Caturday Special The Origin Story: Proailurus and Pseudaelurus

A preserved skull of Proailurus lemanensis, from the Museo di Storia Naturale di Calci – Pisa. See below for a comment suggesting this skull may have some errors in its restoration and may not reflect the actual make-up of a Proailurus lemanensis skull. (Credit: Ghedoghedo)

Roughly translating to ‘before cat’ (even though it’s first cat) and ‘fake cat’ (even though its real cat) respectively, Proailurus and Pseudaelurus are the ancestral genera of all cats.  Do you remember the lesson from last time? Genera is the plural of genus and is the classification of living things, the group above, in sequence, a species.

As with most prehistoric creatures, especially small ones with fragile bones that turn into brittle, little fossils, not much is known of these creatures and not much can be found out without more examples in the fossil record.

Proailurus is considered the first ‘felid’ genus, it is debated whether pseudaelurus evolved from proailurus or evolved independently. Current thinking is that pseudaelurus likely evolved from one of the Proailurus species.

An artists impression of Proailurus lemanensis Note the flatter head and stouter limbs, similar to the jaguarundi (Credit: Roman Yevseyev)

Analysis does seem to indicate that Pseudaelurus is the ancestor of all current feline groups, as well as some famous prehistoric ones (sabre-toothed cats, we’re looking at you.)

How is this analysis done? After all it’s very hard to extract DNA from a rock? And that’s basically all a fossil is.

Well for the most part, and one of the reasons relations of prehistoric species are constantly shifting, it’s done through bones. Certain developments, changes in bone-structure, over time, can be traced through the fossil record. With good sample sizes (e.g. dinosaurs into birds) we can see, for instance, how the dinosaur pelvis structure translates into birds, how their wing bones developed, how their skulls morphed into beaks etc.

By the time we get to Pseudaelurus sp. we start to see significant diversification of size and shape. Some cats are smaller, squatter, some taller and bigger, and when most of what you have to go on is a jaw fragment paleontologists have to work very hard to look for clues. (Credit: © 2016 – 2021 lythronax-argestes – Used without permission as I couldn’t find any way to get in touch with you. I love what you do!)

When we’re talking carnivores, skulls are very important, eye placement, jaw structure, number of teeth, tooth placement and the various ridges and crests that would indicate a mounting point for muscles are all important ways to spot development along a lineage, or maybe separate two groups.

Proailurus species were likely very compact, closer in form to the modern Viverridae, species like the civet and the genet (considered in the sub-order Feliformia, therefore cat-like, but not true felids). This along with the sharp teeth found in the jaws of fossils suggests they would have been sneaky, slinky tree hunters and what better place for cats to start?

By the time we get to pseudaelurus species they are getting much larger, with some estimated to have been around the size of a cougar, and, given their relation to sabre-toothed cats, an increase in the size of their canine teeth.

A small Indian civet (Viverricula indica) with its distinctly feliform features. Though longer in snout than most cats, things like the basic body structure, the markings etc. it has in common with many feliforma. There’s also a type of civet they feed coffee beans, make them shit them and sell them at a ridiculous price. (Credit: Rejaul karim.rk)

Proailurus has mainly been found in Europe, with isolated specimens in Asia and North America, pseudaelurus shows a much wider distribution, the largest number of fossils having been discovered in North America, but examples also coming from across Europe, Asia, in the middle-east and even from Africa.

So we can see where cat distribution came from, and we also get an idea of their evolution into different lineages, filling different ‘niches’ – a biological niche, not unlike a niche in marketing or any other use of the term, simply means its little corner. What habitat it lives in, what food it eats, where it dens or nests – that sort of thing.

I wanted, so desperately to cover a proailurus species in the top ten but there’s just not enough known and far too few cute images. I couldn’t even have paid the kitten tax!

So I figured I’d make a separate entry to let you know where cats came from. I mean, pre-proailurus is…it gets weird. Mammal evolution has been crazy. Giant, carnivorous horses and sloths the size of buses, swimming cow-pigs turning into whales, going all the way back to cynodonts, small mammal-like reptiles of the Permian and Triassic.

A model of the head of an Andrewsarchus mongoliensis – an extinct mammal from around 50-30 million years ago. In the order of Artiodactylae (the even-toed ungulates – same group as giraffes and pigs) it is likely most closely related to a hippo. It is mainly known from it’s 83cm long lower jaw found in Mongolia. So…imagine a carnivorous pig-hippo with a near metre long jaw. This is why as far as I am concerned you can stick most dinosaurs up your arse. (Credit: Ben Sutherland)

It was a long road, how much longer still only time can tell. But it’s good to know where you (and cats) come from to see how far you’ve come since it all started.

Why not check out our Top Ten Cat Species List, starting with our Introduction if you haven’t already?