A primate is a eutherian mammal constituting the taxonomic order Primates. Primates arose 85–55 million years ago from small terrestrial mammals, which adapted to living in the trees of tropical forests: many primate characteristics represent adaptations to life in this challenging environment, including large brains, visual acuity, color vision, altered shoulder girdle, dexterous hands. Primates range in size from Madame Berthe's mouse lemur, which weighs 30 g, to the eastern gorilla, weighing over 200 kg. There are 190 -- 448 species of living primates, depending on. New primate species continue to be discovered: over 25 species were described in the first decade of the 2000s, eleven since 2010. Primates are divided into two distinct suborders; the first is the strepsirrhines - lemurs and lorisids. The second is haplorhines - the "dry-nosed" primates - tarsier and ape clades, the last of these including humans. Simians are monkeys and apes, cladistically including: the catarrhines consisting of the Old World monkeys and apes.
Forty million years ago, simians from Africa migrated to South America by drifting on debris, gave rise to the New World monkeys. Twenty five million years ago the remaining Old World simians split into Old World monkeys. Common names for the simians are the baboons, macaques and great apes. Primates have large brains compared to other mammals, as well as an increased reliance on visual acuity at the expense of the sense of smell, the dominant sensory system in most mammals; these features are more developed in monkeys and apes, noticeably less so in lorises and lemurs. Some primates are trichromats, with three independent channels for conveying color information. Except for apes, primates have tails. Most primates have opposable thumbs. Many species are sexually dimorphic. Primates have slower rates of development than other sized mammals, reach maturity and have longer lifespans. Depending on the species, adults may live in solitude, in mated pairs, or in groups of up to hundreds of members; some primates, including gorillas and baboons, are terrestrial rather than arboreal, but all species have adaptations for climbing trees.
Arboreal locomotion techniques used include leaping from tree to tree and swinging between branches of trees. Primates are among the most social of animals, forming pairs or family groups, uni-male harems, multi-male/multi-female groups. Non-human primates have at four types of social systems, many defined by the amount of movement by adolescent females between groups. Most primate species remain at least arboreal: the exceptions are some great apes and humans, who left the trees for the ground and now inhabit every continent. Close interactions between humans and non-human primates can create opportunities for the transmission of zoonotic diseases virus diseases, including herpes, ebola and hepatitis. Thousands of non-human primates are used in research around the world because of their psychological and physiological similarity to humans. About 60% of primate species are threatened with extinction. Common threats include deforestation, forest fragmentation, monkey drives, primate hunting for use in medicines, as pets, for food.
Large-scale tropical forest clearing for agriculture most threatens primates. The English name "primates" is derived from Old French or French primat, from a noun use of Latin primat-, from primus; the name was given by Carl Linnaeus. The relationships among the different groups of primates were not understood until recently, so the used terms are somewhat confused. For example, "ape" has been used either as an alternative for "monkey" or for any tailless human-like primate. Sir Wilfrid Le Gros Clark was one of the primatologists who developed the idea of trends in primate evolution and the methodology of arranging the living members of an order into an "ascending series" leading to humans. Used names for groups of primates such as "prosimians", "monkeys", "lesser apes", "great apes" reflect this methodology. According to our current understanding of the evolutionary history of the primates, several of these groups are paraphyletic: a paraphyletic group is one which does not include all the descendants of the group's common ancestor.
In contrast with Clark's methodology, modern classifications identify only those groupings that are monophyletic. The cladogram below shows one possible classification sequence of the living primates: groups that use common names are shown on the right. All groups with scientific names are monophyletic, the sequence of scientific classification reflects the evolution
Sahelanthropus tchadensis is an extinct species of the Hominini and is the ancestor to Orrorin, dated to about 7 million years ago, during the Miocene epoch very close to the time of the chimpanzee–human divergence. Few specimens other than the partial skull, nicknamed Toumaï, are known. Existing fossils include a small cranium named Toumaï, five pieces of jaw, some teeth, making up a head that has a mixture of derived and primitive features; the braincase, being only 320 cm3 to 380 cm3 in volume, is similar to that of extant chimpanzees and is notably less than the approximate human volume of 1350 cm3. The teeth, brow ridges, facial structure differ markedly from those found in Homo sapiens. Cranial features show a flatter face, u-shaped dental arcade, small canines, an anterior foramen magnum, heavy brow ridges. No postcranial remains have been recovered; the only known skull suffered a large amount of distortion during the time of fossilisation and discovery, as the cranium is dorsoventrally flattened, the right side is depressed.
