“Difficult to buy hats for”

Despite considering myself a zoologist who happens to work on dead things, rather by default of my jobs I know quite a few geologists. Recently I was chatting to my old buddy Mat Watson from the University of Bristol while the poor guy was stranded in an anonymous US airport trying to get home from some fieldwork in Hawaii (ah, the hard life of a volcanologist). The subject turned to a dinosaur news article Mat had seen concerning ceratopsians and I mentioned that really, that had nothing on the nyctosaurs and on showing him a picture, his reply became the title of this post.

Yes, this time we are on the nyctosaurs, those fantastic aeronauts with the best (and certainly the most improbable) headgear of probably any animal in history. They really don’t get much attention as other pterosaurs which is a shame for several reasons which will become clear shortly, and typically just goes to show the inherent human bias against things which don’t *look* interesting, even if they *are* interesting.

Nyctosaurs are, according to most researchers, close relatives of Pteranodon and certainly Nyctosaurus and Pteranodon overlapped in time and space being found in the Late Cretaceous Niobrara chalk for Kansas and nearby states. They might be more distant relatives, but however you spin it, the nyctosaurs are derived pterodactyloids of some kind and linked to the ornithocheiroids.

They lived in the Late Cretaceous and are so far only known from the Americas, with Nyctosaurus coming from Kansas and surrounding areas and Muzquizopteryx (previously seen here thanks to the ossified tendons of the arms seen in the group) being Mexican. Yep there are currently only two genera known for this group which is, well, not many really.

Like the (other?) pteranodontids and the azhdarchoids, the nyctosaurs are toothless and had long jaws capped by a beak. Given their location, they were presumably ocean-going fliers and piscivores, though we don’t really know for sure it’s a reasonable inference. They are, for Late Cretaceous pterosaurs, also rather small – only around 2 m in wingspan so less than half that of Pteranodon for example.

Nyctosaurus is, these days, famous for the quite extravagant forked crest that adorns it’s skull, though this was only discovered pretty recently thanks to two rather controversial specimens (though, I should add, not the research). Previously, Nyctosaurus was thought to only have rather a nub of a head crest like that seen in Pteranodon ‘ingens’ (now widely considered a female morph and not a separate species) and indeed in the sole specimen of Muzquizopteryx.

Nyctosaurus specimen KJ1 from Bennett, 2003 fig 2.

Nyctosaurs have another, rather more unusual morphological characteristic to go with the occasional giant crest. They have no hands. Or more specifically, they lack both digits 1-3 and the corresponding metacarpals. The wing finger is there, or course, and the enlarged fourth metacarpal that it sits on, but the others have gone. This took a long time to confirm as while suspected this is of course and absence issue and it’s hard to prove that something is genuinely missing from an animal’s anatomy and not just not present in the specimen. In this case it was the recovery of multiple arms (including complete ones) with never a trace of any fingers apart from the wing. It’s highly unlikely that these bones were repeatedly the only ones to go missing during decay or disturbance, especially when a complete and articulated wing or whole skeleton is otherwise present. This actually fits with the inference of a highly specialised ocean specialist that landed only occasionally and so simply didn’t need those fingers for walking or clambering around.

That’s the real basics of the nyctosaurs laid out, we actually really don’t know much about them as there are few good specimens and only two genera going and much of what has been sorted out or is especially interesting has only been learned recently. There is surely more to come and given the plethora of azhdarchoids that have turned up recently it’s a bit of a surprise and rather disappointing that only Muzquizopteryx has appeared to add to Nyctosaurus, but my guess is that it is only a matter of time before more taxa arrive on the scene and I have heard rumors at least of others.

Finally thanks to John Conway for letting me use his awesome video of a Nyctosaurus flock in flight.

@Dave_Hone on Twitter

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