Discovery and taxonomy
skeleton with a H. amphibius
The Malagasy hippopotamus was first described in the mid-19th century by Alfred Grandidier, who unearthed nearly 50 individual hippos from a dried-up swamp at 'Ambolisatra' (thought to be Ambolisaka, near Lake Ihotry), a few miles from the Mozambique Channel. As many as four different species of hippopotamus were subsequently identified by various researchers. In a careful revision of the fossil record of the Malagasy hippos, Solweig Stuenes concluded that there were only two species of hippopotamus which she classified as Hippopotamus lemerlei and Hippopotamus madagascariensis. In 1990, Faure and Guerin discovered a distinct third species of hippo, which they named Hippopotamus laloumena. In a review of Stuenes work, Harris suggested that Hip. madagascariensis had much in common with the extant pygmy hippopotamus of West Africa. Since the extant pygmy hippopotamus was placed in the genus Hexaprotodon, he used the name Hex. madagascariensis. Some taxonomists, however, consider the modern pygmy hippo to belong to the genus Choeropsis, so this species may also be classified as C. madagascariensis.
The fossil record of the Malagasy hippopotamus is extensive. At least seven hippopotamus bones show unequivocal signs of butchery, suggesting that they survived until humans arrived on Madagascar. The evidence of humans butchering the hippos also suggests their extinction may have been, in part, due to humans. Despite the discovery of many fossils, the hippos of Madagascar are not very well studied, perhaps because researchers are interested in some of the more exotic megafauna of Madagascar, such as the giant lemurs and the elephant birds.