Sahelanthropus tchadensis may have walked on two legs. However, because no postcranial remains have been discovered, it is not known definitively whether Sahelanthropus was indeed bipedal, although claims for an anteriorly placed foramen magnum suggests that this may have been the case. Upon examination of the foramen magnum in the primary study, the lead author speculated that a bipedal gait "would not be unreasonable" based on basicranial morphology similar to more recent hominins; some palaeontologists have disputed this interpretation, stating that the basicranium, as well as dentition and facial features, do not represent adaptations unique to the hominin clade, nor indicative of bipedalism. Further, according to recent information, what might be a femur of a hominid was discovered near the cranium—but which has not been published nor accounted for. Fifteen years after the discovery of the fossil, the anthropologist Roberto Macchiarelli—professor at the University of Poitiers and the Museum of Natural History of Paris—suspects Michel Brunet and his laboratory in Poitiers of blocking information about a femur found close to the skull.
That the laboratory would have delayed identification may question the bipedalism of Toumaï. The fossils were discovered in the Djurab Desert of Chad by a team of four led by a Frenchman, Alain Beauvilain, three Chadians, Adoum Mahamat, Djimdoumalbaye Ahounta, Gongdibé Fanoné, members of the Mission paleoanthropologique Franco-tchadienne led by Michel Brunet. All known material of Sahelanthropus was found between July 2001 and March 2002 at three sites: TM 247, TM 266, which yielded most of the material, including a cranium and a femur, TM 292; the discoverers claimed that S. tchadensis is the oldest-known human ancestor after the split of the human line from that of chimpanzees. The bones were found far from most previous hominin fossil finds, which are from Eastern and Southern Africa. However, an Australopithecus bahrelghazali mandible was found in Chad by Mamelbaye Tomalta and Alain Beauvilain, Michel Brunet and Aladji H. E. Moutaye as early as 1995. With the sexual dimorphism known to have existed in early hominins, the difference between Ardipithecus and Sahelanthropus may not be large enough to warrant a separate species for the latter.
Sahelanthropus may represent a common ancestor of humans and chimpanzees, though no consensus has been reached yet by the scientific community. The original placement of this species as a human ancestor but not a chimpanzee ancestor would complicate the picture of human phylogeny. In particular, if Toumaï is indeed a direct human ancestor its facial features bring into doubt the status of Australopithecus whose thickened brow ridges were reported to be similar to those of some fossil hominins, where the brow ridge morphology of Sahelanthropus differs from that observed in all australopithecines, most fossil hominins and extant humans. Another possibility is that Toumaï is related to both humans and chimpanzees, but is the ancestor of neither. Brigitte Senut and Martin Pickford, the discoverers of Orrorin tugenensis, suggested that the features of S. tchadensis are consistent with a female proto-gorilla. If this claim is upheld the find would lose none of its significance, because at present few chimpanzee or gorilla ancestors have been found anywhere in Africa.
Thus if S. tchadensis is an ancestral relative of the chimpanzees or gorillas it represents the earliest known member of their lineage. And S. tchadensis does indicate that the last common ancestor of humans and chimpanzees is unlikely to resemble extant chimpanzees, as had been supposed by some paleontologists. A further possibility, highlighted by research published in 2012, is that the human–chimpanzee split is earlier than thought, with a possible range of 7 to 13 million years ago, based on slower than thought changes between generations in human DNA. Indeed, some researchers consider suggestions that Sahelanthropus is too early to be a human ancestor to have evaporated. Sediment isotope analysis of cosmogenic atoms in the fossil yielded an age of about 7 million years. In this case, the fossils were found exposed in loose sand. In fact, Toumaï may have been reburied in the r
Human evolution is the evolutionary process that led to the emergence of anatomically modern humans, beginning with the evolutionary history of primates—in particular genus Homo—and leading to the emergence of Homo sapiens as a distinct species of the hominid family, the great apes. This process involved the gradual development of traits such as human bipedalism and language, as well as interbreeding with other hominins, which indicate that human evolution was not linear but a web; the study of human evolution involves several scientific disciplines, including physical anthropology, archaeology, neurobiology, linguistics, evolutionary psychology and genetics. Genetic studies show that primates diverged from other mammals about 85 million years ago, in the Late Cretaceous period, the earliest fossils appear in the Paleocene, around 55 million years ago. Within the Hominoidea superfamily, the Hominidae family diverged from the Hylobatidae family some 15–20 million years ago. Human evolution from its first separation from the last common ancestor of humans and chimpanzees is characterized by a number of morphological, developmental and behavioral changes.
