''Proconsul africanus'' was an

ape 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 siste ...

which lived from about 23 to 14 million years ago during the

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 recen ...

epoch. It was a fruit eater and its brain was larger than that of a monkey, although probably not as large as that of a modern ape. It was named by paleontologist Arthur Hopwood in 1933 after a number of chimpanzees all called Consul, which performed human like circus acts, such as riding a bicycle and playing the piano, in the late nineteenth and early twentieth centuries. Other species of the genus ''

Proconsul A proconsul was an official of ancient Rome who acted on behalf of a consul. A proconsul was typically a former consul. The term is also used in recent history for officials with delegated authority. In the Roman Republic, military command, or ' ...

'' have since been discovered.

Discovery

The Leakey expedition of 1947–1948 to

Rusinga Island Rusinga Island, with an elongated shape approximately 10 miles (16 km) from end to end and 3 miles (5 km) at its widest point, lies in the eastern part of Lake Victoria at the mouth of the Winam Gulf. Part of Kenya, it is linked to Mbita ...

Lake Victoria Lake Victoria is one of the African Great Lakes. With a surface area of approximately , Lake Victoria is Africa's largest lake by area, the world's largest tropical lake, and the world's second-largest fresh water lake by surface area after ...

uncovered more species of ''Proconsul''.

Mary Leakey Mary Douglas Leakey, FBA (née Nicol, 6 February 1913 – 9 December 1996) was a British paleoanthropologist who discovered the first fossilised ''Proconsul A proconsul was an official of ancient Rome who acted on behalf of a consul. A pro ...

made an especially complete find of ''Proconsul'' there in 1948,Leakey, M.D. 1948. "The discovery of the skull and associated mandible of a Miocene Ape." ''The Archaeological News Letter'' 8, December 1948, 3. which was for a number of decades labeled ''africanus'', but was reclassified as ''heseloni'' in 1993 by

Alan Walker Alan Olav Walker (born 24 August 1997) is a British-born Norwegian music producer and DJ primarily known for the critically acclaimed single " Faded" (2015), which was certified platinum in 14 countries. He has also made several songs including ...

. In 1951 Leakey and Le Gros Clark placed Hopwood's ''Xenopithecus koruensis'' ("strange ape from

Koru, Kenya Koru is a small town centre in Kisumu County, Kenya, Africa (0.1833° S, 35.2667° E). It forms an electoral ward of Muhoroni Constituency and Muhoroni town council. Koru is also a location in the Muhoroni division. It is at an elevation of 1540m. ...

") with africanus. In 1951 also T. Whitworth found more ''Proconsul'' on Rusinga, which he considered ''africanus'', but they were lumped with 1992 finds by Walker to form ''heseloni''. The 18-million-year-old fossil species has been considered a possible ancestor of both great and lesser apes, and of humans. The paleontologist

Louis Leakey Louis Seymour Bazett Leakey (7 August 1903 – 1 October 1972) was a Kenyan-British palaeoanthropologist and archaeologist whose work was important in demonstrating that humans evolved in Africa, particularly through discoveries made at Olduvai ...

, who was one of the foremost fossil-hunters of the 20th century and a champion of

evolution Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...

, said: Leakey changed his mind a few times about the exact classification of ''Proconsul'', as did most other palaeontologists. Opinion currently favors a position between the monkeys and the apes.

Morphology

''Proconsul africanus'' had a

dental formula 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-physiolo ...

of 2.1.2.3 on both the upper and lower jaws. The molars of this species had thin enamel and there was a prominent molar cingula. This species also possessed a robust

zygomatic bone In the human skull, the zygomatic bone (from grc, ζῠγόν, zugón, yoke), also called cheekbone or malar bone, is a paired irregular bone which articulates with the maxilla, the temporal bone, the sphenoid bone and the frontal bone. It is si ...

and a pronounced snout. This species had a broad

interorbital region The interorbital region of the skull is located between the eyes, anterior to the braincase. The form of the interorbital region may exhibit significant variation between taxonomic groups. In oryzomyine rodents, for example, the width, form, an ...

and small frontoethmoidal sinuses. The

maxillary sinus The pyramid-shaped maxillary sinus (or antrum of Highmore) is the largest of the paranasal sinuses, and drains into the middle meatus of the nose through the osteomeatal complex.Human Anatomy, Jacobs, Elsevier, 2008, page 209-210 Structure It is ...

was restricted. This species had an auditory region which would be similar to that of

extant Extant is the opposite of the word extinct. It may refer to: * Extant hereditary titles * Extant literature, surviving literature, such as ''Beowulf'', the oldest extant manuscript written in English * Extant taxon, a taxon which is not extinct, ...

apes and cercopithecoid monkeys. The ectotympanic tube was well-developed. This species lacked a tail and the canines of this species were

sexually dimorphic Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...

. The skull lacks supraorbital tori and can be considered somewhat

prognathous Prognathism, also called Habsburg jaw or Habsburgs' jaw primarily in the context of its prevalence amongst members of the House of Habsburg, is a positional relationship of the Human mandible, mandible or maxilla to the skeletal base where eithe ...

. This species has a

cranial capacity The size of the brain is a frequent topic of study within the fields of anatomy, biological anthropology, animal science and evolution. Brain size is sometimes measured by weight and sometimes by volume (via MRI scans or by skull volume). Neur ...

of and an

encephalization quotient Encephalization quotient (EQ), encephalization level (EL), or just encephalization is a relative brain size measure that is defined as the ratio between observed to predicted brain mass for an animal of a given size, based on nonlinear regressi ...

of 1.5. Based on the cranium, this species had an external brain surface much like that of

gibbon Gibbons () are apes in the family Hylobatidae (). The family historically contained one genus, but now is split into four extant genera and 20 species. Gibbons live in subtropical and tropical rainforest from eastern Bangladesh to Northeast India ...

s and cercopithecoid monkeys. The wrist of this species has been described as monkey-like. This species has a talus in which the trochlear surface is highly curved and deeply grooved. The foot of this species possessed a transverse arch. ''Proconsul africanus'' had a

brachial index Brachial means "pertaining to the arm", and may refer to: * Brachial artery, in anatomy * Brachial fascia * Brachial lymph nodes * Brachial veins * Brachial plexus, a network of nerves * Brachial valve, the upper valve in Brachiopods * Brachialis m ...

of 96 which is comparable to the extant genus '' Pan''. Overall the skeleton of this species can be described as being robust. This species had an average body mass of around . Based upon the dental morphology, it is conjectured that ''Proconsul africanus'' was a

frugivorous A frugivore is an animal that thrives mostly on raw fruits or succulent fruit-like produce of plants such as roots, shoots, nuts and seeds. Approximately 20% of mammalian herbivores eat fruit. Frugivores are highly dependent on the abundance and ...

species; a study by Aiello in 1981 concluded it was a "below-branch feeder." Based on postcranial pieces, it was likely an

arboreal Arboreal locomotion is the Animal locomotion, 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. Th ...

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 ''quattuor' ...

Discovery

Morphology

References

Other sources

See also