Creodonts & The Absurdity of Extinction

I just fell down a rather wonderful rabbit hole. My tale begins with a book review, written by Ross Barnett, of Sabretooth (Mauricio Anton). Apart from instantly causing me to add the book to my “to buy” list, the article also briefly lists the various mammalian clades which have exhibited sabre teeth in the past. Amongst this list were those I had expected, such as machairodonts (e.g. the famous Smilodon) and the marsupial Thylacosmilus, but it also contained several I had never heard of. Most notably, it mentioned creodonts.

If I’ve ever come across creodonts before I wasn’t paying much attention because these creatures are fascinating. As a group they are an early success story in the mammalian radiation that occurred at the ending of the Cretaceous, yet despite their broad range and varied niche placement they are now utterly gone. Whilst they may look akin to modern hyenas, cats and even bears, the creodonts are not closely related (or basal) to the carnivorans. They are their own unique, and now absent, thing.

I’ve always found the notion of entire clade extinction somewhat absurd. I remember first reading about the K/T event that signalled the extinction of the dinosaurs and, even at an age written in single figures, feeling that there was something inherently wrong with the narrative. I get how large, extinction level events cause biodiversity to crash, but the idea that such a wildly successful and diverse group of creatures would all succumb seemed silly. I must admit, then, that as I’ve aged it has been with increasing smugness that I’ve watched the consensus switch from “dinosaurs are extinct” to “non-bird dinosaurs are extinct”. Frankly, at this point, I feel the old narrative should just be ignored. The K/T event knocked several wonderful animal groups on their respective heads, but the dinosaurs were not amongst them.

Still, though, the plesiosaurs, pliosaurs, ammonites and myriad pterosaur groups were all wiped out, amongst many, many others. Whole families, even genera, do go extinct, often with frightening rapidity when everything is considered. That still feels odd, plus more than a little disappointing, and I can now add creodonts to the list of groups which I would love to have had the chance to meet.

But my journey didn’t stop there. Intrigued and fired up by the beautiful imagery of Sabretooth, I went hunting for palaeoart of creodonts. Unfortunately, I largely came back empty handed, but my wide Googling did lead me to discover a new blog to subscribe to: Into the Wonder. It’s a loose connection to the subject I was after, but it’s always fun to discover someone actively writing about developing fantasy lore and creature creation!

Plus, who knows? It took over a century for someone to realise the creodonts were not just another branch of Carnivora, which is a large enough group for some individuals to have only undergone cursory examination, so perhaps they actually aren’t all gone. Maybe, just possibly, one day in the future, some slightly odd mustelid or squash-faced felid will turn out to be a creodont in hiding. Maybe that discovery will even answer questions about an unsolved riddle of folklore? It’s possible… though it’s probably also asking far too much…

Awesome Azhdarchids [#9]

Two giant pterosaurs striding over an ancient grassland hunting small dinosaurs.
Image from Naish & Witton 2017

Looking through my article categories it would seem that I’ve never blogged about prehistoric creatures at all on this site, which is frankly ridiculous. As such, a post such as this one is well past due. Plus the subject matter, in my opinion, is ridiculously cool (that likely says more about me than the source material, though).

I’ve followed Darren Naish’s ideas on Azhdarchid behaviour very closely over the past few years, partly because I’m generally a fan of Naish’s work and partly because the concept is just very exciting to me. The popular image of pterosaurs rarely expands beyond the concept of reptilian, bat winged flying creatures that were ultimately a poor man’s bird, replaced by the evolutionary advancements made by their avian (distant) cousins. Of course, that’s a load of nonsense: pterosaurs, of all sorts, were fascinating creatures that occupied a huge variety of niches and continued to be highly successful for millennia after birds first evolved. Not only were they incredibly varied, but they often branched out into niches that today’s birds can barely scrape, achieving evolutionary feats that have never been paralleled.

Arguably, one of the clearest examples of pterosaur splendour is the most well known Azhdarchid: Quetzalcoatlus. Famous for its gigantic wingspan, most likely topping out somewhere around 11m, Quetzalcoatlus and its kin are far more interesting than merely boasting the largest wings to have ever evolved. The Azhdarchids are also a bit of an enigma.

Their huge wing spans and, in general, huge sizes have never fit well with the more archaic notion of pterosaurs as bird analogues. When we look at living (or even extinct) birds, the closest niche that seems to fit is that currently embodied by the albatrosses: huge winged ocean wanderers, gliding for days over the waves and feeding on the wing. Azhdarchids are certainly well designed for long-haul gliding, likely (again) being the best long distance gliders to have ever evolved, but they don’t fit as albatross analogues because they largely didn’t live near the sea.

The vast majority of Azhdarchid remains are found in continental interiors, far from evidence of large bodies of water, so the traditional interpretation of them as oceanic just doesn’t make a lot of sense. Naish and Mark Witton are two of the more prominent figures putting forward an alternative theory: Azhdarchids as giant, terrestrial land striders. Storks or secretary birds would become their closest living analogues, but these pterosaurs simply outflank all modern birds in terms of size. To quote Naish directly from his latest blog post on the matter:

Small dinosaurs – up to the size of humans – were very plausibly on the menu for this animal.

Here Naish is referring to a more recent discovery, the robust Romanian Azhdarchid Hatzegopteryx, but increasingly it seems similar to other ideas being put forward at the edges of the scientific community. Indeed, in their latest paper on the matter, Naish and Witton advance an even more radical concept: Hatzegopteryx as the top predator in its ecosystem. It’s an idea I absolutely love and one I will continue to follow closely, both in the technical literature (where possible) and in popular science reporting (which has a tendency to lag somewhat). I may even, in the future, use the Azhdarchids as part of another project I’m working on. At any rate, the concept of these gigantic pterosaurs being not only terrestrial predators but potentially sitting at-or-near the top of their respective food chains is just another example of how, often, pterosaurs just outclass modern birds.