 paenungulata is a taxon that groups three extant mammal orders: proboscidea (including elephants), sirenia (sea cows, including dugongs and manatees), and hyracoidea (hyraxes). at least two more orders are known only as fossils, namely embrithopoda and desmostylia (desmostylians, however, have been placed in perissodactyla by a 2014 cladistic analysis). each of these extinct orders was as unique in its members' ways as the surviving orders. embrithopods were rhinoceros-like herbivorous mammals with plantigrade feet, and desmostylians were hippopotamus-like amphibious animals. their walking posture and diet have been the subject of speculation, but tooth wear indicates that desmostylians browsed on terrestrial plants and had a posture similar to other large hoofed mammals. of the five orders, hyraxes are the most basal, followed by embrithopods; the remaining orders (sirenians, desmostylians and elephants) are more closely interrelated. these latter three are grouped as the tethytheria, because it is believed that their common ancestors lived on the shores of the prehistoric tethys sea; however, recent myoglobin studies indicate that even hyracoidea had an aquatic ancestor. although morphological evidence continues to support the position of paenungulates with the ungulates, the molecular evidence suggests that paenungulata is part of the cohort afrotheria, an ancient assemblage of mainly african mammals of great diversity. the other members of this cohort are the orders afrosoricida (tenrecs and golden moles), macroscelidea (elephant shrews) and tubulidentata (aardvarks). == history == in 1945, george gaylord simpson, using traditional [[taxonomy (biology)|taxonomic techniq
Mammal_taxonomy Mammals_of_Africa