The Amphipithecidae were

simian The simians, anthropoids, or higher primates are an infraorder (Simiiformes ) of primates containing all animals traditionally called monkeys and apes. More precisely, they consist of the parvorders New World monkey, Platyrrhini (New World mon ...

primate Primates is an order (biology), order of mammals, which is further divided into the Strepsirrhini, strepsirrhines, which include lemurs, galagos, and Lorisidae, lorisids; and the Haplorhini, haplorhines, which include Tarsiiformes, tarsiers a ...

s that lived in Late

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

and

Early Oligocene The Rupelian is, in the geologic timescale, the older of two age (geology), ages or the lower of two stage (stratigraphy), stages of the Oligocene epoch (geology), Epoch/series (stratigraphy), Series. It spans the time between . It is preceded b ...

. Fossils have been found in

Myanmar Myanmar, officially the Republic of the Union of Myanmar; and also referred to as Burma (the official English name until 1989), is a country in northwest Southeast Asia. It is the largest country by area in Mainland Southeast Asia and has ...

Thailand Thailand, officially the Kingdom of Thailand and historically known as Siam (the official name until 1939), is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. With a population of almost 66 million, it spa ...

, and

Pakistan Pakistan, officially the Islamic Republic of Pakistan, is a country in South Asia. It is the List of countries and dependencies by population, fifth-most populous country, with a population of over 241.5 million, having the Islam by country# ...

. The limited fossil evidence is consistent with, but not exclusive to, arboreal quadrupedalism. In other words, the species may have moved about in trees on four legs, but not with regular leaping as seen in later simians. What little is known suggests that they are neither adapiform nor omomyid primates, two of the earliest primate groups to appear in the fossil record. Deep mandibles and mandibular molars with low, broad crowns suggest they are

s, a group that includes monkeys, apes, and humans, but are not within the two major extant groups of simians, the

Catarrhini The parvorder Catarrhini (known commonly as catarrhine monkeys, Old World anthropoids, or Old World monkeys) consists of the Cercopithecoidea and apes (Hominoidea). In 1812, Geoffroy grouped those two groups together and established the name ...

and Platyrrhini. Most scholars place them in the

s. However, some scholars suggest that their similarities to simians is the result of

convergent evolution Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last comm ...

and that they should instead be considered Adapiformes. According to Beard et al., '' Siamopithecus'' is the most basal form of amphipithecid. They vary in size from 6–7 kg (''Siamopithecus'' and '' Pondaungia''), to 1–2 kg ('' Myanmarpithecus''), with '' Bugtipithecus'' being even smaller. A number of scholars speculate that the teeth and jaws of the larger Amphipithecidae indicate that they fed on seeds and fruit with hard exteriors, whilst smaller species such as ''Myanmarpithecus'' ate soft fruit. ''Pondaungia'' and ''Amphipithecus'' are now considered by scholars to be part of the same genus.

Species

*'' Amphipithecus mogaungensis'' *'' Bugtipithecus inexpectans'' *'' Ganlea megacanina'' *'' Myanmarpithecus yarshensis'' *'' Pondaungia cotteri'' *'' Siamopithecus eocaenus''

Discoveries

When fossil hunter

Barnum Brown Barnum Brown (February 12, 1873 – February 5, 1963), commonly referred to as Mr. Bones, was an American paleontologist. He discovered the first documented remains of ''Tyrannosaurus'' during a career that made him one of the most famous fossil ...

was prospecting along areas of Pondaung

Sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

in 1923, he discovered a mandible with three teeth (''Amphipithecus mogaungensis''). He did not recognise the significance of his find until 14 years later, when Edwin H. Colbert identified the fossil as a new species of primate and the earliest known simian. In May 2005, the discovery of dozens of new primate fossils, mainly single teeth, in the Bugti Hills of

, was announced. They were recognised as belonging to three new species, including ''Bugtipithecus inexpectans'', dated back to the

Oligocene The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...

some 30 million years ago. (The other new species were in the

Eosimiidae Eosimiidae is the possible family of extinct primates believed to be the earliest simians. Taxonomy When they were discovered, the possibility that eosimiids were outside and ancestral to simians was considered (Culotta 1992), but subsequent ...

family). In July 2009, the discovery of ''Ganlea megacanina ''in the late-middle Eocene Pondaung Formation in central

was announced. It is smaller than ''Pondaungia'', but larger than ''Myanmarpithecus''. Its robust dentary includes a notably large lower

canine tooth In mammalian oral anatomy, the canine teeth, also called cuspids, dogteeth, eye teeth, vampire teeth, or fangs, are the relatively long, pointed teeth. In the context of the upper jaw, they are also known as '' fangs''. They can appear more f ...

, but it had tiny incisors.

References

{{Taxonbar, from=Q30094061 Primate families Prehistoric mammal families