Blue Collar Scientist

So I’m enjoying a low-pressure Saturday afternoon, clicking the “StumbleUpon” button, and it takes me to the Dinosaur Facts site - specifically, the page about Eudimorphodon. On that page I notice the following text:

The Eudimorphodon was a flying dinosaur that lived in the late Triassic period.

Now, I’m not an expert on dinosaurs. What I know about dinosaurs and carry about in my head would not be too much trouble to write down. But it seemed to me that Eudimorphodon was not a dinosaur, but in fact was a pterosaur. The picture certainly looked like that of a pterosaur. And I hadn’t really heard of non-feathered flying dinosaurs anyway. And one last objection - a flying dinosaur in the late Triassic? Not impossible, I suppose, but I don’t recall hearing of such a thing.

A quick look at Wikipedia seemed to confirm that Eudimorphodon is a pterosaur.

Now if there’s one thing that motivates me, it is finding errors. Having found this one, I decided to read the rest of the page. I read to the end and then I look at (what in print media would be called) the sidebar, which is titled Did you know, and which contains this gem:

Eudimorphodon was a pterosaur, not a dinosaur.

Er, ok then. Contradictory information on the same page just bugs me, but that’s the web for you. At least this time they had the right answer.

But here’s the thing. I don’t actually know what a Pterosaur is. Yes, I know that it is a flying Mesozoic reptile - I just don’t find that to be very meaningful. So I did a little web searching, and I quickly realized that for me, “what is a pterosaur” is answered not by the mantra about flying reptiles, not by their morphology, but by their phylogeny. Their phylogeny is not yet super-well established, which makes drawing firm conclusions chancy, but nevertheless cladograms exist. Looking for one led me to this image (from here):

So Pterosaurs are closer to the dinosaurs than crocodilians, but diverged before the dinosaurs originated. Nice. That’s actually a perfect answer - it tells me exactly why pterosaurs aren’t dinosaurs, and also suggests some attributes of Pterosaurs that it wouldn’t share with dinosaurs, or crocodiles.

So, why are we still using the mantra “flying reptile” to describe a Pterosaur? Phylogeny and phenotype together do a much better job, yes? Why do none of the benchmarks or standards used by the teachers I work with include cladograms? I’m sure this concept can and should be explained to 9-12 students.

The BBC, LiveScience, and others are reporting on the discovery of a new pterosaur found in north-east China. The find also confirms a prediction of evolution. From the BBC story:

“It is very likely that this pterosaur represents a lineage of arboreal creatures that lived and foraged for insects in the gymnosperm forest canopy of north-east China during the Early Cretaceous,” the researchers write in PNAS.

They conclude this from curved bones in the feet, which are similar to those found in perching birds. This pterosaur is also smaller than most others, of a size that makes sense for perching on branches. Cladistics suggest that this pterosaur was close to the ancestors of the giant pterosaurs, including Quetzalcoatlus, which had a 30-foot wingspan. Thus the new fossil is transitional, being in some ways less derived than later specimens but more derived than the pterosaur’s hypothesized concestor.

“It is interesting to see some clear arboreal adaptations in this species,” said [Smithsonian paleontologist Matthew] Carrano, who was not on the research team.

“It confirms a suspicion we had, that pterosaurs were more diverse in their habitats than we knew from the [fossil] record.”

Let’s be a bit more direct here, in the interests of effective science outreach and clear communication. The notion that pterosaurs were more diverse (in their habitats, or in their phenotype - both apply) than the fossil record previously demonstrated is a prediction of evolutionary theory, not merely a suspicion of paleontologists. There are actually two predictions here, both of which are confirmed by this fossil.

1. Evolution predicts that some species will be absent from the (known) fossil record, and that some of them, if they were known, would illuminate the evolutionary development of their lineage. Here we have an example of a fossil which was unknown until recently, and which does just this. Score one for evolution.
2. Evolution makes the more specific prediction that, when you have lots of fossils of lots of species with specialized adaptations - such as pterosaur fossils - that less derived species will exist earlier in the lineage. Not only that, but it says that most of the characteristics that are common to most or all of the more specialized species will be present in the less derived one. Again, from what’s been published, this fossil confirms this prediction.

Seems I’m on a paleontology kick lately. Undoubtedly this is a result of spending so much time in museums over the last month, looking at fossils. Fair warning - there’s at least one more of these in the pipeline. I’ve had some interesting information and photos from the PI of the crayfish fossils I reported on earlier that I’m working up.