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Proconsul

Cladus: Eukaryota
Supergroup: Opisthokonta
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Cladus: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Superclassis: Tetrapoda
Classis: Mammalia
Subclassis: Theria
Infraclassis: Placentalia
Ordo: Primates
Subordo: Haplorrhini
Infraordo: Simiiformes
Parvordo: Catarrhini
Superfamilia: †Proconsuloidea
Familia: Proconsulidae
Subfamilia: Proconsulinae
Genera: Proconsul
Species: P. africanus - P. heseloni - P. major - P. nyanzae
[list of genera after Harrison (2005: 45, table 3)]

Proconsul is an extinct genus of primates that existed from 23 to 5 million years ago during the Miocene epoch. Fossil remains are present in Eastern Africa including Kenya and Uganda. Four species have been classified to date: P. africanus, P. heseloni, P. major and P. nyanzae. The four species differ mainly in body size. Environmental reconstructions for the Early Miocene Proconsul sites are still tentative and range from forested environments to more open, arid grasslands.

They had a mixture of Old World monkey and ape characteristics, so their placement in the ape superfamily Hominoidea is tentative, with some scientists placing Proconsul outside of it before the split of the apes and Old World monkeys.

Proconsul's monkey-like features include pronograde postures, indicated by a long flexible back, curved metacarpals, and an above-branch arboreal quadrupedal positional repertoire. The primary feature linking Proconsul with extant apes is its lack of a tail; other "ape-like" features include its enhanced grasping capabilities, stabilized elbow joint and facial structure. Proconsul was definitely not suspensory like modern apes.

Discovery and classification

The first specimen, a partial jaw discovered in 1909 by a gold prospector at Koru, near Kisumu in western Kenya, was also the oldest fossil hominoid known until recently, and the first fossil mammal ever found in sub-Saharan Africa. The name, Proconsul, was devised by Arthur Hopwood in 1933[1] and means "before Consul". At the time Consul was being used as a circus name for performing chimpanzees. The Folies Bergère of 1903 in Paris had a popular performing chimpanzee named Consul, and so did the Belle Vue Zoo in Manchester, England, in 1894. On the latter's death in that year Ben Brierley wrote a commemorative poem wondering where the "Missing Link" between chimpanzees and men was.[2]

Hopwood in 1931 had discovered the fossils of three individuals while expeditioning with Louis Leakey in the vicinity of Lake Victoria. The Consul that he selected to use in the name was neither of the ones mentioned above, but another located in the London Zoo. Consul is being used Linnaean-style to symbolize the chimpanzee. Proconsul is therefore "ancestral to the Chimpanzee" in Hopwood's words. He also added africanus as the species name. It was the only one known at the time .

Other fossils discovered later were initially classified as africanus and subsequently reclassified; that is, the total pool of fossils originally considered africanus was "split" and the fragments "lumped" with other finds to create a new species. For example, Mary Leakey's famous find of 1948 began as africanus and was split from it to be lumped with Thomas Whitworth's finds of 1951 as heseloni by Alan Walker in 1993. This process creates some confusion for the public, which is told that africanus became heseloni. The finds from Koru and Songhor are still considered africanus. Four species are still defined even though many fossils have jumped species .
Restoration

The family of Proconsulidae was first proposed by Louis Leakey in 1962 , eleven years after he and Wilfrid Le Gros Clark had defined africanus, nyanzae and major. It was not immediately accepted but ultimately prevailed.

The history of hominoid classification in the second half of the 20th century is sufficiently complex to warrant a few books itself. Most of the palaeoanthropologists have changed their minds at least once as new fossils have come to light and new observations have made, and will probably continue to do so. The classifications found in the literature of one decade are not generally the same as those of another.[3] For example, in 1987 Peter Andrews and Lawrence Martin, established palaeontologists, took the point of view that Proconsul is not a Hominoid, but is a sister taxon to it.[4]
Notes
Proconsul africanus skull

^ Virginia Morell, Ancestral Passions, Copyright 1995
^ The ape in the tree: an intellectual & natural history of Proconsul
^ A recapitulation of the changing classifications of fossils at some time regarded as Proconsul can be found in Seven Decades of East African Miocene Anthropoid Studies, by Russel H. Tuttle, in Human Origins and Environmental Backgrounds, Springer, 2006, ISBN 0387296387. Much of the section is to be found as an online review at Google Books.
^ Cladistic relationships of extant and fossil hominoids, abstract of article in Journal of Human Evolution Volume 16, Issue 1, January 1987, Pages 101-118. They also believed at that time that humans and African apes formed distinct clades.

References

Walker, Alan; Shipman, Pat (2005), The APE in the TREE: An Intellectual & Natural History of Proconsul, Cambridge, Massachusetts, London, England: The Belknap Press of Harvard University Press, ISBN 0-674-01675-0 (A preview with excerpt)

External links

Anthropoidea - monkeys and apes, Mikkos's Phylogeny Archive
Comparative dental development and microstructure of Proconsul teeth from Rusinga Island, Kenya, research article by A. D. Beynon et al. at the University College London site.
Walker, Alan, an extensive Proconsul bibliography in the publications of Walker listed at the isiknowledge.com site. Many of these are on line; however, this is a subscription site only.

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Source: Wikipedia , Wikispecies: All text is available under the terms of the GNU Free Documentation License