Three species of recently extinct Hippopotamus have been described from Madagascar.
- ‘dwarf’ species, Hippopotamus madagascariensis, featured here, is known from the island’s central highlands.
- 'dwarf' species, Hippopotamus lemerlei from the island’s coastal lowlands,
- more amphibious
- expresses marked sexual dimorphism.
- A third species, Hippopotamus laloumena, from Mananjary on the East coast of Madagascar,
- known only from a mandible and some foot bones,
- close in size to the smallest Hippopotamus amphibius
- initially described as a subspecies of Hippopotamus amphibius.
The precise timing and number of immigration events that led to the colonisation and diversity of hippopotamus species on Madagascar is not known. However, the founder ancestor or ancestors were derived from the genus Hippopotamus.
H. madagascariensis (NHM M7093): superorbital margin thin above eye socket.