Day #3 on our Christmas Countdown is…

Concavenator!

Concavenator: the “Cuenca Hunter”

Concavenator was a medium-sized predator from Early Cretaceous Spain, and has been the source of heated debate on forums ever since it was described in 2010.

Why the debate?

The fossil skeleton was articulated and almost complete, and it had a few rather unusual features. One of those features are the special back vertebrae that look like they support some sort of sail or hump. A fattier or muscular hump is most likely because of the flattened shape of the spines, but what it was used for exactly is unknown.

The really odd thing about this dinosaur were the bumps along the arm bones, and the debate is whether these bumps were quill knobs or muscle attachment scars. Maybe there wouldn’t be so much debate if we didn’t have scales preserved. Broad, rectangular scales along the underside of the tail, and feet very much like a bird.

But what are quill knobs? Those are small knobs on the bone formed from all the tissues that anchor the large flight feathers on a bird’s wing. Usually, these are only seen in birds and dinosaurs with winged arms like Velociraptor. On the list of birds, there is an unusual one that I think we can look to for a clue.

The cassowary.

Now cassowaries do not have wings in the way that we might think of wings. Instead, their arms are covered in thin feathers that look like shaggy fur, and instead of large feathers like you would see in an ostrich, there are four long, hollow quills. And they have quill knobs on the bone.

So how much of Concavenator’s body was scales, and how much was feathered?

Well, Concavenator comes from a group that is typically known to be all scaly, so it’s very unlikely to be covered in feathers. Not impossible, but until we have more fossils I think it would be a very speculative interpretation to draw it covered in furry feathers. Now I love speculative drawings of dinosaurs and other prehistoric critters, and so I always enjoy seeing the many different ways people draw Concavenator. It gives fuel for the imagination, and many dinosaurs would probably look very different from how we imagine them anyway.

I chose a more conservative approach for mine, just because of personal preference for this critter. The humpback makes me think of a double-duty feature that could help with communication and display, a lot like some hump-backed lizards, and so I looked at the decorative scales and colors a lot of these lizards have.

It would be quite odd to only have quills on its arms and nowhere else though, so I gave this guy some sparse feathering a bit like the fuzz on an elephant. I’ve had chickens with feathers growing between the scales of their feet, so who knows? It’s just one possibility.

How do you imagine this landshark? Scales, feathers, or a combo of both?

See you tomorrow for day 4 of the Critter Christmas Countdown!