The phylogenetic split of the superfamily Hominoidea (apes) into the

Hylobatidae Gibbons () are apes in the family Hylobatidae (). The family historically contained one genus, but now is split into four extant genera and 20 species. Gibbons live in subtropical and tropical rainforest from eastern Bangladesh to Northeast India ...

(gibbons) and

Hominidae The Hominidae (), whose members are known as the great apes or hominids (), are a taxonomic family of primates that includes eight extant species in four genera: '' Pongo'' (the Bornean, Sumatran and Tapanuli orangutan); ''Gorilla'' (the ea ...

(great apes) families (also dubbed "gibbon–human last common ancestor", GHLCA) is dated to the early

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...

, roughly . Hylobatidae has four gibbon genera (''

Hylobates The genus ''Hylobates'' is one of the four genera of gibbons. Its name means "forest walker", from the Greek (, "forest") and (, "one who treads"). It was once considered the only genus, but recently its subgenera (''Hoolock'' ormerly ''Bun ...

'' with 9 species, '' Hoolock'' with 3 species, '' Nomascus'' with 7 species and '' Symphalangus'' with only 1 species) containing 20 different species. Hominidae has two subfamilies, Ponginae (orangutans) and Homininae (African apes, including the human lineage).

Evolutionary history

A 2014 whole-genome molecular dating analysis indicated that the gibbon lineage diverged from that of great apes (Hominidae) around 17 million years ago (), based on certain assumptions about the generation time and mutation rate. The extinct ''

Bunopithecus sericus ''Bunopithecus'' is an extinct genus of primate represented by one species, ''Bunopithecus sericus'', a gibbon or gibbon-like ape. Its remains were first discovered in Sichuan, China China, officially the People's Republic of China (PRC) ...

'' was a gibbon or gibbon-like ape. Adaptive divergence associated with chromosomal rearrangements led to rapid radiation of the four genera within the Hylobatidae lineage between about 7 to 5 Mya. Each genus comprises a distinct, well-delineated lineage, but the sequence and timing of divergences among these genera have been hard to resolve due to radiative speciations and extensive incomplete lineage sorting. Recent coalescent-based analysis of both the coding and noncoding parts of the genome suggests that the most likely sequence of species divergences in the Hylobatidae lineage is (Hylobates, (Nomascus, (Hoolock, Symphalangus))). Hominoidea lineage

Appearance and ecology

Because fossils are so scarce, it is not clear what GHLCA looked like. A 2019 study found that the species was "smaller than previously thought" and about the size of a gibbon. It is unknown whether GHLCA was tailless and had a broad, flat rib cage like their descendants. But it is likely that it was a small animal, probably weighing only . This contradicts previous theories that they were the size of chimpanzees and that apes moved to hang and to swing from trees to get off the ground because they were too big. There might have been an arms race in brachiating to reach the best food. Also, the Hominidae, which came later, were smaller than their ancestors, which is contrary to normal evolution where animals get larger over their evolutionary development.

Evolutionary history

Appearance and ecology

References

See also