A new Arican miocene gibbon-like genus, Dendropithecus (hominoidea, primates) with distinctive postcranial adaptations: its significance to origin of hylobatidae.

The small, common apes of the Miocene deposits of East Africa previously assigned to two species of one genus, Limnopithecus, have been shown to differ at the generic level in both dental and postcranial features. The prior and smaller of the two species (the genotype of Limnopithecus) somewhat resembles in dental morphology African dryopithecines of subgenus Proconsul, while the larger and later described species more nearly resembles European Pliopithecus in dental details but is strikingly different from the latter in comparable postcranial bones. A new genus, Dendropithecus, is here proposed for Limnopithecus macinnesi Clark and Leakey, 1950. Numerous associated postcranial bones and dentitions of Dendropithecus macinnesi were found in a block of red limestone by L.S.B. Leakey in 1948 on Rusinga Island, Lake Victoria, Kenya. These bones make it one of the best known Miocene apes and show clearly that it had advanced away from other Miocene apes in its higher degree of development of suspensory or arm swinging postcranial adaptations. Thus, among known Miocene ape species it has the greatest demonstrated potential to be near the line of ancestry of the modern gibbon and siamang.