Paranthropus robustus

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Paranthropus robustus
SK 48 skull of Paranthropus robustus

SK 48 skull of Paranthropus robustus

Temporal occurrence
Upper Pliocene to Pleistocene
1.8 to 1.2 million years
Locations
Systematics
Human (Hominoidea)
Apes (Hominidae)
Homininae
Hominini
Paranthropus
Paranthropus robustus
Scientific name
Paranthropus robustus
( Broom , 1938)

' Paranthropus robustus' is a species of the extinct genus Paranthropus from the line of development of the hominini , which occurred around 1.5 million years ago in southern Africa . The body shape of the species is similar to that of Australopithecus africanus , but Paranthropus robustus had a larger, more powerful skull and more massive teeth and is therefore sometimes called "robust Australopithecus ". The delimitation of the genus Paranthropus from Australopithecus is controversial, which is why the fossils are referred to as Australopithecus robustus by some researchers .

The species of the genus Paranthropus are included in the Australopithecina group and probably represent an evolutionary sideline to the genus Homo .

Naming

Paranthropus is an artificial word . The name of the genus is derived from ancient Greek ἄνθρωπος anthropos , German 'human' and para 'next to', 'deviating from'. The epithet robustus alludes to the 'robust' physique. Paranthropus robustus therefore means “robust fellow human”, in the sense of “arranged in the family tree next to the human species”.

Initial description

Holotype TM 1517 of Paranthropus robustus

The holotype of Paranthropus robustus is a partially preserved skull (archive number TM 1517) that was first described by Robert Broom in August 1938 , the remains of which were discovered two months earlier near Sterkfontein . The discoverer of the skull fragments was a schoolboy, Gert Terblanche, who saw parts of the skull sticking out of the ground on a hill outside the caves of Sterkfontei. Robert Broom, who scientifically supervised the fossil finds in the region, recognized their importance and in the same year attributed the new finds to the newly introduced genus and its type species Paranthropus robustus . Broom deliberately did not place the finds among the pre-humans of the Australopithecus genus .

After cleaning the fragments, they could be joined together to form an almost complete palatal bone with almost all the teeth of the upper jaw and the left half of the skull, and the right half of the lower jaw was recovered. According to the initial description, these findings made it possible to estimate the original size of the skull, which, according to Broom, was larger than the majority of male chimpanzees living today and almost as large as most female gorillas living today . Overall, however, the structure of the skull is very different from that of the great apes living today, and it also deviates from all the characteristics of other fossil genera described so far. The face was very flat and much shorter than that of the gorillas. According to Broom, the brain volume of the type specimen could have been around 600 cm³.

In 1948, in the Swartkrans Cave , which is only about 1.2 kilometers away from Sterkfontein , Broom discovered the fossil SK 6 , consisting of a part of a lower jaw and some teeth, which he initially called Paranthropus crassidens (from Latin: crassus = thick and dens = tooth). However, this additional species designation has not caught on, since it is obviously also Paranthropus robustus . SK 6 is now regarded as the second type specimen for Paranthropus robustus .

More finds

Hypothesis on the evolution of the australopithecines , as represented by Friedemann Schrenk , for example, based on the current finds .

In the following two years, complete skulls were also found in the Swartkrans cave: first in 1949 the fossil with the designation SK 79 , which, however, was heavily crushed by the sediment and was therefore only of limited scientific information. On June 30, 1950, during blasting work in the cave, which was used for the commercial quarrying of limestone, a relatively completely preserved skull with the fossil designation SK 48 was uncovered ( see figure in the taxobox ). This contained a canine , two premolars and a total of five molars in the upper jaw . The skull with its crest , the strong zygomatic arches and the deepened nasal area were important for the characteristic morphology of the robust australopithecines . Broom thought this individual was a female. His anatomical description, which he completed in 1951, appeared posthumously in an extensive monograph.

A particularly well-preserved skull DNH 7 was found in 1994 in the karst caves of Drimolen (South Africa). Other important sites are Coopers Cave near Swartkrans and Gondolin Cave in the Northwest Province .

The sites of the fossils related to Paranthropus robustus have not yet been absolutely dated ; the age data (1.8 to 1.2 million years) are based on auxiliary biostratigraphic dates .

Appearance

Paranthropus robustus was assigned a height of 1.10 to 1.30 m and a weight of 40 to 80 kg. The massive face is flat, without a forehead, and has large eyebrow ridges . It had relatively small incisors and canines , but massive molars in a large lower jaw. Most of the specimens have a crest . These features suggest that his diet may have consisted mostly of coarse, chewy foods that required a lot of chewing. It has been proven that - similar to the earliest representatives of the genus Homo and like Australopithecus africanus - more than 50 percent of its daily caloric intake was fed on C 3 plants and a further significant proportion on C 4 plants .

In almost every second deciduous molar , but not in the incisors and canines , numerous depressions were found in the tooth enamel , which give these teeth a “golf ball-like” appearance - a pattern of damage that is similar to that of amelogenesis imperfecta in humans. The genes associated with this disease in humans are involved in the production of thick, densely packed tooth enamel; Therefore, in a study published in 2019 , it was speculated that the numerous, crater-shaped tooth enamel defects in Paranthropus robustus were a by-product of the acquisition of particularly thick, densely layered tooth enamel in the course of evolution and not a result of individual food consumption in childhood and adolescence.

