Colours of Wildlife: Burnetiamorphs
Created | Updated Jul 22, 2018
Burnetiamorphs
Willem is a wildlife artist based in South Africa. He says "My aim is simply to express the beauty and wonder that is in Nature, and to heighten people's appreciation of plants, animals and the wilderness. Not everything I paint is African! Though I've never been there, I'm also fascinated by Asia and I've done paintings of Asian rhinos and birds as well. I may in future do some of European, Australian and American species too. I'm fascinated by wild things from all over the world! I mainly paint in watercolours. . . but actually many media including 'digital' paintings with the computer!"
 |  |
 |  |
 |  |
Just look at these old doggies! Wouldn't you like one as a pet? I would! Sad to say, we've missed them by about 260 million years. These are Burnetiamorphs, a group of weird, dog-like pre-mammals, fossils of which have been found in South Africa and Russia.
These are of course part of the book on Earth's prehistoric life that I'm working on. In the book, things will be well-ordered in terms of time, place and relationships; in this column, you're getting them in the order I'm working on them rather than the order they're going to be in in the book. And I'm working on them based on what I feel most inspired to do at any given moment. These come very high on the list of ancient things that inspire me, which is why you're getting them quite early on in the endeavour.
So, to set the time and place more properly: the Late Permian period, about 265-255 million years ago, left its well-preserved fossil-bearing rocks mainly in South Africa and Russia, though there's every reason to believe that similar animals to the ones found there, would have lived in the rest of the world also. Planet Earth looked different then; the continents were joined into a huge landmass called Pangaea. It was thus no great matter for critters to walk from what is now South Africa to Russia or to what is now Europe, North and South America, or even Antarctica and Australia. Nevertheless, there were some regional differences, because of climatic zones and barriers like mountains and deserts.
The Permian period is the last of what is called the 'Palaeozoic' age, or the age of Ancient Life. Lots of things happened before and during the Permian. It was the time when land animals really got going and diversifying. It was preceded by the Carboniferous, which was the period when forests first started growing all over the world – the name comes from the coal (mainly carbon) laid down over millions of years by these first forests, which we're still exploiting today. But the Carboniferous forests were composed of weird plants, huge specimens related to the much smaller modern horsetails and club-mosses. The Carboniferous ended with the forests dwindling; the ensuing Permian period was a drier one, with expansive deserts. Forests were still around, though, and starting to include plants which we would not find so strange to see today, including the first conifers. In the drier climates, the reptiles and amphibians developed into tougher types that could better avoid or endure desiccation. The type of critters which emerged in the Permian as the dominant land-living forms, were the synapsids, the group to which modern mammals (including us!) belong. The synapsids, already present but not yet highly diversified in the Carboniferous, underwent an explosion of evolution, leading to a vast range of sometimes familiar, sometimes bizarre types. The Burnetiamorphs were somehow both.
Outwardly, Burnetiamorphs looked much like dogs. They were all about the size of a cat to the size of a mid-sized dog. They walked with their bodies held well off the ground, and had relatively short tails, rather than the long, lizard-like tails of the more primitive synapsids that went before them, like the pelycosaurs. In their skulls, their teeth started to diversify. They didn't have chewing or shearing cheek-teeth yet, but there was a distinct difference between the small, nipping incisor teeth in the front of their mouths, and the large, stabbing canine teeth, of which as in modern mammals, there was just a single pair in each jaw. The post-canine teeth were small, simple and sharp. The burnetiamorphs would likely have differed from (most) modern mammals in not being furry. Instead, they likely had smooth, leathery skins, probably with glands in them to secrete oils and sweat. It is a contentious issue at the moment, exactly when the ancestors of mammals first gained their furry coats. Indirect positive evidence suggests that fur was very likely present in the advanced cynodonts, which came along quite some time after the burnetiamorphs; but there are also traces of what looks like fur in some fossil dung dating from the late Permian. Burnetiamorphs were likely not the source of that, since more advanced synapsids like early cynodonts, therocephalians and gorgonopsians were also present at the time and much more likely to be furry. So for now I've drawn them without fur. But I'd be delighted to change my mind, if evidence of them having fur should surface.
