Equatorius

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Equatorius
Replica of a skull

Replica of a skull

Temporal occurrence
middle Miocene
15.5 to 14.0 million years
Locations
Systematics
Monkey (anthropoidea)
Old World Monkey (Catarrhini)
Human (Hominoidea)
incertae sedis
Equatorius
Scientific name
Equatorius
Ward , Brown , Hill , Kelley & Downs , 1999
species
  • Equatorius africanus

Equatorius is an extinct genus of primates that was foundin East Africa during the Middle Miocene . According to the first description of the genus and type species published in 1999, fossils discoveredin Kenya on the edge of the Great African Rift Valley in the Tugen Hills comefrom layers of earth that are 15.5 to 14 million years old.

Naming

The name of the genus was derived from the location Maboko Island in Lake Victoria , not far from the equator . The epithet of the type species and so far the only scientifically described species of the genus, Equatorius africanus , is derived from the Latin africanus (= "African") and refers to the continent of origin. Equatorius africanus therefore means "animal from the African equator".

Initial description

As a holotype of the genus in the first description by Steve Ward et al. the fragment of an upper jaw with the preserved front jaw tooth P3, the adjacent large molar tooth M1 and a tooth root preserved from the molar tooth M2 (archive number BMNH M 16649).

Finds

According to the first description, the trigger for the description of the genus Equatorius was the discovery of the partially preserved skeleton of a presumably male individual (archive number KNM-TH 28860), which was ascribed an age of 15.58 to 15.36 million years. It comes from the BPRP 122 site near Kipsaramon, Baringo District , in the northwestern ridge of the Tugen Hills. Among other things, the almost completely preserved, partially toothed lower jaw , several incisors of the upper jaw, fragments of the shoulder blade , the sternum and several ribs , fragments of both humerus bones , both spokes and ells , various bones of the hands and a completely preserved vertebra were recovered from this fossil .

From the analysis of the teeth and the body bones it was concluded that their characteristics show great similarities with those fossil finds, which until then had been assigned to the species Kenyapithecus africanus introduced by Louis Leakey in 1967 ; those finds also come exclusively from Kenya, partly from the Tugen Hills, partly from the Samburu District . Steve Ward et al. In contrast, came to the conclusion in 1999 that - in the light of the partial skeleton KNM-TH 28860 they discovered - there are such considerable differences between the fossils previously known as Kenyapithecus africanus and those of the type species of the genus Kenyapithecus , Kenyapithecus wickeri , that all these fossils are one own genus - the genus Equatorius - should be assigned. On the basis of this definition, those fossils also belong to Equatorius that were referred to in the older specialist literature as Proconsul africanus , Sivapithecus africanus , Dryopithecus sivalensis , Sivapithecus sivalensis and Griphopithecus africanus , since those finds had previously been combined in the species Kenyapithecus africanus . The partial skeleton KNM-TH 28860 was not described in detail until the beginning of 2002.

As early as 2000, the objection to this approach was that when defining Equatorius , the first description failed to define a precise distinction from Griphopithecus , to which there is a great similarity and whose established generic name has priority over the introduction of a new generic name would have. In addition, the descriptions of individual fossils that were later assigned to Equatorius diverge so significantly that a clear delineation from Kenyapithecus does not seem to have been made, although later fossils were discovered at the same site in the Tugen Hills.

According to the first description, Equatorius africanus is more original than Kenyapithecus wickeri in terms of various characteristics ; It also highlights anatomical features that Equatorius shares with Proconsul and Afropithecus . However, Equatorius was already more adapted to a terrestrial way of life than Proconsul . Based on the dimensions of his bones, it was estimated that the body weight of the individual KNM-TH 28860 was approximately 27 kilograms during his lifetime.

See also

Web links

Individual evidence

  1. ^ A b Steve Ward, Barbara Brown, Andrew Hill, Jay Kelley and Will Downs: Equatorius: A New Hominoid Genus from the Middle Miocene of Kenya. In: Science . Volume 285, No. 5432, 1999, pp. 1382-1386, doi: 10.1126 / science.285.5432.1382
  2. ^ LSB Leakey : An Early Miocene Member of Hominidae. In: Nature . Volume 213, 1967, pp. 155-163, doi: 10.1038 / 213155a0
  3. ↑ Richard J. Sherwood et al .: Preliminary description of the Equatorius africanus next term partial skeleton (KNM-TH 28860) from Kipsaramon, Tugen Hills, Baringo District, Kenya. In: Journal of Human Evolution. Volume 42, No. 1-2, 2002, pp. 63-73, doi: 10.1006 / jhev.2001.0502
  4. ↑ David R. Begun : Middle Miocene Hominoid Origins. In: Science. Volume 287, No. 5462, 2000, p. 2375, doi: 10.1126 / science.287.5462.2375a
  5. ↑ Carol V. Ward: Postcranial and locomotor adaptations of hominoids. In: Winfried Henke , Ian Tattersall (Eds.): Handbook of Paleoanthropology. Springer Verlag, Berlin 2007, p. 1020, ISBN 978-3-540-32474-4
  6. ↑ Jay Kelley et al .: Dental remains of Equatorius africanus from Kipsaramon, Tugen Hills, Baringo District, Kenya. In: Journal of Human Evolution. Volume 42, No. 1-2, 2002, pp. 39-62, doi: 10.1006 / jhev.2001.0504
  7. ^ BA Patel et al .: Terrestrial adaptations in the hands of Equatorius africanus revisited. In: Journal of Human Evolution. Volume 57, No. 6, 2009, pp. 763-772, doi: 10.1016 / j.jhevol.2009.08.005