Homo habilis

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Homo habilis
The fossil OH 7 (replica), the holotype of Homo habilis

The fossil OH 7 (replica),
the holotype of Homo habilis

Temporal occurrence
Pleistocene
2.1 to 1.5 million years
Locations
Systematics
Human (Hominoidea)
Apes (Hominidae)
Homininae
Hominini
homo
Homo habilis
Scientific name
Homo habilis
L. Leakey , Tobias & Napier , 1964

Homo habilis is an extinct species of the genus Homo . All thefindsso far designated as Homo habilis come from East African rock layers .

The announcement of the first finds and the naming in April 1964 are considered a "turning point in paleoanthropology ", since previously only hominine fossils of the genus Australopithecus were known from Africa and based on the findings of Homo erectus (until then only in Asia) it was suspected. that the genus Homo developed in Asia.

Naming

The name of the genus Homo is derived from the Latin hŏmō [ ˈhɔmoː ] "man". The epithet habilis also comes from Latin and means “skillful”, “capable”, “gifted”; it was recommended to the authors of the first description by Raymond Dart . Homo habilis therefore means “skillful person” and was chosen because the manufacture of stone tools recovered from similar old horizons was attributed to Homo habilis .

Initial description

The skull KNM ER 1813 from Koobi Fora , Kenya ( replica )
Facial reconstruction in the Westphalian Museum of Archeology , Herne
Colored flags mark the locations of hominine fossils. OH 7 was also discovered in this area.
Memorial stone at the site of OH 7

In the first description by Louis Leakey , Phillip Tobias and John Napier, the holotype of Homo habilis was an approximately 1.75 million year old, completely preserved, toothed lower jaw of a child (OH 7), in which the wisdom teeth had not yet erupted . Jonathan Leakey discovered the fossil OH 7 (called "Johnny's Child") in the fall of 1960; Under this archive number the lower jaw as well as one upper jaw tooth of the associated skull and 13 bones of a youthful hand were combined. A small fragment of the lower jaw with a wisdom tooth ( Molar M3; archive number OH 4 = Olduvai hominid 4) and remains of two other teeth, the fossil OH 8 discovered in 1960 (a group of related foot bones from an individual, probably also not yet adult) , were identified as paratypes. , and some other fossils named. OH 4 had already been found in June 1959 by Heselon Mukiri, a long-time employee of Louis Leakey, in the Olduvai Gorge in northern Tanzania .

In order to be able to assign the newly described species to the genus Homo , the definition of this genus was adapted to the new finds in the first description of Homo habilis . Until then it had been customary to define the boundary between Australopithecus and Homo on the basis of the brain volume, with some researchers 700 cm³, others 750 cm³ or 800 cm³ and - most influential - Ernst Mayr as early as 1950 even 900 cm³ as " cerebral Rubicon ”; in the first description of Homo habilis , however, this lower limit of the brain volume for species of the genus Homo was reduced to 600 cm³.

Only since the 1980s has the species been generally recognized as independent in specialist circles.

More finds

In addition to the finds from the Olduvai Gorge in Tanzania, several fossils from the eastern edge of Lake Turkana ( Kenya ) were attributed to Homo habilis , including the partially preserved skeleton KNM-ER-3735 from Koobi Fora in the northeast of Lake Turkana and the upper jaw, discovered in 1975 AL 666-1 from Hadar in Ethiopia, furthermore South African finds from Sterkfontein (the skull Stw 53 ) and Swartkrans (the skull fragment SK 847).

The accompanying finds (including prehistoric relatives of horses , tapirs and pigs, as well as hippos and otters ) suggest a habitat that consisted of grassy savannahs, watercourses and lakes with riparian trees ( gallery forests ). Stone tools of the Oldowan type as well as animal bones with notches that can be interpreted as cutting marks were found in the fossilized layers ; from this it was concluded that Homo habilis separated meat from the bones and consumed it.

The fossils of Homo rudolfensis also date from the epoch around two million years ago . So far, however, no related finds of bones from the area of ​​his head and his arms and legs have been discovered, so that the physique of Homo rudolfensis below the head is uncertain. However, in the layers of the found layers of the skull bones of Homo rudolfensis, an abundance of individual limb bones and a pelvis were discovered, which differ considerably from Homo habilis and probably belong to Homo rudolfensis .

A distinction between Homo habilis and Homo rudolfensis “ lege artis ” (in accordance with the customs in paleoanthropology) is currently ruled out, as this distinction would have to be based on a comparison of the type specimens of both species. Such a comparison is not possible, however, because OH 7 is a toothed lower jaw , whereas a toothless skull with a partially preserved upper jaw was identified as the type specimen of Homo rudolfensis .

features

Compared to the earlier Australopithecus and Paranthropus , who lived at the same time , Homo habilis had a brain volume of approx. 650 cm³ which was 30% larger (for comparison: Homo sapiens 1200 to 1400 cm³).

Since initially no body bones were found except in connection with the lower jaw OH 7 and the definition of the species in the first description was essentially linked to the structure of the teeth and the jaw, a reliable reconstruction of the anatomical conditions below the head has so far been pending: In the fossils attributed to Paranthropus boisei were found in the same layers . Therefore, the assignment of the bones of the trunk and the limbs to one type or another has not yet been established.

Nevertheless, two isolated leg bones identified as OH 35 were ascribed to Homo habilis in 1982 - and again in 2008 - and “habitual two-leggedness ” was derived from their shape . The height of a female Homo habilis was estimated to be around one meter and the body weight to be 25 to 35 kilograms. Louis Leakey et al. named in the first description at the same time as a further criterion for the affiliation of Homo habilis to Homo the opposable thumb and the precision grip connected with it . Today, however, both statements are questioned: It is possible that Homo habilis only temporarily moved upright, and the alleged precision grip was also questioned.

The hand associated with OH 7 has - as in modern humans - a relatively large thumb and broad fingertips, and the arms are longer than the legs. However, as with chimpanzees , the fingers are relatively long and curved, which indicates they are often in trees. An analysis of the humerus of OH 62 also showed that it has clear chimpanzee-like characteristics and deviates significantly from the characteristics of Homo erectus ; Since other finds from the same strata of the Olduvai Gorge ( Tanzania ) and Lake Turkana ( Kenya ) show some chimpanzee and some human-like features, but their assignment to Homo habilis or Paranthropus boisei cannot be verified, it is still unclear whether the physique of Homo habilis showed mixed characteristics or whether all human-like fossils are to be assigned to Homo , whereas the chimpanzee- like fossils are to be assigned to Paranthropus .

feature Homo habilis Homo rudolfensis
Brain volume approx. 610 cm³ approx. 750 cm³
Bulge above the eye easily developed is missing
upper molars 2 roots 3 roots
lower premolars narrow crowns broad crowns
Wisdom tooth not scaled down scaled down
limbs Pongid- like " Derived " (?)
Thigh like Australopithecus Homo - similar (?)
foot like Australopithecus Homo- like (?)

Dating

All known finds of Homo habilis were dated to an age of approx. 2.1 to 1.5 million years. From when to when a fossil species existed can usually only be determined approximately. On the one hand, the fossil record is incomplete: there are usually only very few specimen copies for a fossil species. On the other hand, the dating methods indicate a certain age, but with considerable inaccuracy ; this inaccuracy then forms the outer limits for the "from ... to" information for lifetimes. All published age information is therefore provisional, which may also have to be revised after further specimen copies have been found.

It is not known why the species became extinct.

Controversy

Tooth from Homo habilis KB 5223 from Kromdraai , South Africa

The classification of the finds called Homo habilis in the genus Homo has been controversial since the first description of this species in April 1964. It took place against the background of the then widely held assumption that only humans - and in a broader sense the species of the genus Homo - are capable of making and using tools; This was programmatically formulated by the British geologist Kenneth P. Oakley in a specialist article in 1944 and in his book Man the Tool-Maker in 1949 . As early as May 1964, however, the first reservations about the naming were published, and a few weeks later the influential British anatomist and paleoanthropologist Wilfrid Le Gros Clark wrote that he hoped that Homo habilis would disappear as quickly as it came.

Alan Walker , a former doctoral student of John Napier, who worked with Richard Leakey in Nairobi in the early 1970s and was thus able to follow the discussion about the habilis finds, criticized in 2011 that the first description in 1964 “was full of speculation about this Behavior and the humanity of Homo habilis . ”He also objected that the bones identified in the first description as belonging to the same juvenile individual (lower jaw, upper jaw tooth and hand bones) had not been discovered close together, the paratypes came from other sites, and all Belonging to the same species is therefore by no means certain. That later made it more difficult to assign additional fossils to Homo habilis ; For example, the fossil OH 62 was placed as Homo habilis due to the characteristics of its teeth and palate , although the bones from the area below the skull were "an upright monkey" and the fossils named Homo habilis probably at least belong to two types. "Although more specimens have now been discovered and assigned to Homo habilis , this species is so ailing that there are no two anthropologists who keep the same list of habilis finds."

The critics of the naming consider the fossils to be Australopithecus due to the characteristics of the teeth , which is why the term Australopithecus habilis (“skillful monkey of the south”) was used in parts of the specialist literature . For example, Bernard Wood wrote in Science in 1999 that "the earliest taxon to meet the criteria [for the genus Homo ] is Homo ergaster or the early African Homo erectus "; In 2011 Wood renewed his criticism.

However, it was accepted by both sides that the habilis fossils closed a temporal and anatomical gap between the Australopithecus variants known up to that point and those of Homo erectus . The finds were often even interpreted to the effect that Homo habilis was a direct ancestor of Homo erectus . Already the find of OH 62 in 1986 and more recent finds raised doubts about this thesis, which was introduced by Louis Leakey and up until then generally held. In 2007, a group led by Meave Leakey and Louise Leakey published a find that was assigned to Homo habilis and was dated to an age of only 1.44 million years. That would mean that Homo habilis and Homo erectus / Homo ergaster coexisted for up to half a million years. The scientists suspect that the two species occupied different ecological niches and were therefore not direct competitors.

It is possible that the opinion, which was sometimes held by researchers in the past, that Homo habilis should be assigned to the Australopithecine species and therefore called Australopithecus habilis, is experiencing a new impetus. For example, a reconstruction of eating habits showed that Homo habilis was closer to Australopithecus than to Homo ergaster / Homo erectus . However, from an analysis of the condition of the tooth KB 5223 from Kromdraai (South Africa), it was concluded that the diet of Homo habilis - unlike that of Australopithecus africanus - consisted to a much greater extent of meat and in this respect resembled the habits of other species of the genus Homo .

A digital reconstruction of the fossil OH 7 published in 2015 showed that the lower jaw with its long and narrow row of teeth is “strikingly primitive ” and resembles Australopithecus afarensis much more than the later Homo erectus . However, with a volume of 729 to 824 cm³, the brain is significantly larger than previously calculated and therefore larger than in the species of the genus Australopithecus ; it is comparable to Homo rudolfensis and Homo erectus .

See also

literature

Web links

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

Individual evidence

  1. ^ Bernard Wood : Fifty years after Homo habilis. In: Nature . Volume 508, No. 7494, 2014, pp. 31-33, doi: 10.1038 / 508031a .
  2. ↑ a b c Randall L. Susman, Jack T. Stern: Functional Morphology of Homo habilis. In: Science . Volume 217, No. 4563, 1982, pp. 931-934, doi: 10.1126 / science.217.4563.931
  3. ↑ LSB Leakey , PV Tobias and JR Napier : A new species of the genus Homo from Olduvai Gorge. In: Nature. 202, 1964, pp. 7-9; doi: 10.1038 / 202007a0 , full text (PDF; 352 kB) .
  4. ^ Ernst Mayr : Taxonomic categories in fossil hominids. In: Cold Spring Harbor Symposia on Quantitative Biology 15. 1950, pp. 109-118; excerpt
  5. ↑ a b For an overview see: Phillip Tobias: The species Homo habilis: example of a premature discovery. In: Annales Zoologici Fennici. Volume 28, 1992, pp. 371-380; Full text (PDF; 5.5 MB) .
  6. ^ A b Gary J. Sawyer, Viktor Deak: The long way to people. Life pictures from 7 million years of evolution. Spektrum Akademischer Verlag, Heidelberg 2008, p. 85. - The mean value is based on the measurement of four individuals whose brain volume was between 590 and 690 cm³.
  7. ^ Randall L. Susman: Brief communication: Evidence bearing on the status of Homo habilis at Olduvai Gorge. In: American Journal of Physical Anthropology. Volume 137, No. 3, 2008, pp. 356-361, doi: 10.1002 / ajpa.20896 .
  8. ^ Francis Clark Howell : Homo habilis in detail. In: Science. Volume 253, No. 5025, 1991, pp. 1294-1295, doi: 10.1126 / science.253.5025.1294 .
  9. ↑ Bernard Wood, Brian G. Richmond: Human evolution: taxonomy and paleobiology. In: Journal of Anatomy . Volume 197, No. 1, 2000, pp. 19-60, doi: 10.1046 / j.1469-7580.2000.19710019.x , PMC 1468107 (free full text).
  10. ↑ Mary W. Marzke: Precision grips, hand morphology, and tools. In: American Journal of Physical Anthropology. Vol. 102, No. 1, 1997, pp. 91-110, doi : 10.1002 / (SICI) 1096-8644 (199701) 102: 1 <91 :: AID-AJPA8> 3.0.CO; 2-G .
  11. ↑ Christopher Ruff: Relative limb strength and locomotion in Homo habilis. In: American Journal of Physical Anthropology. Volume 138, No. 1, 2009, pp. 90-100, doi: 10.1002 / ajpa.20907 .
  12. ↑ taken from: Friedemann Schrenk: Die Frühzeit des Menschen. The way to Homo sapiens. CH Beck, 1997, p. 70.
  13. ↑ 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
  14. ^ Friedemann Schrenk , Ottmar Kullmer and Timothy Bromage : The Earliest Putative Homo Fossils. Chapter 9 in: Winfried Henke and Ian Tattersall : Handbook of Paleoanthropology. Springer Verlag, Berlin and Heidelberg 2007, pp. 1611–1631, doi: 10.1007 / 978-3-540-33761-4_52 .
  15. ↑ Kenneth P. Oakley: Man the Tool Maker. British Museum (Natural History), London 1949.
    Kenneth P. Oakley: Man the Tool-Maker. In: Proceedings of the Geologists' Association. Vol. 55, No. 2, 1944, pp. 115-118, doi: 10.1016 / S0016-7878 (44) 80012-8 .
  16. ↑ Kenneth P. Oakley, Bernard Campbell: Newly Described Olduvai Hominid. In: Nature. 202, 1964, p. 732; doi: 10.1038 / 202732b0 .
  17. ^ Wilfrid Le Gros Clark : Discovery. Volume 25, 1964, p. 49.
  18. ↑ Alan Walker and Pat Shipman: Sex and the Missing Link. Chapter 6 in: The Same: Turkana Boy. In search of the first person. Galila Verlag, Etsdorf am Kamp 2011, p. 132, ISBN 978-3-902533-77-7 .
  19. ↑ Alan Walker and Pat Shipman, Sex and the Missing Link, pp. 161 and 139.
  20. ^ Ian Tattersall : The Strange Case of the Rickety Cossack - and Other Cautionary Tales from Human Evolution. Palgrave Macmillan, New York 2015, p. 83, ISBN 978-1-137-27889-0
  21. ^ Bernard Wood, Mark Collard: The Human Genus. In: Science. Volume 284, No. 5411, 1999, pp. 65-71, doi: 10.1126 / science.284.5411.65 .
    see also: Bernard Wood: Origin and evolution of the genus Homo. In: Nature. Volume 355, 1992, pp. 783-790; doi: 10.1038 / 355783a0 .
  22. ↑ Bernard Wood: Did early Homo migrate “out of” or “in to” Africa? In: PNAS . Volume 108, No. 26, 2011, pp. 10375-10376, doi: 10.1073 / pnas.1107724108 .
  23. ^ Ann Gibbons: New fossils challenge line of descent in human family tree. In: Science. Volume 317, p. 733, August 10, 2007.
  24. ↑ F. Spoor, MG Leakey et al .: Implications of new early Homo fossils from Ileret, east of Lake Turkana, Kenya. In: Nature. Volume 448, 2007, pp. 688-691, doi: 10.1038 / nature05986 .
  25. ↑ Fossils shake the human family tree. On: spiegel.de from August 9, 2007.
  26. ↑ Homo habilis. On: archaeologyinfo.com , dump of September 22, 2016.
  27. ↑ Ann Gibbons: Who was Homo habilis - and was it really Homo? In: Science. Volume 332, No. 6036, 2011, pp. 1370-1371, doi: 10.1126 / science.332.6036.1370 .
  28. ↑ Vincent Balter et al .: Evidence for dietary change but not landscape use in South African early hominins. In: Nature. Volume 489, 2012, pp. 558-560, doi: 10.1038 / nature11349 .
    Early human ancestors had more variable diet. On: eurekalert.org of August 8, 2012
  29. ↑ Fred Spoor et al .: Reconstructed Homo habilis type OH 7 suggests deep-rooted species diversity in early Homo. In: Nature. Volume 519, 2015, pp. 83-86, doi: 10.1038 / nature14224 .
    Digital rebirth of the "skillful person". On: mpg.de from March 4, 2015 (with illustration of the digital reconstruction)