Qinornis

66 million years ago, the end-Cretaceous mass extinction wiped out all dinosaurs except for the avian bird lineage.

…Or did it?

But I’m not talking about the dubious claims of non-avian dinosaur fossils found in places they shouldn’t be. This is about something else entirely: an unassuming little bird known as Qinornis paleocenica.

Living in Northwest China during the mid-Paleocene, about 61 million years ago, Qinornis was roughly pigeon-sized at around 30cm long (12″). It’s known only from a few bones from its legs and feet, but those bones are unusual enough to hint that it might have been something very special.

Uniquely for a Cenozoic bird, some of its foot bones weren’t fully fused together. This sort of incomplete fusion is seen in both juvenile modern birds and in adults of non-avian ornithurine birds from the Cretaceous – and the Qinornis specimen seems to have come from an adult animal.

If it was fully grown with unfused feet, then that would suggest it was actually part of a “relic” lineage living 5 million years after the mass extinction, surviving for quite some time longer than previously thought.

The last known non-avian dinosaur.

Shri

About 72 million years ago, in the Late Cretaceous of what is now Mongolia, a dead dromaeosaurid dinosaur lost its head.

30 years ago, in 1991, its headless fossilized remains were discovered during a joint Mongolian Academy of Sciences / American Museum of Natural History expedition in the Gobi Desert.

For a long time the specimen was known only by the nickname of “Ichabodcraniosaurus”, in reference to a character haunted by a headless ghost in the story The Legend of Sleepy Hollow – but now it’s finally been given a full scientific description and a proper name.

Say hello to the first new non-avian dinosaur of 2021, Shri devi!

Named after a buddhist deity, this little dinosaur was around 2m long (6’6″), roughly the size of a modern peacock or wild turkey. It was a very close relative of Velociraptor, but lived in a slightly different part of the ancient Gobi than its famous cousin, giving us a glimpse of how dromaeosaurid species varied across that region.

A map of the Gobi region of Mongolia and China, showing locations where various dromaeosaurid dinosaur fossils have been found.
[ From fig 28 in Turner, A. H. et al (2021). A New Dromaeosaurid from the Late Cretaceous Khulsan Locality of Mongolia. American Museum Novitates. https://doi.org/10.1206/3965.1 ]

Anzu

Named after the mythological bird-like Anzû – and also nicknamed “the chicken from hell” – Anzu wyliei was one of the larger known oviraptorosaurs, measuring about 3m long (9’10”).

Its fossils are some of the most complete for a North American member of this dinosaur group, with four different specimens representing about 80% of the whole skeleton.

Living right at the end of the Cretaceous, about 66 million years ago in North Dakota and South Dakota, USA, Anzu inhabited the ancient floodplains of Hell Creek and appears to have been a fairly fast-moving omnivorous generalist. It had a large crest on its head made of rather fragile thin-walled bone, which may have been used for display or sound amplification similar to the casque of modern cassowaries.

Some of the fossil specimens also show evidence of healed injuries, including a broken rib and an arthritic toe.

Glowing Dinosaurs

Many modern birds are capable of seeing into the ultraviolet regions of the electromagnetic spectrum, and some of their non-avian dinosaur ancestors might have had the same sort of vision. And much like their living relatives, that means various parts of their bodies and plumage may also have been UV-reflective and UV-fluorescent.

So here’s a Velociraptor with some speculative UV coloration – although this is just what it would look like to human eyes under a blacklight. What it would actually look like to a creature that can see extra colors is impossible to depict on a screen designed for trichromatic vision!

Island Weirdness #08 – Balaur bondoc

When Balaur was described in 2010 it was initially thought to be a dromaesaurid closely related to Asian forms like Velociraptor. With its particularly stocky legs built for strength rather than speed, two-fingered hands, and two large sickle claws on each foot, it was interpreted as a weird highly specialized predator terrorizing the other Hațeg Island species at the end of the Cretaceous. Although only 1.8m long (5’10”), it was hypothesized to have taken down prey much larger than itself with powerful slashing kicks.

But later analyses cast doubt on this interpretation.

A lot of the anatomical features of Balaur’s skeleton were odd for a dromaeosaurid, but matched those of avialans – a group of close evolutionary “cousins” to the dromaeosaurids, containing Archaeopteryx and the common ancestors of all modern birds. And, by 2015, multiple studies had confirmed Balaur wasn’t really a “raptor” but instead a little further along on the bird lineage.

So now our picture of this dinosaur is very different: a chunky-bodied island bird, grown large and secondarily flightless sort of like a Cretaceous equivalent to the dodo. Its double sickle claws were probably adaptations for climbing and perching in trees, and based on similar avialans it was likely a herbivore rather than a hypercarnivore.

Erlikosaurus

Erlikosaurus andrewsi, a therizinosaur from the Late Cretaceous of Mongolia (~90 mya).

Named after Erlik, the Turko-Mongolian god of death, it’s only known from partial remains – but it was the first therizinosaur ever found with a preserved skull, helping to fill in some of our knowledge of these oddball dinosaurs’ anatomy.

It was closely related to Therizinosaurus, but was only about half the size, estimated to have measured around 4-5m long (13′-16’4″). It would have had a toothless beak at the front of its jaws, an adaption for a herbivorous diet, along with long claws on its hands and a coat of fluffy down-like feathers. I’ve also given it some longer quill-like feathers here, similar to those known in Beipiaosaurus.