Tarsiers are haplorrhine primates of the family Tarsiidae, which is itself the lone extant family within the infraorder Tarsiiformes. Although the group was once more widespread, all of its species living today are found in the islands of Southeast Asia, specifically the Philippines, Malaysia, Indonesia, and Brunei.
Strepsirrhini or Strepsirhini is a suborder of primates that includes the lemuriform primates, which consist of the lemurs of Madagascar, galagos ("bushbabies") and pottos from Africa, and the lorises from India and southeast Asia. Collectively they are referred to as strepsirrhines. Also belonging to the suborder are the extinct adapiform primates which thrived during the Eocene in Europe, North America, and Asia, but disappeared from most of the Northern Hemisphere as the climate cooled. Adapiforms are sometimes referred to as being "lemur-like", although the diversity of both lemurs and adapiforms does not support this comparison.
Brachiation, or arm swinging, is a form of arboreal locomotion in which primates swing from tree limb to tree limb using only their arms. During brachiation, the body is alternately supported under each forelimb. This form of locomotion is the primary means of locomotion for the small gibbons and siamangs of southeast Asia. Gibbons in particular use brachiation for as much as 80% of their locomotor activities. Some New World monkeys, such as spider monkeys and muriquis, were initially classified as semibrachiators and move through the trees with a combination of leaping and brachiation. Some New World species also practice suspensory behaviors by using their prehensile tail, which acts as a fifth grasping hand. Evidence has shown that the extinct ape Proconsul from the Milocene of East Africa developed an early form of suspensory behaviour, and was therefore referred to as a probrachiator.
A forelimb or front limb is one of the paired articulated appendages (limbs) attached on the cranial (anterior) end of a terrestrial tetrapod vertebrate's torso. With reference to quadrupeds, the term foreleg or front leg is often used instead. In bipedal animals with an upright posture, the term upper limb is often used.
Horsfield's tarsier, also known as the western tarsier, is the only species of tarsier in the genus Cephalopachus. It occurs on Borneo, Sumatra and nearby islands and is, like other members of the group, entirely nocturnal.
Knuckle-walking is a form of quadrupedal walking in which the forelimbs hold the fingers in a partially flexed posture that allows body weight to press down on the ground through the knuckles. Gorillas and chimpanzees use this style of locomotion, as do anteaters and platypuses.
Orthograde is a term derived from Greek ὀρθός, orthos + Latin gradi that describes a manner of walking which is upright, with the independent motion of limbs. Both New and Old World monkeys are primarily arboreal, and they have a tendency to walk with their limbs swinging in parallel to one another. This differs from the manner of walking demonstrated by the apes.
A cursorial organism is one that is adapted specifically to run. An animal can be considered cursorial if it has the ability to run fast or if it can keep a constant speed for a long distance. "Cursorial" is often used to categorize a certain locomotor mode, which is helpful for biologists who examine behaviors of different animals and the way they move in their environment. Cursorial adaptations can be identified by morphological characteristics, physiological characteristics, maximum speed, and how often running is used in life. There is much debate over how to define a cursorial animal specifically. The most accepted definitions include that a cursorial organism could be considered adapted to long-distance running at high speeds or has the ability to accelerate quickly over short distances. Among vertebrates, animals under 1 kg of mass are rarely considered cursorial, and cursorial behaviors and morphology is thought to only occur at relatively large body masses in mammals. There are a few mammals that have been termed "micro-cursors" that are less than 1 kg in mass and have the ability to run faster than other small animals of similar sizes.
Akidolestes is an extinct genus of mammals from the family spalacotheriid.
Lagerpeton is a genus of lagerpetid avemetatarsalian, comprising a single species, L. chanarensis. First described from the Chañares Formation of Argentina by A. S. Romer in 1971, Lagerpeton's anatomy is somewhat incompletely known, with fossil specimens accounting for the pelvic girdle, hindlimbs, posterior presacral, sacral and anterior caudal vertebrae. Skull and shoulder material has also been described.
