''Afropithecus'' is a genus of

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" ...

hominoid Apes (collectively Hominoidea ) are a clade of Old World simians native to sub-Saharan Africa and Southeast Asia (though they were more widespread in Africa, most of Asia, and as well as Europe in prehistory), which together with its sister g ...

with the sole species ''Afropithecus turkanensis'', it was excavated from a small site near

Lake Turkana Lake Turkana (), formerly known as Lake Rudolf, is a lake in the Kenyan Rift Valley, in northern Kenya, with its far northern end crossing into Ethiopia. It is the world's largest permanent desert lake and the world's largest alkaline lake ...

called Kalodirr in northern

Kenya ) , national_anthem = " Ee Mungu Nguvu Yetu"() , image_map = , map_caption = , image_map2 = , capital = Nairobi , coordinates = , largest_city = Nairobi , ...

in 1986 and named by

Richard Leakey Richard Erskine Frere Leakey (19 December 1944 – 2 January 2022) was a Kenyan paleoanthropologist, conservationist and politician. Leakey held a number of official positions in Kenya, mostly in institutions of archaeology and wildlife cons ...

and

Meave Leakey Meave G. Leakey (born Meave Epps; 28 July 1942) is a British palaeoanthropologist. She works at Stony Brook University and is co-ordinator of Plio-Pleistocene research at the Turkana Basin Institute. She studies early hominid evolution and has ...

. The estimated age of ''Afropithecus'' is between 16 and 18 million years old, which was determined with

radiometric dating Radiometric dating, radioactive dating or radioisotope dating is a technique which is used to date materials such as rocks or carbon, in which trace radioactive impurities were selectively incorporated when they were formed. The method compares t ...

techniques and the geological studies conducted by Broschetto and Brown from the

University of Utah The University of Utah (U of U, UofU, or simply The U) is a public research university in Salt Lake City, Utah. It is the flagship institution of the Utah System of Higher Education. The university was established in 1850 as the University of D ...

. In total there are 46 recovered specimens from Kalodirr relating to ''Afropithecus'' consisting of cranial,

mandible In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bon ...

dentition Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, it is the characteristic arrangement, kind, and number of teeth in a given species at a given age. That is, the number, type, and morpho-physiolog ...

and post-cranial remains. The

type specimen In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to anchor or centralizes the ...

of ''Afropithecus turkanensis'' is KNM-WK 16999.

Morphology

Richard Leakey and Meave Leakey first described ''Afropithecus turkanensis'' to be a large hominoid which appeared to have relatively thick enamel. Leakey suggested that ''A. turkanensis'' shared postcranial features with the species ''

Proconsul nyanzae ''Ekembo nyanzae'', originally classed as a species of '' Proconsul'', is a species of fossil primate first discovered by Louis Leakey on Rusinga Island in 1942, which he published in ''Nature'' in 1943. It is also known by the name ''Dryopithe ...

'', which is the best known Miocene genus with literally hundreds of fossils having been found representing almost all

skeletal A skeleton is the structural frame that supports the body of an animal. There are several types of skeletons, including the exoskeleton, which is the stable outer shell of an organism, the endoskeleton, which forms the support structure inside ...

elements, and sharing cranial features with '' Aegyptopithecus zeuxis'' and ''Heliopithecus'' which had two weathered molars that indicated a general distinction from known large early

catarrhines 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 W ...

, and later concluded that ''A. turkanenensis'' was a primitive, arboreal

quadruped Quadrupedalism is a form of locomotion where four limbs are used to bear weight and move around. An animal or machine that usually maintains a four-legged posture and moves using all four limbs is said to be a quadruped (from Latin ''quattuo ...

similar to ''P. nyanzae'', and that ''A. turkanensis'' had primitive facial morphology and derived dental characteristics that would suggest a diet of hard fruits. Leakey also synonymised ''Heliopithecus'' with ''Afropithecus''.

