It has long been believed in evolution that whales and hippos are related, but this has only been confirmed about 20 years ago. A few days ago there has been another update to this evolutionary story. Scientists have discovered a new missing link between the hippo and the whale. Starting in 1994 there have been expeditions led by Meave Leakey in Kenya looking for this missing link. Leakey found the first tooth in 1994, and then returned to Kenya in 2007. The teeth belong to an extinct species of mammals called the anthracothere, ancestor of whales, hippos, cows, pigs and goats. It is believed that the ancestor of the hippo swam the distance from Asia and was the first of their kind to arrive in Africa around 33 million years ago.
Recently a new member of the anthracothere species has been found in Kenya. This creature is a distant relative of the modern day hippo. This creature is being called the Epirigenys lokonensis, meaning the original hippo of Lokone, with Lokone being the region that they found the teeth. The Epirigenys lokonensis was smaller than the modern hippo only being about the size of a sheep and weighing less than 250 pounds. Meanwhile the modern hippo weighs anywhere from 3,000 to 6,000 pounds.
This link was made because of the shape of the teeth of the organism found. Many mammal teeth are distinct from that of others, having evolved to the food sources that they use. Hippos and Epirigenys lokonenis share a similar pattern on their teeth, they both have a similar 3 pronged maple leaf pattern on the top. This shape is unique to the hippo.
Before teeth were used to look at their evolution people believed that the hippo and the whale shared no common ancestors. People believed that they we closely related to the pig, due to their similarities in shape. 200 years ago scientists misinterpreted the shape of the teeth and still believed that the pig was the closest relative. While teeth are helpful things to look at when trying to look at evolution, they cannot be the only source. Teeth are the pieces that are preserved the longest, during that time they are subject to change from their environment. At this time despite teeth being the only remains found there is no denying it, whales are the hippos closest relative.
-Madison Boone (Group A)