A facultative biped is an animal that is capable of walking or running on two legs (bipedal), as a response to exceptional circumstances (facultative), while normally walking or running on four limbs or more. In contrast, obligate bipedalism is where walking or running on two legs is the primary method of locomotion. Facultative bipedalism has been observed in several families of lizards and multiple species of primates, including sifakas, capuchin monkeys, baboons, gibbons, gorillas, bonobos and chimpanzees. Different facultatively bipedal species employ different types of bipedalism corresponding to the varying reasons they have for engaging in facultative bipedalism. In primates, bipedalism is often associated with food gathering and transport. In lizards, it has been debated whether bipedal locomotion is an advantage for speed and energy conservation or whether it is governed solely by the mechanics of the acceleration and lizard's center of mass. Facultative bipedalism is often divided into high-speed (lizards) and low-speed (gibbons), but some species cannot be easily categorized into one of these two. Facultative bipedalism has also been observed in cockroaches and some desert rodents.
Necrolemur is a small bodied omomyid with body mass estimations ranging from 114 grams to 346 grams. Necrolemur’s teeth feature broad basins and blunt cusps, suggesting their diet consisted of mostly soft fruit, though examination of microwear patterns suggests that populations from lower latitudes also consumed insects and gums. While they do not sport a true tooth comb like modern lemurs, microwear patterns on their lower incisors suggest they engaged in fur grooming behaviors. Like tarsiers, Necrolemur had large, front-facing, close set eyes and were likely nocturnal. Analysis of cranial and postcranial fossils by paleontologists suggest members of the family Omomyidae, including the genus Necrolemur, possessed highly specialized adaptations for leaping.
Shoshonius is an extinct genus of omomyid primate that lived during the Eocene. Specimens identified as Shoshonius have been found exclusively in central Wyoming and the genus currently includes two species, Shoshonius cooperi, described by Granger in 1910, and Shoshonius bowni, described by Honey in 1990.
Arboreal locomotion is the locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some animals may scale trees only occasionally, but others are exclusively arboreal. The habitats pose numerous mechanical challenges to animals moving through them and lead to a variety of anatomical, behavioral and ecological consequences as well as variations throughout different species. Furthermore, many of these same principles may be applied to climbing without trees, such as on rock piles or mountains.
The evolution of human bipedalism, which began in primates about four million years ago, or as early as seven million years ago with Sahelanthropus, or about 12 million years ago with Danuvius guggenmosi, has led to morphological alterations to the human skeleton including changes to the arrangement and size of the bones of the foot, hip size and shape, knee size, leg length, and the shape and orientation of the vertebral column. The evolutionary factors that produced these changes have been the subject of several theories.
Suspensory behaviour is a form of arboreal locomotion or a feeding behavior that involves hanging or suspension of the body below or among tree branches. This behavior enables faster travel while reducing path lengths to cover more ground when travelling, searching for food and avoiding predators. Different types of suspensory behaviour include brachiation, climbing, and bridging. These mechanisms allow larger species to distribute their weight among smaller branches rather than balancing above these weak supports. Primates and sloths are most commonly seen using these behaviours, however, other animals such as bats may be seen hanging below surfaces to obtain food or when resting.
Adapis is an extinct adapiform primate from the Eocene of Europe. While this genus has traditionally contained five species, recent research has recognized at least six morphotypes that may represent distinct species. Adapis holds the title of the first Eocene primate ever discovered. In 1821, Georges Cuvier, who is considered to be the founding father of paleontology, discovered Adapis in fissure fillings outside of Paris, France. Given it's timing and appearance in the fossil record, Cuvier did not recognize the primate affinities of Adapis and first described it as a small extinct pachyderm; only later in the 19th century was Adapis identified as a primate.
Afrotarsius is a primate found in the Paleogene of Africa.
Archicebus is a genus of fossil primates that lived in the early Eocene forests of what is now Jingzhou in the Hubei Province in central China, discovered in 2003. The only known species, A. achilles, was a small primate, estimated to weigh approximately 20–30 grams (0.71–1.06 oz), and is the only known member of the family Archicebidae. When discovered, it was the oldest fossil haplorhine primate skeleton found, appearing to be most closely related to tarsiers and the fossil omomyids, although A. achilles is suggested to have been diurnal whereas tarsiers are nocturnal. Resembling tarsiers and simians, it was a haplorhine primate, and it also may have resembled the last common ancestor of all haplorhines as well as the last common ancestor of all primates. Its discovery further supports the hypothesis that primates originated in Asia, not in Africa.
Danuvius guggenmosi is an extinct species of great ape that lived 11.6 million years ago during the Middle–Late Miocene in southern Germany. It is the sole member of the genus Danuvius. The area at this time was probably a woodland with a seasonal climate. A male specimen was estimated to have weighed about 31 kg (68 lb), and two females 17 and 19 kg. Both genus and species were described in November 2019.
