ANTLERED ELEPHANTS - OR UNLIKELY UINTATHERES?

'Antlered elephants' and other North American prehistoric fauna from the Eocene epoch in what is today Wyoming, USA, as depicted in William D. Gunning's book Life History of Our Planet (1881) (public domain)

Have there ever been antlered elephants? Not as far as we know – so how can the extraordinary illustration presented above be explained? The answer dates back to the intense rivalry between two eminent American fossil collectors, resulting in the so-called Bone Wars that galvanised 19^th-Century palaeontology, and focuses upon the subject of one of their most fervent bouts of competitive taxonomic classification – a long-extinct but spectacularly strange-looking group of huge ungulate mammals known as uintatheres.

Uintatheres have always held a special place in my childhood memories because the very first artistic reconstruction of a fossil mammal's likely appearance in life that I ever saw was of a Uintatherium – vibrantly depicted on one of the opening pages of my How and Why Wonder Book of Wild Animals (1962) that my mother bought for me when I was about 4 years old during the early 1960s. I read that poor, long-suffering book so many times and with such youthful enthusiasm that it eventually fell apart, but a replacement copy was soon purchased, which I still own today, so here is that wonderful, fondly-remembered illustration:

Uintatherium depicted by Walter Ferguson in The How and Why Wonder Book of Wild Animals (© Walter Ferguson/Transworld Publishers / inclusion here strictly on Fair Use/non-commercial basis only)

But what are – or were – uintatheres? Named after the mountainous Uinta region of Wyoming and Utah where their first scientifically-recorded fossils were uncovered, they belonged to the taxonomic order Dinocerata ('terrible horns'). This was an early group of extremely large, superficially rhinoceros-like ungulates (but possessing claws rather than hooves), which existed from the late Palaeocene to the mid-Eocene, approximately 45 million years ago. The males of its most famous, culminating members, the uintatheres (which existed during the mid-Eocene), bore no less than three separate pairs of blunt ossicone-like horns on their heads. These consisted of a rear pair arising from the parietal bones near the back of the skull, a middle pair arising from the maxillae or upper jaw bones, and a front pair arising from the nasal bones. Their function remains uncertain, but they may have been used for defence and/or for sexual display purposes. Also, their skull was very concave and flat in shape, and with very thick walls, thus yielding so restricted a cranial cavity that the brain was surprisingly small for such sizeable animals.

Today, two major genera of uintatheres are recognised – Uintatherium and Eobasileus (plus a few less well known ones, such as Tetheopsis) – which are very similar to one another morphologically, and are distinguished predominantly by way of certain differences in skull proportions, as delineated in the following diagram and table. These originate from the definitive work on uintathere taxonomy, North Carolina University palaeontologist Dr Walter H. Wheeler's comprehensive paper 'Revision of the Uintatheres', published in 1961 as Bulletin #14 of the Peabody Museum of Natural History, Yale University.

Skull proportions in uintathere genera (from Wheeler, 1961)

Also, whereas the skull of Uintatherium was relatively broad, with the parietal bones positioned some way in front of the occiput (the skull's rearmost portion), in Eobasileus the skull was long and narrow, with the parietal horns further back and therefore much closer to the occiput.

In addition to their horns, male uintatheres also possessed a very sizeable pair of downward-curving upper tusks (they were much smaller in females), protected like scimitars by bony scabbard-resembling lower jaw down-growths. Behind each of these two tusks was a noticeable gap (diastema), separating the tusk on each side of the upper jaw from that side's first premolars. In Uintatherium, the maxillary horns were positioned directly above the diastema in each side of the upper jaw, whereas in Eobasileus they were positioned further back, above the premolars.

Comparing the structure of a Uintatherium anceps skull at the Muséum National d'Histoire Naturelle in Paris, France (above) with that of an Eobasileus cornutus skull at the Chicago Field Museum (below) (public domain / © Dallas Krentzel/Wikipedia)

Uintatherium was a massive browsing ungulate, up to around 13 ft long, 5.5 ft tall, and up to 2 tons in weight. Only two species of Uintatherium are recognised today – North America's U. anceps (the most famous dinoceratan of all, formally named and described in 1872 by American palaeontologist Prof. Joseph Leidy), and China's more recently-recognised U. insperatus (named and described in 1981).