The most significant of these adaptations are bipedalism, increased brain size, lengthened ontogeny, decreased sexual dimorphism. The relationship between these changes is the subject of ongoing debate. Other significant morphological changes included the evolution of a power and precision grip, a change first occurring in H. erectus. Bipedalism is the basic adaptation of the hominid and is considered the main cause behind a suite of skeletal changes shared by all bipedal hominids; the earliest hominin, of primitive bipedalism, is considered to be either Sahelanthropus or Orrorin, both of which arose some 6 to 7 million years ago. The non-bipedal knuckle-walkers, the gorilla and chimpanzee, diverged from the hominin line over a period covering the same time, so either of Sahelanthropus or Orrorin may be our last shared ancestor. Ardipithecus, a full biped, arose 5.6 million years ago. The early bipeds evolved into the australopithecines and still into the genus Homo. There are several theories of the adaptation value of bipedalism.
It is possible that bipedalism was favored because it freed the hands for reaching and carrying food, saved energy during locomotion, enabled long distance running and hunting, provided an enhanced field of vision, helped avoid hyperthermia by reducing the surface area exposed to direct sun. A new study provides support for the hypothesis that walking on two legs, or bipedalism, evolved because it used less energy than quadrupedal knuckle-walking. However, recent studies suggest that bipedality without the ability to use fire would not have allowed global dispersal; this change in gait saw a lengthening of the legs proportionately when compared to the length of the arms, which were shortened through the removal of the need for brachiation. Another change is the shape of the big toe. Recent studies suggest that Australopithecines still lived part of the time in trees as a result of maintaining a grasping big toe; this was progressively lost in Habilines. Anatomically, the evolution of bipedalism has been accompanied by a large number of skeletal changes, not just to the legs and pelvis, but to the vertebral column and ankles, skull.
The femur evolved into a more angular position to move the center of gravity toward the geometric center of the body. The knee and ankle joints became robust to better support increased weight. To support the increased weight on each vertebra in the upright position, the human vertebral column became S-shaped and the lumbar vertebrae became shorter and wider. In the feet the big toe moved into alignment with the other toes to help in forward locomotion; the arms and forearms shortened relative to the legs making it easier to run. The foramen magnum migrated under more anterior; the most significant changes occurred in the pelvic region, where the long downward facing iliac blade was shortened and widened as a requirement for keeping the center of gravity stable while walking. A drawback is that the birth canal of bipedal apes is smaller than in knuckle-walking apes, though there has been a widening of it in comparison to that of australopithecine and modern humans, permitting the passage of newborns due to the increase in cranial size but this is limited to the upper portion, since further increase can hinder normal bipedal movement.
The shortening of the pelvis and smaller birth canal evolved as a requirement for bipedalism and had significant effects on the process of human birth, much more difficult in modern humans than in other primates. During human birth, because of the variation in size of the pelvic region, the fetal head must be in a transverse position during entry into the birth canal and rotate about 90 degrees upon exit; the smaller birth canal became a limiting factor to brain size increases in early humans and prompted a shorter gestation period leading to the relative immaturity of human
The human eye is an organ which reacts to light and pressure. As a sense organ, the mammalian eye allows vision. Human eyes help to provide a three dimensional, moving image coloured in daylight. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth; the human eye can differentiate between about 10 million colors and is capable of detecting a single photon. Similar to the eyes of other mammals, the human eye's non-image-forming photosensitive ganglion cells in the retina receive light signals which affect adjustment of the size of the pupil and suppression of the hormone melatonin and entrainment of the body clock; the eye is not shaped like a perfect sphere, rather it is a fused two-piece unit, composed of the anterior segment and the posterior segment. The anterior segment is made up of the cornea and lens; the cornea is transparent and more curved, is linked to the larger posterior segment, composed of the vitreous, retina and the outer white shell called the sclera.