Cranial morphology

The type specimen, KNM-WT 16999 is composed of a long distinct

snout A snout is the protruding portion of an animal's face, consisting of its nose, mouth, and jaw. In many animals, the structure is called a muzzle, rostrum, or proboscis. The wet furless surface around the nostrils of the nose of many mammals is ...

, the facial skeleton,

frontal Front may refer to: Arts, entertainment, and media Films * ''The Front'' (1943 film), a 1943 Soviet drama film * ''The Front'', 1976 film Music *The Front (band), an American rock band signed to Columbia Records and active in the 1980s and ea ...

, much of the coronal structure, most of the sphenoid, and relatively unworn adult dentition; the right orbit (virtually complete), the right zygomatic, the

pterygoid Pterygoid, from the Greek for 'winglike', may refer to: * Pterygoid bone, a bone of the palate of many vertebrates * Pterygoid processes of the sphenoid bone ** Lateral pterygoid plate ** Medial pterygoid plate * Lateral pterygoid muscle * Med ...

, most of the sphenoid and lesser wings, the

maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The ...

and

premaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has ...

, and adult dentition with procumbent

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, w ...

s. The surface on the right side maxilla and premaxilla along with the enamel on the right molars has been lost over time and has been replaced with calcite crystals, which only provide the general shape and not the details. From dentition it is known that the palate, which is almost completely calcified, of ''A. turkanensis'' is shallow, long and narrow with tooth rows that converge posteriorly, and it is probable the tooth rows were originally nearly parallel. A. turkanensis had a 6.5mm

diastema A diastema (plural diastemata, from Greek διάστημα, space) is a space or gap between two teeth. Many species of mammals have diastemata as a normal feature, most commonly between the incisors and molars. More colloquially, the condition ...

between its very procumbent second incisor (KNM-WT 16999 had large, broad incisors) and the

canine Canine may refer to: Zoology and anatomy * a dog-like Canid animal in the subfamily Caninae ** '' Canis'', a genus including dogs, wolves, coyotes, and jackals ** Dog, the domestic dog * Canine tooth, in mammalian oral anatomy People with the ...

. The thickness of the enamel on the molars is often reported when fossils are being recorded and used to make comparisons across taxa. The thickness is referred to either as "thin" or "thick" and is commonly assessed as a linear measurement of the enamel on worn or naturally fractured teeth. From enamel testing it has been suggested that ''A. turkanensis'' is the oldest known thick-enamelled hominoid, which is what would distinguish it from '' Kenyapithecus''.

Post-cranial morphology

Post cranial remains such as KNM-WK 16901, includes an associated right fibula (lacking the proximal portion, and is approximately the same size as ''Pan troglodytes''; 184 mm), a right proximal third

metatarsal The metatarsal bones, or metatarsus, are a group of five long bones in the foot, located between the tarsal bones of the hind- and mid-foot and the phalanges of the toes. Lacking individual names, the metatarsal bones are numbered from the med ...

, a right fourth metatarsal lacking the head, and an incomplete first metatarsal head. Other post-cranial remains include: KNM-WK 17016P a large right

ulna The ulna (''pl''. ulnae or ulnas) is a long bone found in the forearm that stretches from the elbow to the smallest finger, and when in anatomical position, is found on the medial side of the forearm. That is, the ulna is on the same side of t ...

, and foot or hand bones: KNM-WK 17008, KNM-WK 18395.

Feeding

Morphological analysis of the teeth and palate of ''Afropithecus'' suggests that it utilized a sclerocarpic foraging diet similar to members of

Pitheciidae The Pitheciidae () are one of the five families of New World monkeys now recognised. Formerly, they were included in the family Atelidae. The family includes the titis, saki monkeys and uakaris. Most species are native to the Amazon region of B ...

, in contrast to that of ''

Morotopithecus ''Morotopithecus'' is a species of fossil ape discovered in Miocene-age deposits of Moroto, Uganda. The phylogenetic status of ''Morotopithecus bishopi'' is debated to the extent that it challenges established views on the connection between Mi ...

''.

References

External links