''Afropithecus'' is a genus of

Miocene The Miocene ( ) is the first epoch (geology), 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 mea ...

hominoid with the sole species ''Afropithecus turkanensis'', it was excavated from a small site near Lake Turkana called Kalodirr in northern

Kenya Kenya, officially the Republic of Kenya, is a country located in East Africa. With an estimated population of more than 52.4 million as of mid-2024, Kenya is the 27th-most-populous country in the world and the 7th most populous in Africa. ...

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. 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 Chronological dating, date materials such as Rock (geology), rocks or carbon, in which trace radioactive impurity, impurities were selectively incorporat ...

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

University of Utah The University of Utah (the U, U of U, or simply Utah) is a public university, public research university in Salt Lake City, Utah, United States. It was established in 1850 as the University of Deseret (Book of Mormon), Deseret by the General A ...

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

cranial Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek language, Greek roots, describe something in its standard anatomical position. Thi ...

mandible In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla). The jawbone i ...

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-physiology ...

and post-cranial remains. The

type specimen In biology, a type is a particular wikt:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally associated. In other words, a type is an example that serves to ancho ...

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'', 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 most animals. There are several types of skeletons, including the exoskeleton, which is a rigid outer shell that holds up an organism's shape; the endoskeleton, a rigid internal fram ...

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

quadruped Quadrupedalism is a form of locomotion in which animals have four legs that are used to bear weight and move around. An animal or machine that usually maintains a four-legged posture and moves using all four legs is said to be a quadruped (fr ...

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 (anatomy), rostrum, beak or proboscis. The wet furless surface around the nostrils of the n ...

, the facial skeleton, frontal, much of the coronal structure, most of the sphenoid, and relatively unworn adult dentition; the right orbit (virtually complete), the right zygomatic, the pterygoid, most of the sphenoid and lesser wings, the

maxilla In vertebrates, the maxilla (: maxillae ) 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 two maxil ...

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 mammals h ...

, 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, wher ...

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 between its very procumbent second incisor (KNM-WT 16999 had large, broad incisors) and the canine. 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 (: metatarsi) are a group of five long bones in the midfoot, located between the tarsal bones (which form the heel and the ankle) and the phalanges ( toes). Lacking individual names, the metatarsal bones are ...

, 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 or ulnar bone (: ulnae or ulnas) is a long bone in the forearm stretching from the elbow to the wrist. It is on the same side of the forearm as the little finger, running parallel to the Radius (bone), radius, the forearm's other long ...

, 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, in contrast to that of '' Morotopithecus''.

References

External links