Crown-Antlered Sabre Deer
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!"
Back in time we go, to the Miocene again! I hope you don't mind all this palaeontology. For me, it's fascinating to learn where everything alive today actually came from. You can't understand the phenomenon of life without going into its evolution. And I'm doing reconstructions of species that often have been greatly neglected in palaeo-art.
I've now dealt fairly extensively with the Bovidae, so now let us look at the other major group of even-toed hoofed mammals – the deer, or Cervidae. While bovids occur in Europe, Africa, Asia and North America, deer are absent from sub-Saharan Africa and present in South America. The main difference between deer and bovids is that bovids have permanent, unbranched, bony horn-cores overlain by a sheath of horn; deer have branched, non-permanent antlers that grow anew each season and then are shed. As the antlers start to grow, they're covered in skin called velvet; when the antlers are fully grown, the velvet sloughs off to reveal the bare bone. At the end of the season, the bone develops a natural line of weakness near the base where it then soon breaks off.
Actually, not all deer have antlers like this. A few kinds have small, reduced antlers without tines. Some lack antlers entirely. But the above describes most modern deer. While mostly it's only the males that have antlers, female reindeer or Caribou have antlers as well. Antlers are, when you think about it, some of the weirdest things seen in nature. They also represent some of the fastest-growing tissues in any kind of animal, with even the huge antlers of reindeer or moose growing to full size in a six month period. But how did they evolve?
The ancestry of the deer family goes back to small, hornless, browsing, forest-living animals that lived in the Oligocene period. This kind of animal was actually the ancestor of bovids, musk deer, pronghorns and giraffes as well as of deer. By the early Miocene, about 20 million years ago, the first antlered deer had appeared. But their antlers were somewhat different from those of modern deer. The origin of deer seems to lie close to the Palaeomerycidae family, which I've treated extensively in this column. That means their antlers must have started as simple, bony outgrowths of the skull. But quite early on, in the deer these horns started branching at the tips in all sorts of weird ways.
Lagomeryx ('rabbit deer') is one of the earliest deer known, its fossils dating to about 18 million years ago. Several different species are recognized, from the size of a rabbit up to about the size of a roe deer. Its 'antlers' were quite small, with the one I illustrate here actually having antlers at the upper size limit of the genus; most had very short antlers with tiny prongs. The prongs, five to seven in number per antler, were all branched off the tip of the antler in a crown-like formation. It is this crown-antler formation that defined the group I'm discussing here. All of them are close to Lagomeryx, and they're sometimes classified as a subfamily, the Lagomerycinae, of the deer family. Sometimes they're even classified in a family of their own, the Lagomerycidae. All were rather small, with the crown-tipped antlers, and with quite large, sabre-like canine teeth. These long canine teeth were a common feature in many early deer-like animals; today it is still found among some deer and also the musk deer. Animals without antlers could use these sharp tusks to defend themselves; nevertheless, early deer for quite a while kept the sharp fangs even while developing the first beginnings of antlers. Despite the fangs, they were herbivores, and likely browsers of herbs, shrubs and trees in forests or woodlands.
The genus Lagomeryx existed from about 18 to 13 million years ago. It branched into two further genera: Paradicrocerus, which lived from about 17.5 to 11 million years ago, and Stephanocemas, which is known to have existed from 15 to 12 million years ago. Lagomeryx and Paradicrocerus fossils have been found both in Europe and in Asia, but Stephanocemas proper seem to have been purely Asian, being found from Kazakhstan to Mongolia to Thailand. It was the largest of the three, while still being small for a deer.
Where the prongs of Lagomeryx were like short fingers at the tips of the pedicels, Paradicrocerus had a cup-like crown formation at the tips of its antlers, with sharp points pointing upwards. Stephanocemas had the most elaborate antlers of the group, with a flat, broad 'palm' bearing flattened, outward-pointing prongs. These flat antlers were borne at the tips of fairly short pedicels; the palm-structure reached a length of about 20 cm in the largest species illustrated here, Stephanocemas palmatus.
In all these early deer, the antlers were bony outgrowths of the skull. The question is, just how similar were they to the antlers of modern deer? Modern antlers form a conspicuous 'burr' on the pedicels (the 'stalks' of the antlers) where the antler breaks off every year and from where a antler grows out. These early deer do not have a clear burr. But there are indeed signs that Stephanocemas and Lagomeryx did occasionally shed their antlers. In Lagomeryx there are even signs that after each casting, the new antlers developed additional prongs. But it might not have been a yearly thing. In my next article, I'll be looking at one of the first kinds of deer for which there are clear signs of regular antler-shedding. These small, crown-antlered deer represent an early and rather weird experiment in antler configuration. The following kinds of deer looked more like the ones we know today, but there were among them a few more truly weird ones which I hope to cover here soon enough.