The phylogenetic split of the superfamily

Hominoidea Apes (collectively Hominoidea ) are a clade of Old World simians native to sub-Saharan Africa and Southeast Asia (though they were more widespread in Africa, most of Asia, and as well as Europe in prehistory), which together with its sister g ...

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

Miocene The Miocene ( ) is the first epoch (geology), 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 mea ...

, roughly . Hylobatidae has four gibbon genera ('' Hylobates'' with 9 species, ''

Hoolock The hoolock gibbons are three primate species of genus ''Hoolock'' in the gibbon family, Hylobatidae, native to eastern Bangladesh, Northeast India, Myanmar, and Southwest China. Description Hoolocks are the second-largest of the gibbons, after ...

'' with 3 species, ''

Nomascus ''Nomascus'' is the second-most speciose genus of gibbons (family Hylobatidae). Originally, this genus was a subgenus of ''Hylobates'', and all individuals were considered one species, ''Hylobates concolor''. Species within ''Nomascus'' are char ...

'' with 7 species and ''

Symphalangus The siamang (, ; ''Symphalangus syndactylus'') is an arboreal, black-furred gibbon native to the forests of Indonesia, Malaysia, and Thailand. The largest of the gibbons, the siamang can be twice the size of other gibbons, reaching in height, a ...

'' with only 1 species) containing 20 different species. Hominidae has two subfamilies,

Ponginae Ponginae , also known as the Asian hominids, is a subfamily in the family Hominidae. Once a diverse lineage of Eurasian apes, the subfamily has only one extant genus, '' Pongo'' (orangutans), which contains three extant species; the Sumatran oran ...

(orangutans) and

Homininae Homininae (), also called "African hominids" or "African apes", is a subfamily of Hominidae. It includes two tribes, with their extant as well as extinct species: 1) the tribe Hominini (with the genus ''Homo'' including modern humans and numerou ...

(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 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 ...

(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, in strata from the Middle Pleistocene. Although the three hoo ...

'' 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 Incomplete lineage sorting, also termed hemiplasy, deep coalescence, retention of ancestral polymorphism, or trans-species polymorphism, describes a phenomenon in population genetics when ancestral gene copies fail to coalesce (looking backwards i ...

. 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