About five million years ago – and without any human intervention – animals of the genus Chilotherium became extinct. You can imagine them like rhinos, whose ancestors they are, but they didn’t have a horn. Not on the nose and not further back towards the forehead, where some modern rhinoceros have their second horn. With their short legs and bulging stomach, representatives of Chilotherium would certainly have lost a race against their descendants. Some of today’s rhino species can run 55 kilometers per hour. Nevertheless, their little legs carried them far: they lived in southeastern Europe and Asia.
However, when researchers around the world find skulls or bones that they want to match with this genus, they have a problem. They are missing the reference for two species. This is the name given to finds that serve as the basis for the description of a species, the flagship of a species. The Chilotherium reference fossils, which were once stored in the Bavarian State Collection for Paleontology and Geology (BSPG), have been lost and probably destroyed since the Allied bombing of Munich in April 1944. Since then there have only been a few illustrations of previous finds.
That’s why an international research team has now searched collections from museums in Germany, Austria, France, Greece and Switzerland for additional Chilotherium specimens. They found what they were looking for in the Museum der Natur Hamburg and the Senckenberg Research Institute and Natural History Museum in Frankfurt: There they discovered two fossil skulls of hornless rhinos, which they found in… Journal of Vertebrate Paleontology suggest as a new reference. This is “of utmost importance” for the paleontological community, says paleontologist Manon Hullot from the BSPG.
She has also searched museums for skulls or other finds, which is common practice. “We usually know what we’re looking for in advance, but there can be surprises.” Sometimes forgotten finds come to light during such forays: a fossilized egg was stored in a museum in Yingliang, southern China, for fifteen years. In it: a perfectly preserved fossil of an unhatched baby dinosaur, nicknamed Baby Yingliang. The legs are drawn up, hugged close to the body, the back is arched, the beak-like head is clamped between the toes. The curled posture is similar to that of bird embryos before they hatch. For researchers, the fossil, which is approximately 70 million years old, is evidence of the relationship between dinosaurs and birds.
Like the dinosaurs, three out of five of today’s rhino species that live in Africa and Asia are currently threatened with this fate. While the numbers of the African rhinos are slowly recoveringthere from Sumatran rhinoceros only have fewer than 50 animals left. This also has to do with their horn and the illegal hunting of it. Unlike the real horn that sheep or antelopes wear, or the antlers that adorn deer, the rhino’s antlers are not made of bones, but of glued and keratinized skin cells. Like human hair or nails, it grows throughout life.