Pygmy hippopotamus the pygmy hippopotamus, are considered dwarf hippopotamuses, rather than pygmies. They are likely descended from a full-sized species of European hippopotamus, and reached their small size through the evolutionary process of insular dwarfism which is common on islands; the ancestors of pygmy hippopotami were also small and thus there was never a dwarfing process. There were also several species of pygmy hippo on the island of Madagascar (see Malagasy hippopotamus). Pygmy hippos share the same general form as a hippopotamus. They have a graviportal skeleton, with four stubby legs and four toes on each foot, supporting a portly frame. The
Pygmy marmoset a separate genus for the pygmy marmoset, as "Callithrix" is no longer paraphyletic. There are two subspecies described by Colin Groves of the pygmy marmoset: There are few morphological differences between these subspecies, as they may only differ slightly in color, and they are only separated by geographical barriers, including large rivers in Central and South America. The evolution of this species diverged in terms of body-mass from typical primates, with a high rate of body-mass reduction. This involves large decreases in pre-natal and post-natal growth rates, furthering the thought that pro-genesis played a role in the evolution of this