Lufengpithecus lufengensis
Lufengpithecus lufengensis is a prehistoric species of hominoid from the Late Miocene found in China, named after the Lufeng site and dated around 6.2 Ma. It is the latest Miocene fossil ape that has been discovered in the entire world. Some researchers believe that genus "Lufengpithecus" could be an ancestor to African apes and hominids. Taxonomy. There are three known species of "Lufengpithecus:" "keiyuanensis" from near Kaiyuan in the Xiaolongtan Basin (10-11mya), "hudienensis" from Yuanmou Basin (7.1-8.2mya), and "lufengensis" from Shihuiba in the Lufeng Basin (6.2-6.9mya). Some argue that this taxa is a distinct clade  of late Miocene East Asian hominoids that are not closely related to any extant taxa. In fact, compared to YV0999 (a cranium of "L. hudienensis" from Yuanmou), there may have been a high degree of local endemism of apes during this time, due to the wide differences between the two species. This fits with the topographic data of Southwest China at the time, which was subject to uplift and erosion, which created the complex topography of mountain ranges and basins that is still present in current day. Discovery. In the Lufeng region of China, a Miocene hominoid site, a series  of excavations were untaken between 1975 and 1983 which recovered five skulls, tens of mandibles, hundreds of isolated teeth and some post-cranial bones of the species. Specimens include: Morphology. Anatomy. Using an equation derived by Conroy (1987) based on the mesiodistal length of preserved teeth found, it is estimated that the species within the genus "Lufengpithecus" had a body mass between 55.4 and 67.6 kg. Analysis from an excavated skull shows that male "L. lufengensis" possess supraorbital ridges which are ovoid and the transverse diameter is slightly longer than the vertical diameter; in females the supraorbital ridges are predicted  to be quadrangularly shaped rather than ovoid. The glabellar region which is located between the eyebrows and above the nose along with the frontal triangle are both very depressed. The midsagittal line of the face is also concave. Dentition. Postcanine records show that "L. lufengensis" was more dimorphic than modern ape species such as the orangutan. Therefore, at least dentally, there were large variations between males and females of the species. Researchers are unsure if "L. lufengensis" is the more dimorphic of extinct ape species, but is more dimorphic than all extant ape species. Due to the extremely high molar  dimorphism found in "L. lufengensis", there is no overlap between males and females in bivariate plots of mesiodistal and buccolingual dimensions. With respect to postcanines, "L. lufengensis" has expanded the known range of intraspecific sexual dimorphism. Dental Records also show that the "L. lufengensis" has molars with 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. The "L. lufengensis" upper central incisors are high-crowned and labiolingually  thick in relation to 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 "L. lufengensis"' lower-canines taper sharply toward the apex, appearing very glacial and are relatively very high-crowned. 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 glabella appear to be broad and depressed. There is a superior margin of nasal aperture higher than inferior margin of orbits. The nasoalveolar  clivus is also relatively short. Relation To Other Species. Fossils from the genus "Lufengpithecus" from the late Miocene is crucial in understanding hominoid evolution in Asia. The fossil being studied may be a member of the Homininae and a study wants to show an estimated age of molars in "Lufengpithecus lufengensis" at time of death. The results of the paper will help understand “Life History” in Miocene and Plio-Pleistocene hominids and great apes and humans. The author uses fossil PA868 as baseline and the fossil is thought to be a juvenile. They use the right mandibular of the fossil  which has right four premolar and permanent first molar (M1)and also has five right permanent tooth crown germs which are I1, I2, C, P3, and P4 and the author concludes that PA868 was most likely a female. Age at time of death of PA868 was estimated using the number of perikymata on the surface of the cusp to the developing cervix. Age was 2.4-4.5 years based on the central incisor germ and 2.5-4.7 years based on the canine germ. The author discovers that first molar emergence was younger than the age of death due to the emergence of  symptoms resembling gingivitis. The age of molars in the PA868 was estimated 3.2-3.3 years. The age of the crown formation took about 0.25-0.75 years for PA868. Cuspal enamel formed within 0.4–1 years. Lateral enamel formed in 686–1078 days. The age of first molar emergence for PA868 resembles that of extant great apes and is less in relation to modern humans. "Lufengpithecus lufengensis" is more similar to great apes and the hominoids and less related to monkeys and modern humans. In the juvenile mandible of "Lufengpithecus", the superior part of the anterior surface and the vertical implantation of the  anterior teeth are a lot like the adults of the same species. Additionally, the juvenile and the adult species have these features in common with early "Homo" species and early great apes. The superior transverse torus is more prominent and developed in the adult species whereas the juvenile (PA869) has a less developed superior transverse torus. In the juvenile and the adult species the lateral prominences are separated into two branches which are only similar in a single orangutan species (based on the species discussed in the paper) and not related to humans. In the juvenile there are double mental  foramina on the corpora whereas the adult species and every other species mentioned in the paper have single mental foramina. Results indicates that the corpus of juvenile mandible of "Lufengpithecus" possessed the basic structural framework of the adult mandible of same species and other species such as "Sivapithecus, Australopithecus", early "Homo", but possess a different framework from modern humans. Habitat and Range. Before the hominoid lived, the vegetation in the area was dominated by subtropical evergreen broad-leaved taxa with a few temperate deciduous taxa. During the hominoid's 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 pteridophytes. Conifers began to decrease in this time, indicating a gradual warming of the climate during this time. 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 during this time, and it is postulated that the ape lived in forests adjacent to open areas with grasses, which began expanding along with other C4 plants. These would have supplemented the diet of  this ape. Other taxa found in this time would have been "Sinocastor, Kowalskia, Pliopetaurista, Alilepus", and several proboscideans. 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. Diet. "L. lufengensis" had a diet that consisted of both hard and soft fruits based on the paleoenvironment. "L. lefungensis" had similarly developed molar shearing crests to other Miocene hominids such as "Proconsul nyanzae, Ouranopithecus macedoniensis," "Dendropithecus macinnesis" and a Yuanmou hominoid, indicating a possible preference for harder fruits. However , the Yuanmou hominoid differs from teeth of the genus "Lufengpithecus" in several aspects of the evidence studied such as tooth size proportions, M2 shearing crest development, tooth enamel thickness and body weight. When compared to hominoid species of similar regions such as a Yuanmou hominid, "L. lufengensis" has smaller front teeth indicating at least a partly more folivorous diet compared to other extinct hominoids. This means along with consuming some hard fruits, they would also consume berries and leaves. 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 L. Lufengensis's consisted primarily of leaves and berries. Upon further inspection of the upper and lower molars researchers notice a pattern on the teeth that belong to L. Lufengensis. 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 of other extinct apes that once inhabited the same area, such as L. Hudienensis. These four categories that researchers took in to account when examining the molars  supports the hypothesis that they have proposed about L. Lufengensis's diet.