The cornea is about 11.5 mm in diameter, 1/2 mm in thickness near its center. The posterior chamber constitutes the remaining five-sixths; the cornea and sclera are connected by an area termed the limbus. The iris is the pigmented circular structure concentrically surrounding the center of the eye, the pupil, which appears to be black; the size of the pupil, which controls the amount of light entering the eye, is adjusted by the iris' dilator and sphincter muscles. Light energy enters the eye through the cornea, through the pupil and through the lens; the lens shape is controlled by the ciliary muscle. Photons of light falling on the light-sensitive cells of the retina are converted into electrical signals that are transmitted to the brain by the optic nerve and interpreted as sight and vision. Dimensions differ among adults by only one or two millimetres, remarkably consistent across different ethnicities; the vertical measure less than the horizontal, is about 24 mm. The transverse size of a human adult eye is 24.2 mm and the sagittal size is 23.7 mm with no significant difference between sexes and age groups.
Strong correlation has been found between the width of the orbit. The typical adult eye has an anterior to posterior diameter of 24 millimetres, a volume of six cubic centimetres, a mass of 7.5 grams.. The eyeball grows increasing from about 16–17 millimetres at birth to 22.5–23 mm by three years of age. By age 12, the eye attains its full size; the eye is made up of layers, enclosing various anatomical structures. The outermost layer, known as the fibrous tunic, is composed of the sclera; the middle layer, known as the vascular tunic or uvea, consists of the choroid, ciliary body, pigmented epithelium and iris. The innermost is the retina, which gets its oxygenation from the blood vessels of the choroid as well as the retinal vessels; the spaces of the eye are filled with the aqueous humour anteriorly, between the cornea and lens, the vitreous body, a jelly-like substance, behind the lens, filling the entire posterior cavity. The aqueous humour is a clear watery fluid, contained in two areas: the anterior chamber between the cornea and the iris, the posterior chamber between the iris and the lens.
The lens is suspended to the ciliary body by the suspensory ligament, made up of hundreds of fine transparent fibers which transmit muscular forces to change the shape of the lens for accommodation. The vitreous body is a clear substance composed of water and proteins, which give it a jelly-like and sticky composition; the approximate field of view of an individual human eye varies by facial anatomy, but is 30° superior, 45° nasal, 70° inferior, 100° temporal. For both eyes combined visual field is 200 ° horizontal, it is 13700 square degrees for binocular vision. When viewed at large angles from the side, the iris and pupil may still be visible by the viewer, indicating the person has peripheral vision possible at that angle. About 15° temporal and 1.5° below the horizontal is the blind spot created by the optic nerve nasally, 7.5° high and 5.5° wide. The retina has a static contrast ratio of around 100:1; as soon as the eye moves to acquire a target, it re-adjusts its exposure by adjusting the iris, which adjusts the size of the pupil.
Initial dark adaptation takes place in four seconds of profound, uninterrupted darkness. The process is nonlinear and multifaceted, so an interruption by light exposure requires restarting the dark adaptation process over again. Full adaptation is dependent on good blood flow; the human eye can detect a luminance range of 1014, or one hundred trillion, from 10−6 cd/m2, or one millionth of a candela per square meter to 108 cd/m2 or one hundred million candelas per square meter. This range does not include looking at the midday lightning discharge. At the low end o
Contrast is the difference in luminance or colour that makes an object distinguishable. In visual perception of the real world, contrast is determined by the difference in the color and brightness of the object and other objects within the same field of view; the human visual system is more sensitive to contrast than absolute luminance. The maximum contrast of an image is dynamic range. According to Campbell and Robson, the human contrast sensitivity function shows a typical band-pass filter shape peaking at around 4 cycles per degree with sensitivity dropping off either side of the peak; this finding has led many to claim that the human visual system is most sensitive in detecting contrast differences occurring at 4 cycles per degree. However, the claim of frequency sensitivity is problematic given, for example, that changes of distance don't seem to affect the relevant perceptual patterns (as noted, for example, in the figure caption to Solomon and Pelli While the latter authors are referring to letters, they make no objective distinction between these and other shapes.
The relative insensitivity of contrast effects to distance may be observed by casual inspection of a paradigmantic sweep grating, as may be observed here The high-frequency cut-off represents the optical limitations of the visual system's ability to resolve detail and is about 60 cycles per degree. The high-frequency cut-off is related to the packing density of the retinal photoreceptor cells: a finer matrix can resolve finer gratings; the low frequency drop-off is due to lateral inhibition within the retinal ganglion cells. A typical retinal ganglion cell presents a centre region with either excitation or inhibition and a surround region with the opposite sign. By using coarse gratings, the bright bands fall on the inhibitory as well as the excitatory region of the ganglion cell resulting in lateral inhibition and account for the low-frequency drop-off of the human contrast sensitivity function. One experimental phenomenon is the inhibition of blue in the periphery if blue light is displayed against white, leading to a yellow surrounding.
