I am going to give another wag of the finger, this time to Scientific American. They posted a number of paintings of reconstructions of various extinct “horses” in a picture gallery titled “Ancient Miniature Horses”, which includes an entry for the famous “dawn horse”, Hyracotherium.
However, the problems lies not in the painting, which is probably a reasonable guesstimate of what Hyracotherium might have looked like in life but rather with the blurb of information included with the painting:
Hyracotherium This genus of small early horse roamed the early woodlands of Asia, Europe and North America some 55 million to 45 million years ago. It was already larger than Sifrhippus, weighing about 22.7 kilograms. But when Richard Owen first discovered Hyracotherium in 1876, it was so diminutive that he thought it was some unknown hyrax species, a group of extant mammals that live in Africa and the Middle East.
No, no, no, a thousand times no! It is bad enough when creationists claim that Hyracotherium is merely a hyrax (rather than a ancestral horse) and claim that Richard Owen thought so as well but to have a venerable science publication like Scientific American falling into the same pit of misinformation is extremely vexing.
Regular readers of this blog will have to forgive the repetition from earlier posts (see links below) on the subject of Hyracotherium, but until this information becomes common knowledge (at least among those who should know better), I am going to keep hammering at it.
Yes, Richard Owen did indeed name the fossil Hyracotherium and this does literally mean “hyrax-like beast”, however he did not intend this to be taken to mean it was in fact a species of hyrax or even that it was all that similar to a hyrax. In fact he specifically repudiated the idea of a close resemblance in the very paper in which he first described and named Hyracotherium:
The general form of the skull was probably intermediate in character between that of the Hog and the Hyrax. The large size of the eye must have given to the physiognomy of the living animal a resemblance to that of the Hare and other timid Rodentia.
Without intending to imply that the present small extinct Pachyderm was more closely allied to the Hyrax than as being a member of the same order, and similar in size, I propose to call the new genus which it unquestionably indicates, Hyracotherium, with the specific name leporinum. (Owen 1841, emphasis mine)
The “Order” Owen is referring to here is “Pachydermata” (after Cuvier) which is no longer considered a valid taxon. It included elephants (as should be obvious from the name), a variety of even-toed ungulates (cows, deer, hippos, pigs etc.), odd-toed ungulates (tapirs, rhinoceros and horses), as well as the hyraxes.
Now, if Owen’s specifically stating his naming of Hyracotherium wasn’t intended to imply either identity or even close similarity between the genus and hyraxes was insufficient to make my case, further evidence can be found in a paper Owen wrote a few years later in which he attempted to refine Georges Cuvier’s (the “father” of vertebrate paleontology) classification of “Pachyderms” (Owen 1848). In this paper Owen divided the “ungulatata” up into three different groups, the Proboscidia (elephants), the Artiodactyla (even-toed), and Perissodactyla (odd-toed) and he gave a list of examples of each of these and here is where it gets real interesting (ibid. p.139, color added for emphasis):
As you can see in this paper Owen placed Hyracotherium among the Artiodactyls (even-toed ungulates) and the hyraxes into a completely different sub-group, the Perissodactyla (odd-toed ungulates). If anything this would imply that he thought hyraxes and horses were more similar to each other than either was to Hyracotherium. Of course Owen was mistaken in his classification but he only had a crushed partial skull and a jaw fragment of Hyracotherium to go on so we can be forgiving.
I should probably edit the Wikipedia entry myself to perhaps avoid having to write this again in the future…
[A link to this post has been posted at scientificamerican.com]
Owen, Richard (1841) “Description of the Fossil Remains of a Mammal (Hyracotherium leporinum) and of a Bird (Lithornis vulturinus) from the London Clay.” Transactions of the Geological Society of London, Series 2, VI: 203-208, 1 plate
Owen, Richard (1848) “Description of Teeth and portions of Jaws of two extinct Anthracotheroid Quadrupeds (Hyopotamus vectianus and Hyop. bovinus)…”, The Quarterly Journal of the Geological Society of London 4(1):103-141
Earlier posts regarding Hyracotherium: