Homo rudolfensis

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Homo rudolfensis
Replica of the skull of KNM-ER 1470

Replica of the skull of KNM-ER 1470

Temporal occurrence
Pleistocene
2.5 to 1.9 million years
Locations
Systematics
Human (Hominoidea)
Apes (Hominidae)
Homininae
Hominini
homo
Homo rudolfensis
Scientific name
Homo rudolfensis
Alexeev , 1986

Homo rudolfensis is an extinct species in the genus Homo . It is considered the most original species of this genus described so far. Fossils that have beeninterpretedas Homo rudolfensis are around two million years old and come from East Africa .

Naming

The name of the genus Homo is derived from the Latin hŏmō [ ˈhɔmoː ] "man". The epithet rudolfensis refers to the place where it was found at Lake Rudolf (now Lake Turkana ) in Kenya . Homo rudolfensis therefore means “man from Rudolfsee”.

The total modest number of findings led to the fact that because of the time and morphological proximity to australopiths the designation Australopithecus rudolfensis has been suggested, further, the designations Kenyanthropus rudolfensis (because of the potentially extremely flat facial skeleton; comp. Kenyanthropus ) and Pithecanthropus rudolfensis ( based on Haeckel's hypothetical prehistoric man Pithecanthropus primigenius ). "Despite the incomplete findings, there is little doubt that Homo rudolfensis belongs to the human lineage."

Initial description

Holotype of Homo rudolfensis is a severely scraped and toothless skull with a partially preserved upper jaw , but without a lower jaw , with catalog number KNM-ER 1470 (see figure above right), found in 1972 under the direction of Richard Leakey by Bernard Ngeneo at Koobi Fora . This skull was first scientifically described by Richard Leakey in 1973, but initially not assigned to a species previously named, but only assigned to the genus Homo . In 1976, Leakey speculated that the skull could be assigned to Homo habilis . It was not until 1986 that the skull was finally identified in a book by Valerii Alexeev (Валерий Павлович Алексеев) as Homo rudolfensis ; In 1992 the classification of the species on the basis of a line of development leading to anatomically modern humans was postulated. Nevertheless, in 2001 it was considered to assign the skull KNM-ER 1470 to the newly described species Kenyanthropus platyops .

A special feature of the first description is that the skull KNM-ER 1470 was named as a holotype without Alexeev having compared the original fossil with other fossils. In addition, in his book published in 1986, Alexeev used a terminology that was only used in specialist literature before 1950. He called Homo heidelbergensis as "Pithecanthropus heidelbergensis", Homo soloensis as "Pithecanthropus soloensis", and for the skull KNM-ER 1470 he chose the species name "Pithecanthropus rudolfensis", although the genus Pithecanthropus has been an obsolete synonym for the for more than 30 years Genus Homo was considered; Only since Bernard Wood used the name Homo rudolfensis in a research report in 1991 is the species - under this name - widely recognized.

The location of the finds is the Kenyan National Museum in Nairobi ; KNM stands for the museum, ER for East Rudolf, the east bank of Lake Turkana.

More finds

Whether the features of the fossil KNM-ER 1470 were characteristic of its entire population or just a special feature within a species rich in forms could not be clarified at first. It was not until the findings of the upper jaw KNM-ER 62000 and the partially dentate lower jaw KNM-ER 60000, published in 2012, that clarity was brought about by showing that several very similar individuals existed.

Further finds that are attributed to Homo rudolfensis were made in the immediate vicinity of the type specimen (the lower jaw KNM-ER 1802) as well as in Ethiopia ( Omo area ) and Malawi . In Malawi, the German paleoanthropologist Friedemann Schrenk found the lower jaw UR 501 in 1991, which was calculated to be 2.5 million years old. Based on this dating, Homo rudolfensis can be interpreted as the oldest representative of the genus Homo .

It is not known why the species became extinct.

features

The second oldest fossil of the genus Homo: the lower jaw UR 501 (original, Schrenk collection in the Senckenberg Natural History Museum )
UR 501, side view ( replica )

The brain volume of Homo rudolfensis is about 750 cm³; the arrangement of the teeth in the upper and lower jaw, as well as the shape of both jaws, is in many ways similar to that of Paranthropus . Since the skull finds were heavily fragmented, it initially remained unclear whether the rather long face and the lower jaw were arranged prognathically (protruding forward) or more orthognathically (vertically); there is no bulge above the eye . It was not until the upper jaw KNM-ER 62000, in which the palatal bone and the anterior facial bones were also preserved, that the pronounced orthognathy was confirmed and showed striking similarities with the fossil KNM-ER 1470; the finds from the same epoch and attributed to Homo habilis are, however, clearly prognostic. The well-preserved lower jaw KNM-ER 60000 comes from another individual, but because of its arch shape, it basically “fits” the fossil KNM-ER 1470 and was therefore ascribed to the same species.

So far, no related skeletal finds of Homo rudolfensis have been known, so that its physique below the head is unsecured. However, in the same Fund layers a wealth of individual were extremities -Bone and a pool discovered (VSN LMN-ER 3228), significantly different from themselves Australopithecus - differ finds and more similar to those of modern humans. If these finds belong to Homo rudolfensis (which is probable insofar as no other tooth or skull finds from these strata are known that could belong to a parallel species of the genus Homo ), then “the species stood frequently and for a long time away upright ”. The body height of KNM-ER 1472 and KNM-ER 1481 would have been almost 150 cm, the body weight almost 50 kg; for the thigh bone KNM-ER 3728 the reconstruction of the complete individual would result in a height of 145 cm and a weight of 45 kg.

So far, no stone tools have been discovered in direct connection with fossils of Homo rudolfensis , but they were found in slightly more recent horizons on western Lake Turkana. Therefore, it is not certain but is considered possible that Homo rudolfensis , the first Homininus was the stone tools used. Based on dental examinations, it is assumed that Homo rudolfensis was "predominantly herbivorous". Accompanying finds (including relatives of gazelles , elephants and jackals , but also of hippos and baboons ) indicate that the habitat of Homo rudolfensis featured a varied mixture of open, savannah-like grasslands and gallery forests with dense undergrowth.

A differentiation between Homo rudolfensis and Homo habilis “ lege artis ” (according to the customs in paleoanthropology) is currently ruled out, since this demarcation would have to be based on a comparison of the type specimens of both species. Such a comparison is not possible, however, since the type specimen of Homo rudolfensis was determined to be a skull with an edentulous upper jaw, whereas the type specimen of Homo habilis was a toothed lower jaw.

feature Homo rudolfensis Homo habilis
Brain volume approx. 750 cm³

estimated

approx. 610 cm³
Bulge above the eye is missing easily developed
upper molars 3 roots 2 roots
lower premolars broad crowns narrow crowns
Wisdom tooth scaled down not scaled down
limbs "derived"

no clear findings

Pongid- like
Thigh Homo - similar (?) like Australopithecus
foot Homo- like (?) like Australopithecus

Dating

In the first publication, 1973, the skull KNM-ER 1470 was assigned an age of 2.6 million years; later measurements corrected this figure to 1.9 million years. These measurements are considered to be very reliable because all the fossils of Homo rudolfensis in Koobi Fora lie between two volcanic ash layers, the ages of which have been determined to be 1.9 and 1.88 million years. The lower jaw UR 501 from Malawi, which is also related to Homo rudolfensis , is much older and has been calculated to be 2.5 million years old.

nutrition

Even after millions of years, the composition of carbon and oxygen isotopes in tooth enamel samples can be used to reconstruct which foods the individual has eaten. In particular, it is possible to differentiate the consumed proportions of C 3 plants and C 4 plants by geochemical analyzes . According to a study published in 2018, Homo rudolfensis ate 60 to 70 percent of C 3 plants: “These were probably primarily parts of trees, for example their fruits, leaves and tubers. Considerably fewer plant components were consumed, which today dominate the open African savannahs. "