Only one Eobasileus species is nowadays recognised – E. cornutus, named by fellow American palaeontologist Prof. Edward Drinker Cope in 1872. This was the largest uintathere of all, and in fact the largest land mammal of any kind during its time on Earth, with a total length of around 13 ft, standing 6.75 ft high at the shoulder, and weighing up to 4.5 tons.

Eobasileus as depicted masterfully and majestically by Charles Knight (public domain)

Just over a century ago, however, a bewildering plethora of uintathere genera and species had been distinguished and named, due not so much to any taxonomic merit, however, but rather to the driven desire by two implacable fossil-collecting foes during the 1870s and 1880s to outdo one another in their febrile quest for palaeontological immortality and to destroy each other's scientific reputation, until their obsession eventually ruined both of them, socially and financially.

Their names? Othniel Charles Marsh (1831-1899), and Edward Drinker Cope (1840-1897).

Othniel Charles Marsh (left) and Edward Drinker Cope (right) (public domain)

After having been professor of vertebrate palaeontology at Yale University in New Haven, Connecticut, Marsh became the first curator at the Peabody Museum of Natural History at Yale University (the museum having been founded by his wealthy uncle, the philanthropist George Peabody). Conversely, Cope preferred field work to academic research, as a result of which he never held a major scientific post of any lengthy tenure, though he did become professor of zoology for a time at the University of Pennsylvania in Philadelphia, his home city.

Although they are most famous for their frenzied attempts to best one another in the description of new dinosaur species, Marsh and Cope also constantly challenged each another along similar lines in relation to their descriptions of new uintatheres. The regrettable, chaotic result was the creation not only of numerous new species but also of many new genera, several of which were named within the space of a single year, and all of which were unjustified, having been founded upon the most trivial, taxonomically insignificant of differences.

This sorry, farcical state of affairs is preserved today in the startling array of junior synonyms attached to the genus Uintatherium, including the nowadays long-nullified genera Dinoceras (coined by Marsh in 1872), Ditetrodon (Cope, 1885), Elachoceras (Scott, 1886), Loxolophodon (Cope, 1872), Octotomus (Cope, 1885), Tinoceras (Marsh, 1872), and Uintamastix (Leidy, 1872). Although I normally have little interest in abandoned names, I do feel a pang of regret for the loss of one particular example here – the wonderfully-named Dinoceras mirabile (synonymised with Uintatherium anceps), which was coined in 1872 by Marsh, and translates as 'marvellous terrible-horn' – a very evocative, accurate description of how this extraordinary beast would have looked in life.

Uintatherium as portrayed upon a postage stamp issued by Afghanistan in 1988, from my personal collection (© Afghanistan postal service / inclusion here strictly on Fair Use/non-commercial basis only)

But what has all (or any) of this to do with antlered elephants? I'm glad you asked! Because uintatheres were indeed so astounding in form, when their first fossils were discovered palaeontologists were by no means certain which creatures were their closest relatives, and how, therefore, they should be classified. Cope, who was particularly enthralled by them, was convinced that such huge ungulates must surely be related to elephants, and he even opined that they probably possessed a long nasal trunk like elephants plus a pair of very large, wide, elephantine ears, and that they should be housed with them in the taxonomic order Proboscidea, thereby conflicting yet again with Marsh's view (in 1872, Marsh had placed them within their very own order, Dinocerata). But that was not all.

Cope also speculated that their rearmost, parietal pair of horns may have been much larger than the other two pairs, possibly even branched and covered in velvet, thereby resembling the antlers of deer. And so, in various early reconstructions of their putative appearance in life, this is exactly how uintatheres were portrayed – as antlered, large-eared, trunk-wielding pachyderms, resembling the highly unlikely outcome of an equally improbable liaison between an elephant and a moose!

