Lufengpithecus

Lufengpithecus Temporal range: Late Miocene PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Primates
Suborder:	Haplorhini
Infraorder:	Simiiformes
Family:	Hominidae
Tribe:	†Lufengpithecini
Genus:	†Lufengpithecus Wu, 1987
Species
See text

Lufengpithecus is an extinct genus of ape in the subfamily Ponginae. It is known from thousands of dental remains and a few skulls and probably weighed about 50 kg (110 lb).^[1] It contains three species: L. lufengensis, L. hudienensis and L. keiyuanensis.

Characteristics[]

Like Sivapithecus, Lufengpithecus had heavy molars and large canine teeth. The lower third premolars sometimes have a slight second cusp, denoting a shift from their principal role as cutting teeth in other ape species.^{[citation needed]}

While Lufengpithecus is generally considered to be a primitive pongine by most Western observers, Chinese scientists have noted a set of features that are more reminiscent of hominines. These include a broad interorbital distance, an "African" subnasal morphology, frontal sinuses, and a number of dental similarities. Also, basicranial and postcranial remains indicate it may have had adaptations for a significant degree of bipedalism. The ultimate position of Lufengpithecus in hominoid phylogeny requires more research.^{[citation needed]}

A single mandibular fragment with P4 and M1 from the site of in Sichuan, China, originally assigned to the genus Homo, has been argued to be similar to Lufengpithecus, suggesting the genus may have survived until as recently as two million years ago, possibly overlapping with both Gigantopithecus and ancient Pongo in the region.^[2] One of the original authors who assigned the Longgupo specimen to Homo now considers it to be a "mystery ape".^[3]

A possibly related species from Thailand was assigned to the genus Khoratpithecus under the specific name chiangmuanensis.^[4] The species is known only from teeth, which appear to be intermediate in morphology between Sivapithecus and modern orangutans. The species lived about 10 million years ago and may have been the ancestor of modern orangutans.^[5]

Species[]

Lufengpithecus lufengensis[]

Lufengpithecus lufengensis is an extinct ape recovered from lignite (soft coal) beds at the Shihuiba Locality in Lufeng County, Yunnan, China, dating to the latest Miocene. It was originally thought to represent two distinct species, Sivapithecus yunnanensis, thought to be an ancestor of Pongo (orangutans), and Ramapithecus lufengensis, thought to be an early human ancestor. The recognition in the 1980s that "Ramapithecus" fossils were females of Sivapithecus led to the creation of the new genus and species Lufengpithecus lufengensis to accommodate the large collection of hominoid fossils recovered at Lufeng in the 1970s. The species was recognized to have a very large degree of sexual dimorphism, more comparable to that seen in cercopithecoid monkeys than in any living ape.^[1] The fossil remains from Shihuiba included a number of relatively complete but badly crushed crania of both male and female specimens.

A series of excavations were done between 1975 and 1983 which recovered five skulls, tens of mandibles, hundreds of isolated teeth and some post-cranial bones of the species.^[6]

Lufengpithecus hudienensis[]

Lufengpithecus hudienensis was excavated in the 1980s and 1990s from a number of localities in Yuanmou County, Yunnan, China. The specimens include a large number of teeth, mandibular and maxillary fragments and the facial skeleton of a juvenile.^[7] The skull is quite distinct from that of L. lufengensis, suggesting high rates of endemism in this time and region.^[8]

Lufengpithecus keiyuanensis[]

Ape fossils collected in the 1950s at Keiyuan County in Yunnan originally attributed to Dryopithecus keiyuanensis were subsequently assigned to Lufengpithecus keiyuanensis.^[9][10]

Anatomy[]

Using an equation derived by Conroy (1987) based on the mesiodistal length of preserved teeth found, it is estimated that Lufengpithecus had a body mass between 55.4 and 67.6 kg (122 and 149 lb).^[6]