See also

literature

Web links

Commons : Homo rudolfensis  - collection of images, videos and audio files
Wiktionary: Homo rudolfensis  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. ↑ a b Valerii P. Alexeev: The Origin of the Human Race. Progress Publishers, Moscow 1986. Reprint of pages 89-94 relevant to Homo rudolfensis in: W. Eric Meikle, Sue Taylor Parker: Naming our Ancestors. An Anthology of Hominid Taxonomy. Waveland Press, Prospect Heights (Illinois) 1994, ISBN 0-88133-799-4 , pp. 143-147.
  2. ↑ Bernard Wood and Mark Collard: The Human Genus. In: Science . Volume 284, No. 5411, 1999, pp. 65-71, doi: 10.1126 / science.284.5411.65 .
  3. ↑ Gary J. Sawyer, Viktor Deak: The Long Way to Man. Life pictures from 7 million years of evolution. Spektrum Akademischer Verlag, Heidelberg 2008, p. 83.
  4. ^ Richard Leakey : Evidence for an Advanced Plio-Pleistocene Hominid from East Rudolf, Kenya. In: Nature . Volume 242, 1973, pp. 447-450, doi: 10.1038 / 242447a0
  5. ^ Richard E. Leakey: Hominids in Africa . In: American Scientist . tape 64 , no. 2 , 1976, p. 174-178 , JSTOR : 27847157 .
  6. ^ Bernard Wood: Origin and evolution of the genus Homo. In: Nature. Volume 355, 1992, pp. 783-790, doi: 10.1038 / 355783a0 .
  7. ↑ Meave Leakey , Fred Spoor, Frank H. Brown et al .: New hominin genus from eastern Africa shows diverse middle Pliocene lineages. In: Nature . Volume 410, 2001, pp. 433-440, doi: 10.1038 / 35068500 .
  8. ^ W. Eric Meikle, Sue Taylor Parker: Naming our Ancestors. An Anthology of Hominid Taxonomy. Waveland Press, Prospect Heights (Illinois) 1994, ISBN 0-88133-799-4 , p. 142.
  9. ^ Bernard Wood: Koobi Fora Research Project. Volume 4: Hominid cranial remains. Clarendon Press, Oxford 1991.
  10. ^ A b Meave Leakey et al .: New fossils from Koobi Fora in northern Kenya confirm taxonomic diversity in early Homo. In: Nature. Volume 488, 2012, pp. 201-204, doi: 10.1038 / nature11322 .
  11. ↑ New Kenyan fossils shed light on early human evolution , eurekalert.org of August 8, 2012.
  12. ↑ Fossil finds from Kenya bring new insights into the development of the genus Homo , eva.mpg.de from August 8, 2012.
  13. ↑ palaeo.net ( Memento from February 20, 2006 in the Internet Archive ): Homo rudolfensis (UR 501)
  14. ↑ GJ Sawyer, Viktor Deak: The long way to people ... , p. 79.
  15. ^ New Fossils Put Face on Mysterious Human Ancestor. On: sciencemag.org of August 8, 2012.
  16. ↑ a b G. J. Sawyer, Viktor Deak: The long way to people ... p. 81.
  17. ↑ Friedemann Schrenk : The early days of man. The way to Homo sapiens. CH Beck, Munich 1997, p. 72.
  18. ↑ taken from: Friedemann Schrenk: Die Frühzeit des Menschen. The way to Homo sapiens. CH Beck, 1997, p. 70.
  19. ↑ Due to the mostly poor state of preservation, the information on the brain volume varies depending on the fossils used. Sawyer & Deak (p. 85) mention a range of 590 to 687 cc.
  20. ↑ "KNM-ER 1470" , talkorigins.org.
  21. ↑ Tina Lüdecke, Ottmar Kullmer, Ulrike Wacker, Oliver Sandrock, Jens Fiebig, Friedemann Schrenk and Andreas Mulch: Dietary versatility of Early Pleistocene hominins. In: PNAS. Volume 115, No. 52, 2018, pp. 13330-13335, doi: 10.1073 / pnas.1809439115 .
  22. ↑ You are what you eat: Early prehistoric humans had an extremely flexible diet. On: idw-online.de from December 13, 2018.