Eobasileus cornutus with elephant ears and trunk , from an August 1873 Pennsylvania Monthly article by Edward Drinker Cope (public domain)

True, there were certain less dramatic versions – one illustration (see above) that appeared in a Pennsylvania Monthly article from August 1873 by Cope concerning the uintathere species now called Eobasileus cornutus portrayed it with tall unbranched parietal horns rather than with parietal antlers (although they are still slightly palmate at their distal edges), but did gift it with an elephant's ears and trunk (as instructed by Cope). However, the two most (in)famous examples of this specific genre of reconstruction were rather more extreme, and both of them appeared in William D. Gunning's book Life History of Our Planet (1881). One of these is the following diagrammatic reconstruction:

Line diagram of a Uintatherium (spelt 'Uintahtherium' here) as an antlered elephant-like beast in Gunning's book (public domain)

Gunning's comparisons drawn between this remarkable creature and various modern-day animals were equally memorable, albeit decidedly fanciful in parts (notably its small brain allying it with the marsupials!):

"We are as astronomers taking the parallax of a distant star. The animal which roamed along the banks of that Wyoming lake is as far from us in time as the star in space. What is its parallax? what its place in the scheme of creation? The long, narrow head with skull elevated behind into a great crest, the molar teeth and arch of the cheek-bone are characters, which indicate relationship with the Rhinoceros. The absence of teeth in the premaxillaries points to the Ruminants. The vertical motion of the jaw points away from the Ruminants, towards the Carnivores. The great expansion of the pelvis, the complete radius and ulna, the shoulder-blade and the hind-foot, are characters which affiliate our animal with the Elephant. The diminutive brain would place it with the pouched Opossum.

"The horns on the maxillaries, the concavity of the crown, and the enormous side crests of the cranium are characters which remove the animal from all living types. We have found the ruins of an animal composed of Elephant, Rhinoceros, Ruminant, Marsu­pial, and a something unknown to the world of the living. Drawing an outline around the skeleton, we have a long head with little horns on the nose, conical horns over the eyes, and palmate horns over the ears, with pillar-like limbs supporting a massive body nearly eight feet high in the withers and six in the rump. Eliminating from its structure all that relates to the living, so many and such dominant structures remain that we cannot choose for it a name from existing orders. We will call it Uintahtherium [sic], which means, the Beast of the Uintah Mountains."

A pair of antlered elephantine uintatheres appeared in this same book's frontispiece illustration, but this time fleshed out rather than in diagrammatic form, as part of an Eocene panorama of North American mammals. The illustration in question opens this present ShukerNature post, and is also reproduced below, together with its original accompanying caption:

The frontispiece illustration of Gunning's book, featuring a pair of antlered uintatheres (public domain)

By the end of the 19^th Century, however, with many additional fossilised remains having been discovered in the meantime, palaeontological views regarding both the morphology and the taxonomy of the uintatheres had changed markedly. Cope's views concerniing them had been totally rejected in favour of Marsh's, thus promoting the belief still current today that these mammalian behemoths represented a lost ungulate lineage, unrepresented by (and unrelated to) any that are still alive in the modern world.

A rather more modern-looking Uintatherium as illustrated in the Reverend H.N. Hutchinson's book Extinct Monsters (1897)

So it was, for instance, that Uintatherium was illustrated in Extinct Monsters (1897) by the Reverend H.N. Hutchinson in much the same manner as it still is now, over a century later, shorn of its velvet-surfaced antlers and with only relatively short and blunt, unbranched horns in their stead, plus much smaller ears, and a conspicuous lack of any probiscidean trunk. The antlered elephant was no more – a most unlikely uintathere had soon become a non-existent fossil phantom blown swiftly away by a brisk, incoming breeze bearing new discoveries and new ideas borne from a new generation of researchers. 'Twas ever thus.

My How and Why Wonder Book of Wild Animals (1962), containing the first Uintatherium illustration that I ever saw as a child (© Transworld Publishers / inclusion here strictly on Fair Use/non-commercial basis only)