Lufengpithecus possess prominent and rounded brow (supraorbital) ridges; in females the supraorbital ridges are predicted to be squarer. The brow ridges do not form a single bar. The midsagittal line of the face is also concave.^[11] The mandibular symphysis has a moderate superior transverse torus and prominent robust inferior torus. The orbits are approximately square in outline and the interorbital contains a wide region. The maximum height of the nasal opening is at the same level as the lower margins of the eye sockets.^[12]

Dentition[]

Postcanine records show that Lufengpithecus was more dimorphic than all modern ape species. Due to the extremely high molar dimorphism, there is no overlap between male and female molar size. With respect to postcanines, Lufengpithecus has expanded the known range of sexual dimorphism.^[13] The molars have thick enamel, peripheralized cusp apices with expansive basin and a dense, complex pattern of occlusal crenulations. The pattern of compactness of the small transverse ridges in the enamel of permanent teeth of L. lufengensis are very similar to that of modern humans.^[11] The first upper incisors are high-crowned and proportionally thick (labiolingual length) compared to their breadth (mesiodistal length), with a distinct, high relief median lingual pillar. In contrast, the lower incisors are high crowned and relatively narrow mesiodistal and moderately procumbent. Male lower canines taper sharply toward the apex, and are relatively very high-crowned.^[12]

The age of molars in the assumed-female specimen PA868 was estimated 3.2-3.3 years, crown formation taking about 0.25-0.75 years, cspal enamel formation 0.4–1 years, and lateral enamel 686–1078 days. This is consistent with the growth rate of non-human great apes. She may have had gum disease.^[14]

Diet[]

Lufengpithecus probably had a diet that consisted of both hard and soft fruits. It similarly developed molar shearing crests similar to other Miocene hominids such as Proconsul, Ouranopithecus, and Dendropithecus, indicating a general preference for harder fruits. Though, Lufengpithecus has smaller incisors indicating a preference for softer foods such as leaves or berries.^[6]

An alternative theory that was developed about L. lufengensis is that their diet was strictly leaves and berries. Research was done on a set of upper and lower molars and measurements of both the mesiodistal and buccolingual cusps were done and compared with other indigenous apes of the area in the time period. L. lufengensis's molars were much larger than all the other hominoids in size. The ratio of M1 to M3 shows a pattern and when there is a high M1 to M3 ratio it indicates a consumption of more fruits rather than leaves and berries. L. lufengensis's ratio was much lower than compared to the ratio of L. hudienensis. Due to the shearing crest size of the teeth that belongs to L. lufengensis researchers believe that the species' diet consisted primarily of leaves and berries. Because the enamel on the cusp of the molars is still relatively thick, this displays they were not worn down by tough foods. The crowns on their teeth tend to be less worn than those L. hudienensis.^[15]

Paleoecology[]

Before Lufengpithecus evolved, the vegetation in the area was dominated by subtropical evergreen broad-leaved taxa with a few temperate deciduous taxa. During its time, the landscape changed and evergreen broad-leaved forests and grasses began to take over. The dominant species at the times were Quercus and Alnus. The vegetation was mostly angiosperms, followed by gymnosperms, and low-lying pteridophytes. Conifers began to decrease in this time, indicating a gradual warming of the climate. The greater diversity and warm humid climate during the late Miocene would have favored this ape's survival. Lake or wetland environments were also common, and it is postulated that Lufengpithecus lived in forests adjacent to open areas with grasses, which began expanding along with other C4 plants.^[16]

Other animals include elephants, the beaver , the rodent , the flying squirrel , and the rabbit . Animals found near the fossil include tapirs, insectivores, flying squirrels, bamboo rats, freshwater birds, fish, frogs, turtles, crocodiles, beavers, otters and terrestrial birds, all which point to a swampy or lacustrine environment.^[16]

See also[]

• Griphopithecus
• ZT 299 (Lufengpithecus)

References[]

• sciencedaily.com