceous Mongolian troodontid.

What was 11 meters (36ft) long, had a sail on its back, and had arms bigger than an adult human?

Deinocheirus mirificus!

Yep, the big paleo news this weekend was the official announcement of some new fossil material for this particular dinosaur.

Deinocheirus (“terrible hand”) came from the Late Cretaceous of the Gobi desert, about 70 million years ago. Originally discovered in 1965, the only bones known were a set of enormous arms and a few scattered ribs and vertebrae. It was a long-standing mystery for paleontologists. Was it a megalosaur? A carnosaur? Some new type of theropod altogether? A predator or a herbivore?

Some more recent studies suggested it might be an ornithomimosaur, albeit a fairly primitive one based on the arm anatomy. With the two new specimens that have been found, we’ve now got confirmation of that placement – Deinocheirus really was an enormous “ostrich mimic”, the largest known for that group.

And it had a sail-back.

I don’t think anybody was expecting that.

This is the famous Velociraptor mongoliensis in its native late Cretaceous Gobi Desert. Velociraptor was a small dromaeosaur, or raptor dinosaur, and contrary to its most famous depictions was almost certainly feathered from head to tail. This is no longer based merely on phylogenic evidence, either - as of 2007, reanalysis of the fossil has shown that its posterior forearm contains quite obvious quill knobs.

Velociraptor surely went after larger prey like Protoceratops at least occasionally, as we have fossil evidence that it certainly did so. However, like many modern mid-sized carnivores, its diet probably consisted of a large proportion of much smaller animals, which it may have ambushed or sniffed out of crevices. I imagine such a predation event would have been rather felid in nature, wherein the animal displayed a curious mixture of predatory grace and pure silly ridiculousness as it bounced and flailed after a frantic prey animal. In this case the prey in question is Zalambdalestes, a small shrewlike eutherian from the Djadochta Formation of Inner Mongolia.

K is for Khaan

Khaan mckennai was an oviraptorid from the Late Cretaceous of Mongolia, about 75 million years ago. About 1.2m (4ft) long, it was initially identified as belonging to the genus “Ingenia” before being assigned its own unique name in 2001.

Oviraptorids were members of the maniraptorans, closely related to birds and “raptors”. They were initially considered to be specialized egg-eaters due to an Oviraptor fossil discovered on top of a nest which was thought to belong to the ceratopsian Protoceratops. (Hence the name “Oviraptor”, meaning “egg thief”.) Later specimens found during the 1990s showed oviraptorids clearly brooding on top of nests, however, and the original eggs turned out to have belonged to the Oviraptor the whole time.

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Doodling dinosaurs before bed. Above, a startled troodontid raises her hackles, exposing the white feather bases, a warning that you’d better back off. Below, a young Graciliraptor has captured a large beetle, which will make for a delicious meal.

Here is my rendition of Eosinopteryx brevipenna, the new troodontid described last week in Nature Communications. This tiny feathery, from the Late Jurassic Tiaojishan formation of Liaoning, China, differs from other basal troodontids in that it lacked the long feathers on the metatarsals and pes that typifies related animals, such as Anchiornis. It also had much shorter footclaws than related species, and this together with the lack of “legwings” indicates it was very likely a terrestrial bird. The animal is also a bit unusual in that its tail is rather short and lacks any sign of retrices, which gives it a bit unusual and somehow more “primitive” appearance than its relatives.

Here, the little fellow perches atop a mossy stump, possibly the highest vantage point it was able to manage. The paper makes no mention of whether the ungual on the second digit of the foot could be retracted, but the fossil’s second pedal claw is clearly larger than the other claws on the foot, so it’s possible it was used to aid in balance as well as predation.

Photoshop CS4.

Here’s my submission to Love in the Time of Chasmosaurs’ version of the “All Yesterdays” contest. This version of the contest is differentiated from the original by requiring the artist to illustrate the speculative behavior in a style different from their usual, with a specific emphasis on straying from the hyper-detailed, realistic style that most paleoartists seem to be trying to capture these days. I tried a sort of cell-shaded, pseudo-vector type of look for mine, which I’m sure most of you will notice is very different from my usual fare.

Anyway, this is a little different from most entries to this contest in that while it’s speculative, it is something that I genuinely believe is the case (that Microraptor was an omnivore), and I think it’s perfectly possible that one of the ~300 undescribed specimens of this animal may preserve plant matter gut contents. Hard to say. In any case, I think that Microraptor has certain features that are consistent with omnivory in maniraptorans, including having somewhat unusual dentition by dromaeosaur standards.

Here I’ve depicted it munching on a tasty cycad fruit.

I intend to do a more in-depth blog post exploring this concept sometime in the coming weeks. I also hope that my watchers aren’t sick of me drawing Microraptors yet… there will be more to come.