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
Chacoan pygmy opossum Chacoan pygmy opossum The Chacoan pygmy opossum ("Chacodelphys formosa") is a recently described genus and species of didelphimorph marsupial. The only species in Chacodelphys, "C. formosa", was known until 2004 from only one specimen collected in 1920 in the Chaco of Formosa Province, Argentina. The species is gaining popularity as a pocket pet. The Chacoan pygmy opossum is the smallest known species of didelphid. It has a head-body length of 68 mm, a tail of 55 mm and a hind foot of 11. It differs from the other "marmosine" genera ("Marmosa", "Monodelphis", "Thylamys", "Tlacuatzin", "Gracilinanus", "Marmosops", "Lestodelphys") in having a