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 monkeys (Platyrrhini) and Catarrhi ...

primate Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians (monkeys and apes, the latter including huma ...

s that lived in Late

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

and

Early Oligocene The Rupelian is, in the geologic timescale, the older of two ages or the lower of two stages of the Oligocene Epoch/Series. It spans the time between . It is preceded by the Priabonian Stage (part of the Eocene) and is followed by the Chatti ...

. Fossils have been found in

Myanmar Myanmar, ; UK pronunciations: US pronunciations incl. . Note: Wikipedia's IPA conventions require indicating /r/ even in British English although only some British English speakers pronounce r at the end of syllables. As John C. Wells, Joh ...

Thailand Thailand ( ), historically known as Siam () and officially the Kingdom of Thailand, is a country in Southeast Asia, located at the centre of the Indochinese Peninsula, spanning , with a population of almost 70 million. The country is bo ...

, and

Pakistan Pakistan ( ur, ), officially the Islamic Republic of Pakistan ( ur, , label=none), is a country in South Asia. It is the world's List of countries and dependencies by population, fifth-most populous country, with a population of almost 24 ...

. 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 Adapiformes is a group of early primates. Adapiforms radiated throughout much of the northern continental mass (now Europe, Asia and North America), reaching as far south as northern Africa and tropical Asia. They existed from the Eocene to the M ...

nor

omomyid Omomyidae is a group of early primates that radiated during the Eocene epoch between about (mya). Fossil omomyids are found in North America, Europe & Asia making it one of two groups of Eocene primates with a geographic distribution spanning h ...

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 , catarrhine monkeys, Old World anthropoids, or Old World monkeys, consisting of the Cercopithecoidea and apes (Hominoidea). In 1812, Geoffroy grouped those two groups together and established the name Catarrhini, "Old ...

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 com ...

and that they should instead be considered

Adapiformes Adapiformes is a group of early primates. Adapiforms radiated throughout much of the northern continental mass (now Europe, Asia and North America), reaching as far south as northern Africa and tropical Asia. They existed from the Eocene to the M ...

. 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 ''Amphipithecus mogaungensis'' ("ape-like creature of Mogaung", derived from the Ancient Greek , ' meaning "around" and ', ' meaning "ape") was a primate that lived in Late Eocene Myanmar. Along with another primate '' Pondaungia cotteri'', both ...

'' *'' Bugtipithecus inexpectans'' *''

Ganlea megacanina ''Ganlea'' is a fossil primate from central Myanmar, formerly known as Burma. Its age is about 38 million years, living during the late Eocene epoch. ''Ganlea'' belongs to the group of anthropoids (i. e. humans, apes and monkeys), and is in the f ...

'' *'' 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. Named after the circus showman P. T. Barnum, he discovered the first documented remains of ''Tyrannosaurus'' during a career ...

was prospecting along areas of Pondaung

Sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) ...

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 Edwin Harris "Ned" Colbert (September 28, 1905 – November 15, 2001)O'Connor, Anahad ''The New York Times'', November 25, 2001. was a distinguished American vertebrate paleontologist and prolific researcher and author. Born in Clarinda, Iowa, he ...

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 of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...

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 Eosimians 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, dog teeth, or (in the context of the upper jaw) fangs, eye teeth, vampire teeth, or vampire fangs, are the relatively long, pointed teeth. They can appear more flattened however ...

, but it had tiny

incisor Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, whe ...

References

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