The following is my translation of an article called: Der Stammbaum der Nashörner von Anon. It appeared in a German popular science magazine, Kosmos Handweiser für Naturfreunde 1913, Heft 8, Seiten 282-287.
You really should see the wonderful illustrations accompanying the original article, but you won't be able to do so here. Get your own copy or draw some. At certain points, some readers will probably become bewildered by the numerous specific names. It happened to me, and the best cure is not to worry too much about it. I'm not aware of any previous translation.
Trevor Dykes.

The family tree of the rhinoceroses by Anon
A fact, which is frequently found in animal life, is the happenstance that animals of different types, whose origins can hardly be close with each other, are nevertheless often discovered together. An ideal example of this is provided by the families of elephants and rhinoceroses. In almost all geological strata which yield elephants are also found the skeletal parts of rhinoceroses, and even in such a manner that a particular elephant will correspond with a particular rhinoceros. Along with Elephas antiquus we meet Rhinoceros merckii, while the mammoth is constantly accompanied by Rhinoceros tichorhinus. This relationship goes so deep, that it can even allow imprecise or poorly preserved remains to be assigned to a species, should one have ascertained the genus of the other. When the remains of a single mammoth were found in a clay trench at Starunia, the body of a Rhinoceros tichorhinus was also discovered next to it.

It need not be said that this frequently makes the work of paleontologists easier. Therefore, it is of great interest to know more about the family trees of both animal groups. This has already been attempted from various parties for the elephants; the presentation by Dr Scheinger in the third edition of Kosmos, for example, provides a general summary of prevailing views.

One could think that it must be simple to also produce a family tree for rhinoceroses. At the first glance, this would appear to be child's play, as one apparently only needs to match the corresponding representative of the rhinoceros lineage to that of the appropriate elephant line (we see the relevant representatives for the Diluvian period above, and even Deinotherium can be matched with Rh. pachygnathus). The actual story is not quite as simple as that. Later, we will see this from the more detailed table provided by the Frenchman, Gaudry, that it is not, as for elephants, a simple chain of points forming a row and then, later, branching lines, but rather we find that rhinoceroses built separate lines from the beginning, and collectively were forerunners of a new species. (Additional note: I can't find anything wrong with my translation, so perhaps the original sentence didn't make sense!)

The external appearance might lead one to assume that the rhinoceroses are related with dinocertans, arsinotherians and titanotherians, which were also bearers of two or more horns. This is not the case, as those animals are closer allies of the pig, the tapir and the horse. This classification seems remarkable at first, and we also have ancestral rhinoceroses reminiscent of hippopotamuses, which also happen to be more closely related with pigs, and others which can lead one to consider whether or not they might perhaps have something to do with plump ponies. The original speed of the latter is still retained today by our modern rhinoceros, although one can only be convinced of that in the freedom of nature and not in a zoo. This makes it all the more difficult to discover rhinoceroses, as they lack a distinguishing characteristic such as the trunks of elephants.

During the Eocene, an early stage of the Tertiary where we find, for the first time, that the mammals were ruling the Earth after having deposed the reptiles, we also encounter an animal called Lophiodon, and we must talk of it as being the ancestor of rhinoceroses and tapirs. This is also when an elephant ancestor, Moeritherium, appears in Africa, but Lophiodon is found in America and Europe. Its size varies between that of a pig and a rhinoceros. This four-legged animal had a long, low skull and the teeth were already strongly reminiscent of a rhinoceros; however, there is not yet any trace of a horn.

According to Gaudry, the famous Palaeotherium (I am omitting a few important intermediaries) leads us to the first real rhinoceros, the Aceratherium. (Additional note: 'The famous Palaeotherium is a very close relative of horses, so I don't understand the reasoning behind this. As it seems to derive from M. Gaudry, I suppose I could try asking him.) However, as this animal corresponds with later formations, the Miocene or, at the earliest, the end of the Oligocene, I will first introduce two rhinoceros families already present during the Eocene, but extinct by the Oligocene.

The first of these peculiar animal groups is that of the hyracodontids. The main representatives are the somewhat delicate Hyrachus with four-toed, and the Hyracodon with three-toed front feet. These long legged animals have slim builds and relatively lengthy flanks (? Hälfen), and this makes them look more like ancient horses than rhinoceroses. The construction of the skeleton is that of a tapir, but the skull and cheek teeth show they belong to the rhinoceroses.

The second sort is the amnyodonts. Again, the build of tooth and skeleton show the relationship with the rhinoceros; but these exceptionally plump animals had a skull which, according to Zettel, is reminiscent of that known from a bear. While they are already found during the Eocene of America and extinct there by the Oligocene, they first appear in the latter time in Europe and then immediately cease.

With these three entirely different families, we see that it is difficult to identify an original common type. One form, however, that has already been mentioned, Aceratherium of the Miocene, is certainly near to the original form of the genuine rhinoceroses, and perhaps it is one. As the name says, it is a hornless animal. It naturally seems odd that a hornless animal (which is what Aceratherium means) could belong to the rhinoceroses. However, the build of the whole skeleton, the skull and the dentition of the creature are those of a rhinoceros. At another point, we will meet an undoubtable rhinoceros, the American Teleoceras which, despite its horn, actually appears less of a rhinoceros. The aceratheriids were animals with a narrow nose bone. The front foot has three toes, but it also bears the remnants of a further short, thin digit.

The further development of rhinoceroses is especially well shown by the construction of the nose bone. We have first had the case of a thin, weak nose bone with no horn. With the later form, Rr. pachygnathus, that bone has thickened and finally, to an extreme case (Rh. tichorhinus) which had a particularly wide partition between the nostrils.