The funniest thing about the burnetiamorphs, and that distinguishes them from other synapsids around at the time, is the bumps and lumps they had on their skulls. This went along with an expansion of the rear regions of the skull, which would have given more attachment space for the jaw muscles and consequently a stronger bite. To some degree, the overgrowth of the skull would also have strengthened it, so as to transmit these stronger forces effectively. But there also seems to be an ornamental element; the exact design of bone thickenings differs distinctly between the different species. It is possible that these ancient doggoids might have bumped their skulls and faces together in ritual combat. Maybe it was just for display, two combatants rather trying to intimidate each other with fierce looks rather than physical ferocity.
Let's look at a few representatives. Lemurosaurus pricei is one of the most 'primitive' of the burnetiamorphs, in showing a not very specialized condition. About the size of a cat, it had modest skull growths, the most prominent of which were a pair of devil-like 'horns' over its eyes. These eyes were quite large, reinforced with rings of bone (sclerotic rings, still found in some modern animals), and it might have been nocturnal. It's known (at present) from two fairly well-preserved but distorted skulls. It might very well have grown bigger; the known specimens might be from juveniles. It was found in the Karoo region of what today is South Africa. I've committed a 'no-no' in this reconstruction by showing its upper canine tooth exposed; there's a group amongst the paleo-artists who believe that very few old critters actually had exposed teeth. I'm not personally convinced by all their arguments. Many of these old synapsids had very long, even sabre-like teeth, and 'hiding' these when their mouths were closed, would have necessitated huge lips and 'sheaths' in their lower jaws, which I don't consider very likely at this level of development. I'd have much less of a problem with an inch or two of protruding tooth.
Lobalopex mordax reached an overall length of about a metre. It had a long muzzle with fierce canine teeth, and just a few bumps on its face and skull. I've coloured them brightly to make them more prominently visible, as might indeed have been the case in life, if they were important for display. They wouldn't really have served for anything else than display. Lobalopex was also found in South Africa.
Bullacephalus jacksoni is another South African burnetiamorph. The known skull is very well-preserved but misses the front part of the muzzle. There is a bump on the top of the muzzle, and thickened bone margins in the rear part of the skull. I've not tried to guess what its nose looked like, instead reconstructing it here with that part of its face hidden! It is feeding on a large dicynodont, a plant-eating type of synapsid which also were numerous in the late Permian. You'll of course see (hopefully soon) an entry dedicated to these beasts also.
Proburnetia viatkensis is, for a change, a Russian species. Its beautifully preserved skull shows thickened bones around the eyes and rear margin of the skull, and bumps over the nostrils, snout, eyebrows, cheeks and back of the skull. These might have been overlain with thickened skin, or even by keratinous horn-like growths which went much further out from the skull, in which case it would have had a very weird face indeed. I've reconstructed it conservatively here, just showing the bumps that are present on the skull itself. I'd be thrilled if more fossils of this and similar animals turned up in Russia.
Paraburnetia sneeuwbergensis is again South African. It had broad, flaring margins to the rear of its skull, and numerous thickenings around its face, especially over its eyes. I reconstructed it here with bright colours emphasising these, as two animals in conflict show off to each other. Again note the scandalous bit of protruding tooth in my reconstruction!
Finally, here's the one for which the group is named, Burnetia mirabilis. Also South African, this is known from just a single, rather distorted and imperfectly preserved skull. Not very big, this fossil nevertheless shows extraordinary expansions and thickenings over the snout, eyes and rear of the skull.
A few more burnetiamorphs have been found, including an interesting specimen from the African country of Malawi. Generally, though, the group seems to have been rare, known from far fewer fossils than many other contemporaneous groups. Their record ends abruptly in the Late Permian. The end of the Permian was marked by a massive global calamity that led to the extinction of 90%-95% of all sea-living species, and 70% of species inhabiting the land. A vast numer of experiments with different shapes and lifestyles thus ended in ruin. Numerous groups of synapsids other than the burnetiamorphs also didn't make it through either, but luckily (for us) a few of the cynodonts did, along with some of the dicynodonts and therocephalians. The cynodonts evolved into the true mammals, much later, around 200 million years ago in the Late Triassic. But then they had to contend with yet another new and suddenly very successful group – the dinosaurs. While these grew big and took over the main ecological niches by daytime on land, the mammals had to remain small, inconspicuous and mostly nocturnal so as to survive. Only after another hundred-and-thirty-five million years, when the (non-avian) dinosaurs went extinct, could the synapsids – now in the form of true mammals – again start with serious evolution, experimentation and diversification into mid-sized to large types living in most ecological niches.