The yellow is derived from the inhibition of blue on the surroundings by the center. Since white minus blue is red and green, this mixes to become yellow. For example, in the case of graphical computer displays, contrast depends on the properties of the picture source or file and the properties of the computer display, including its variable settings. For some screens the angle between the screen surface and the observer's line of sight is important. There are many possible definitions of contrast; some include color. Travnikova laments, "Such a multiplicity of notions of contrast is inconvenient, it complicates the solution of many applied problems and makes it difficult to compare the results published by different authors."Various definitions of contrast are used in different situations. Here, luminance contrast is used as an example, but the formulas can be applied to other physical quantities. In many cases, the definitions of contrast represent a ratio of the type Luminance difference Average luminance.
The rationale behind this is that a small difference is negligible if the average luminance is high, while the same small difference matters if the average luminance is low. Below, some common definitions are given. Weber contrast is defined as I − I b I b, with I and I b representing the luminance of the features and the background, respectively; the measure is referred to as Weber fraction, since it is the term, constant in Weber's Law. Weber contrast is used in cases where small features are present on a large uniform background, i.e. where the average luminance is equal to the background luminance. Michelson contrast is used for patterns where both bright and dark features are equivalent and take up similar fractions of the area; the Michelson contrast is defined as I m a x − I m i n I m a x + I m i n, with I m a x and I m i n representing the highest and lowest luminance. The denominator represents twice the average of minimum luminances; this form of contrast is an effective way to quantify contrast for periodic functions f and is known as the modulation mf of a periodic signal f.
Modulation quantifies the relative amount by which the amplitude /2 of f stands out from the average
The bonobo historically called the pygmy chimpanzee and less the dwarf or gracile chimpanzee, is an endangered great ape and one of the two species making up the genus Pan. Although bonobos are not a subspecies of chimpanzees, but rather a distinct species in their own right, both species are sometimes referred to collectively using the generalized term chimpanzees, or chimps. Taxonomically, the members of the chimpanzee/bonobo subtribe; the bonobo is distinguished by long legs, pink lips, dark face and tail-tuft through adulthood, parted long hair on its head. The bonobo is found in a 500,000 km2 area of the Congo Basin in the Democratic Republic of the Congo, Central Africa; the species is omnivorous and inhabits primary and secondary forests, including seasonally inundated swamp forests. Political instability in the region and the timidity of bonobos has meant there has been little field work done observing the species in its natural habitat. Along with the common chimpanzee, the bonobo is the closest extant relative to humans.
Because the two species are not proficient swimmers, the formation of the Congo River 1.5–2 million years ago led to the speciation of the bonobo. Bonobos live south of the river, thereby were separated from the ancestors of the common chimpanzee, which live north of the river. There are no concrete data on population numbers, but the estimate is between 29,500 and 50,000 individuals; the species is listed as Endangered on the IUCN Red List and is threatened by habitat destruction and human population growth and movement, though commercial poaching is the most prominent threat. They live 40 years in captivity. Despite the alternative common name "pygmy chimpanzee", the bonobo is not diminutive when compared to the common chimpanzee, with exception of its head; the appellative "pygmy" is instead owed to its namer, Ernst Schwarz, who classified the species after observing a mislabeled bonobo cranium, due to the diminutive size compared to the chimpanzee's counterpart. The name "bonobo" first appeared in 1954, when Eduard Paul Tratz and Heinz Heck proposed it as a new and separate generic term for pygmy chimpanzees.
The name is thought to be a misspelling on a shipping crate from the town of Bolobo on the Congo River near the location from which the first bonobo specimens were collected in the 1920s. Fossils of Pan species were not described until 2005. Existing chimpanzee populations in West and Central Africa do not overlap with the major human fossil sites in East Africa. However, Pan fossils have now been reported from Kenya; this would indicate that both humans and members of the Pan clade were present in the East African Rift Valley during the Middle Pleistocene. According to A. Zihlman, bonobo body proportions resemble those of Australopithecus, leading evolutionary biologist Jeremy Griffith to suggest that bonobos may be a living example of our distant human ancestors. German anatomist Ernst Schwarz is credited with being the first Westerner to recognise the bonobo as being distinctive, in 1928, based on his analysis of a skull in the Tervuren museum in Belgium, thought to have belonged to a juvenile chimpanzee.
