A true paleo diet: dinosaurs eating fish

There’s been a lot of talk about “paleo diets”, but here we have the real deal. A meal caught in the middle of digestion in a dinosaur.

Microraptor gui was introduced back in 2003, and immediately attracted attention because of the its feathers, particularly lots of long, prominent feathers on its hind legs, so unlike any bird or other flying beast we know of. There is good evidence (though disputed) that it was a glossy, black animal, rather like the grackles that hang around my campus.

But behaviour is one of the trickiest things to pull from fossils. How did these animals live?

Here is the newest fossil to shed light on this question in Microraptor.

Just in front of where the hind legs meet the spine, and below the spine, there is a mass that is a little darker than the surrounding rock. There are close ups of this area in the journal article, but the reproduction is disappointingly low-resolution in the pre-print, and in any case, relatively few would immediately recognize the key feature there.

Fish bones. There is nothing but fish bones in the gut of this dinosaur. Authors Xing and colleagues say, “M. gui was an adept hunter of aquatic prey.”

Still, are there any other indications in the anatomy that Microraptor gui was a habitual fish-eater? After all, all kinds of meat eaters will pick up any meal that’s available. It is at least possible that this one individual M. gui scavenged some leftovers off someone else’s plate, so to speak.

Xing and company say that evidence against this being scavenging is that fish spoils quickly, so the window of opportunity would be small. However, other M. gui fossils have bird and mammals bones, suggesting this species may not be a picky eater.

Microraptor may not be alone in its fish-eating habits. It’s been suggested that much larger dinosaurs were fish-eaters:

When Jurassic Park 3 came out, I snickered a little bit at the use of the Spinosaurus as the “big bad” monster to up the ante over Tyrannosaurus rex. Because a quick visit to wikipedia indicated that people thought this spiny beast ate fish, based on the skull, and backward facing teeth (think of fishhooks to keep the prey in place). In Jurassic Park 3, it was definitely not eating fish. That might have taken a bit of the “scare factor.”

Are there any anatomical features that support M. gui as an “adept aquatic predator”? This fossil gives previously unseen views of the teeth in this species. The only thing that might be related to a possible fish diet is that some of the teeth are not serrated, and some of the very frontmost teeth point forward. Both features are apparently common in fish-eaters.

Given that well-preserved Microraptor fossils seem to emerge regularly, we can probably expect still more insight into how this interesting little beast lived. Not bad for something we didn

It s wonderful to think that ten years ago, we didn’t know Microraptor gui ever existed (the genus was named in 2000, M. gui named in 2003). Now, we know what it looked like and what it ate, putting is well on the way to becoming one of the best “fleshed out” dinosaurs.

Reference

Xing L, Persons WS, Bell PR, Xu X, Zhang J, Miyashita T, Wang F, Currie PJ. 2013. Piscivory in the feathered dinosaur Microraptor. Evolution: in press. DOI: 10.1111/evo.12119

External links

There’s something fishy about Microraptor (Of course Switek beat me to this!)

Microraptor reconstruction from here.