Given the enormous number of rhinoceroses, I will have to limit myself to mentioning only a few of the more important ones. I am including Gaudry's family tree to show the interrelationships of the different species. (Additional note: But I'm not including it with this translation. At this junction, I'm going to have a cup of coffee while readers scurry off to find pencils and paper.)

Here we see that the lineage (beginning with Lophiodon) leads, on the one side, to Lophiodon rhinoceroides and, on the other, to Palaeotherium and Aceratherium guadryi. But already, with the next form of Aceratherium, which was discovered in Ronzon and given the beautiful name of Ronzotherium, we find both of these branches reunited again, and this is when the different rhinoceros types then begin to diverge. Whether we should place the above mentioned amnyodonts and hyracodonts quite here or there in this diagram, or have them as a parallel lineage or and end branch (starting from somewhere near Lophiodon), is open to discussion. With this presentation, which is in no way complete, I have added the American forms of Rh. megalodus and Telecocerus fossiger, which were unknown to Gaudry. For the purposes of easier comprehension, I have used the familiar name of Rhinoceros extensively, although today's literature contains a great number of sub-names. Without going into this in detail, I would simply like to state that only the living Indian form is actually called Rhinoceros, while the two-horned African rhinoceros is named Diceros.

Starting with Aceratherium lemanense, the line divides into two branches. One led to the development of the aceratherians, whereas the other branch is the direct lineage to Rh. sehleiermacheri via Rh. sansaniense. At this juncture comes another division. The rhinoceroses this gave rise to are discussed for us in terms of geography.

Australia, whose mammals had evolved to the stage of marsupials, naturally delivers no rhinoceroses but, in contrast, we have an entire developmental lineage of them in Asia involving Rh. sivalense to Rh. indicus or unicornis on the mainland of India, and Rh. sondaicus in Java. Today, we find Rh. (Ceratorhinus) sumatense in Sumatra, which is derived from the Miocene species of Rh. platyrhinus and Rh. simorrense. The Indian forms only have a single horn while the Sumatran rhinoceroses are adorned with two.

In Africa, we still have two species but, unfortunately, the keitloa or Black rhinoceros (Diceros) and the somewhat more common African Rh. bicornis are both close to extinction. The keitloa is a direct descendant of Rh. pachygnathus, so we can differentiate the transitional stages between the original form of Rh. megarhinus and Rh. leptorhinus. Rh. pachygnathus itself is the species connecting the African animal, via Rh. megarhinus, with our European representatives. It was as common in the Miocene of Greece as its ancestor, Rh. schleiermacheri, was in Germany; the latter is also found somewhat later in Greece. What we have here is an example showing that the same species can live in two different environments, and develop into adapted forms. While one moved further south away from the increasing cold and is today in Africa, the other remained in Germany, and even migrated, after developing its thick, insulating wool hair coat, into the Ice Age cold of Siberia. The species discovered in Italy, Rh. etruscus, which developed from Rh. megarhinus, provides the second of the most famous European forms. Rh. merckii, a slim and long-legged animal, lived in a somewhat milder climate. Its front horn was not as strongly curved as for Rh. ticorhinus, rather it slanted more to the front. The already mentioned Rh. tichorhinus or antiquus spread out after the extinction of the former. Discoveries made in Starunia and the Ozakerit trench of splendidly preserved bodies in Siberian ice show this animal, as with Rh. merckii and its African relatives, also had two horns, and the front one was significantly the longer. It had a length of about 1.25m and sat on a 75cm long skull. As already said, this horn had an especially strong dividing wall of the nose. Contrary to the earlier opinion that Siberian rhinoceroses broke through crevices in glaciers and were thus preserved, the opinion of today more usually holds they were buried by snow storms. The snow was then further frozen due to rain and melt water re-freezing, and that ice is what kept the bodies so well preserved.

In both Siberia and Rhein-Hessen we find an animal which, as for Rh. antiquus, lived alongside of people, and was the origin for the legend of the unicorn; the Elasmotherium. It is a rhinoceros that had only one horn, and this was on the forehead rather than the nose. The natives of Siberia today still talk of the black, one-horned bulls and their terrible savageness. In their view, it is ridden by the great ice giant who drove our ancestors out of Eden. This is a wonderful mixture of truth and poesy. Our original Germans had perhaps correctly recognised similarities with the horse, and the stylized art of the Middle Ages used this source to create the animal in the English coat of arms, which has the head of a horse and a narwhale tooth as a horn.

America, the latest discovered continent, has yielded the aforementioned old forms of Hyracodon and Amnyodon, and we also naturally find a large number of further rhinoceros species there. In this regard, I will limit myself to mentioning only one of the more remarkable ones, namely Teleoceras. This animal comes from the Pliocene and is also descended from Rh. aurelianense. If it did not have a horn on its skull along with its genuine rhinoceros dentition, then the build of its body, with its very short extremities, could perhaps be held as being more in line with a hippopotamus.

Our prehistoric people in Europe did not miss the opportunity to paint their contemporary, Rh. antiquus, on the walls of their caves; and it can be seen that these examples of painting techniques correspond with the outlines of the animals, as is the case for paintings by our contemporary Bushmen of their African prey animals.

Unfortunately, with our modern methods of hunting, we have nothing more than the senseless extermination of whole animal groups for the sake of a narrow profit, which is carried on in a similar way for both the rhinoceros and elephants. Of an entire family, which was previously so varied and numerous, as few other instances were, we are now left with only 5 species. Let us hope that, on the one hand, these interesting animals will be protected by stricter hunting laws than has so far been the case and, on the other, they will defend their own lives as energetically as possible as, according to the reports of Schilling, our African explorer, they are as dangerous opponents as any predators.

An index of more of my translations of old Kosmos articles can be found at:

Kosmos Translations Archive

A number of Mesozoic (and post-Mesozoic) location summaries can be found at Localities.