Schwarz published his findings in 1929. In 1933, American anatomist Harold Coolidge offered a more detailed description of the bonobo, elevated it to species status; the American psychologist and primatologist Robert Yerkes was one of the first scientists to notice major differences between bonobos and chimpanzees. These were first discussed in detail in a study by Eduard Paul Tratz and Heinz Heck published in the early 1950s; the first official publication of the sequencing and assembly of the bonobo genome became publicly available in June 2012. It was deposited with the International Nucleotide Sequence Database Collaboration under the EMBL accession number AJFE01000000 after a previous analysis by the National Human Genome Research Institute confirmed that the bonobo genome is about 0.4% divergent from the chimpanzee genome. In addition, as of 2011 Svante Pääbo's group at the Max Planck Institute for Evolutionary Anthropology were sequencing the genome of a female bonobo from the Leipzig zoo.
Studies showed that chimpanzees and bonobos are more related to humans than to gorillas. In the crucial Nature paper reporting on initial genome comparisons, researchers identified 35 million single-nucleotide changes, five million insertion or deletion events, a number of chromosomal rearrangements which constituted the genetic differences between the two Pan species and humans, covering 98% of the same genes. While many of these analyses have been performed on the common chimpanzee rather than the bonobo, the differences between the two Pan species are unlikely to be substantial enough to affect the Pan-Homo comparison significantly. There still is controversy, however. Scientists such as Jared Diamond in The Third Chimpanzee, Morris Goodman of Wayne State University in Detroit suggest that the bonobo and common chimpanzee are so related to humans that their genus name should be classified with the human genus Homo: Homo paniscus, Homo sylvestris, or Homo arboreus. An alternative philosophy suggests that the term Homo sapiens is the misnomer rather, that humans should be reclassified as Pan sapiens, though this would violate the Principle of Priority, as Homo was named before Pan.
In either case, a name change of the genus would have implications on the taxonomy of extinct species related to humans, including Australopithecus. Th
Gibbon–human last common ancestor
The gibbon–human last common ancestor is the last common ancestor shared by the families Hominidae and Hylobatidae. In other words, GHLCA is ancestor of the Orangutan–human last common ancestor on one hand and gibbons on the other. Due to complex hybrid speciation, it is not possible to give a precise estimate on the age of this ancestral population, it is estimated to have lived 15.9 to 17.6 million years ago during the early Miocene. The species, which has not been identified, was smaller than thought and about the size of a gibbon; the family of Hylobatidae has four gibbon genera containing 20 different species. Each genus has a different number of chromosomes. Despite extensive genomic analysis the ordering of the genera is not clear; the extinct Bunopithecus sericus was a gibbon-like ape. Whole genome molecular dating analyses indicate that the gibbon lineage diverged from that of great apes around 16.8 million years ago. Adaptive divergence associated with chromosomal rearrangements led to rapid radiation of the four genera 5-7 Mya.
Each genus comprises a distinct, well-delineated lineage, but the sequence and timing of divergences among these genera has been hard to resolve with whole genome data, due to radiative speciations and extensive incomplete lineage sorting. The various speciations resulted in short internal branches in the species phylogeny. An analysis based on morphology suggests that the four genera are ordered as A coalescent-based species tree analysis of genome-scale datasets suggests a phylogeny for the four genera ordered as. Family Hylobatidae: gibbons Physical features are not enough to work out the relationships of the gibbon genera; the family is divided into four genera based on their diploid chromosome number: Hylobates, Hoolock and Symphalangus. There is an extinct fifth genus named Bunopithecus, either a gibbon or gibbon-like ape. An extinct sixth genus, was identified in 2018 based on a partial skull found in China. Genus Bunopithecus Bunopithecus sericus Genus Junzi Junzi imperialis Because fossils are so scarce it is not clear what GHLCA looked like.
It is unknown whether GHLCA had a broad, flat rib cage like their descendants. But it is that he was a small animal and only weighed 12 kilograms; this contradicts previous theories that they were the size of chimpanzees and that apes moved to hanging and swinging from trees in order to get off the ground because they were too big. There might have been an arms race in brachiating to reach the best food; the Hominidae which came were smaller than their ancestors, contrary to normal evolution where animals get larger over their evolutionary development. Chimpanzee–human last common ancestor Gorilla–human last common ancestor Orangutan–human last common ancestor History of hominoid taxonomy List of human evolution fossils