Ed Yong has an interesting story about Toxodon on the blog Phenomena over at National Geographic. Seems the animal never really had a comfortable place in the tree of life. But now, using molecular biology techniques on old bones, scientists were able to extract enough information from collagen molecules to place Toxodon near perissodactyls - odd-toed hoofed mammals like rhinos, tapirs, and horses.
“Toxodon is perhaps one of the strangest animals ever discovered,” wrote Charles Darwin, a man who was no stranger to strangeness. He first encountered the creature in Uruguay on November 26th, 1834. “Having heard of some giant’s bones at a neighbouring farm-house…, I rode there accompanied by my host, and purchased for the value of eighteen pence the head of the Toxodon,” he later wrote.
The beast’s skeleton, once fully assembled, was a baffling mish-mash of traits. It was huge like a rhino, but it had the chiselling incisors of a rodent—its name means “arched tooth”—and the high-placed eyes and nostrils of a manatee or some other aquatic mammal. “How wonderfully are the different orders, at present time so well separated, blended together in different points of the structure of the toxodon!” Darwin wrote.
The original paper is in Nature.