The average brain size is around 515 cm³ and is therefore around 100 cm³ larger than that of a chimpanzee living today . Bones excavated using Paranthropus robustus skeletons suggest that they may have been used as digging sticks.

There are only a few preserved bones from the area below the head; the existing fragments from the hip joint and knee joint were interpreted to mean that Paranthropus robustus could very probably at least temporarily walk on two legs.

One of the oldest human-like anatomical features, the shape of the anvil in the middle ear , which already for Australopithecus africanus and Paranthropus robustus is busy (at Fossil SKW 18 from Swartkrans) and probably even at the last common ancestor of the shape of the anvil with the chimps differed .

behavior

Retzius stripes on the cross section of a molar of the fossil SKX 21841 of Paranthropus robustus

Paranthropus robustus probably lived in the savannahs and was able to use coarse and tough-fibred plant material there. Some skeleton finds also suggest that it fell victim to larger predators on a regular or occasional basis.

A detailed examination of the teeth of an upper jaw from the Swartkrans Cave with the help of laser ablation showed that this individual must have consumed food that changes with the seasons: at times relatively soft leaves of deciduous trees and at times relatively hard seeds and other plant parts of grass, comparable to the steppe baboons living today . The teeth of three other individuals also provided evidence of a far less specialized and at least temporarily softer diet than had previously been ascribed to them due to the massive molars.

In 2007, a research group analyzed the correlation between skull size and loss of hard tooth substance in 19 skulls and 16 lower jaws, in each of which the molar M3 (“ wisdom tooth ”) had already erupted. It was reported that young male adults (identifiable due to the low loss of dental hard tissue ) had significantly smaller skulls than older male adults (identifiable due to the high loss of dental hard tissue). From this it was concluded that the increase in size in the male Paranthropus robustus lasted well after sexual maturity. This observation was interpreted with reference to recent primates as a result of high social competition among the males, which in turn is often observed in recent species when a male dominates a group of females (“harem”) and other males keep away from this group tries. With the help of the Retzius stripes on several teeth, it was possible to understand that the enamel formation in Paranthropus robustus took place more quickly than in anatomically modern humans.

According to a study published in 2011, the male individuals were largely localized from birth , while the females immigrated from other populations , which was interpreted as an indication of exogamy ; Female exogamy and male local loyalty also exist in the chimpanzees , while in the gorillas male and female individuals migrate equally to other populations after sexual maturity.

See also

Web links

Commons : Paranthropus robustus  - Collection of images, videos and audio files

Individual evidence

  1. ↑ Paranthropus robustus. On: humanorigins.si.edu , accessed July 24, 2018.
  2. ^ Robert Broom : The Pleistocene Anthropoid Apes of South Africa. In: Nature . Volume 142, No. 3591, 1938, pp. 377–379, doi: 10.1038 / 142377a0 , full text (PDF)
  3. ^ Robert Broom : The Pleistocene Anthropoid Apes of South Africa. In: Nature . Volume 142, No. 3591, 1938, pp. 377-379, doi: 10.1038 / 142377a0 , full text (PDF) .
  4. ^ Robert Broom: Another new type of fossil ape-man. In: Nature. Volume 163, 1949, p. 57, doi: 10.1038 / 163057a0 .
  5. ↑ This is the result of a morphometric comparison of fossils from Kromdraai and Swartkrans by Zachary Cofran and J. Francis Thackeray in 2010 : One or two species? A morphometric comparison between robust australopithecines from Kromdraai and Swartkrans. In: South African Journal of Science. Volume 106, No. 1/2, 2010, Art. # 15, 4 pages, doi: 10.4102 / sajs.v106i1 / 2.15 , full text (PDF) ( Memento from February 11, 2015 in the Internet Archive ).
  6. ↑ JT Robinson: The dentition of the Australopithecinae. Transvaal Museum Mem., Volume 9, Pretoria 1956.
  7. ↑ Robert Broom: Swartkran's Ape-Man, Paranthropus crassidens. In: Transvaal Museum Mem. Volume 6, Pretoria 1952.
  8. ^ André W. Keyser: The Drimolen skull: the most complete australopithecine cranium and mandible to date. In: South African Journal of Science. Volume 96, 2000, pp. 189–193, full text (PDF; 641 kB)
  9. ^ Coopers Cave website ( Memento of September 7, 2008 in the Internet Archive ) (accessed on March 17, 2012).
  10. ↑ Menter, CG; Kuykendall, KL; Keyser, AW; Conroy, GC: First record of hominid teeth from the Plio-Pleistocene site of Gondolin, South Africa. In: Journal of Human Evolution. Volume 37, 1999, pp. 299-307 doi: 10.1006 / jhev.1999.0329 .
  11. ↑ Gary J. Sawyer, Viktor Deak: The Long Way to Man. Life pictures from 7 million years of evolution. Spektrum Akademischer Verlag, Heidelberg 2008, ISBN 978-3827419156 , p. 73.
  12. ^ The Cambridge Encyclopedia of Human Evolution. Cambridge University Press, 1992, p. 236.
  13. ^ Peter S. Ungar, Matt Sponheimer: The Diets of Early Hominins. In: Science . Volume 334, No. 6053, 2011, pp. 190–193, doi: 10.1126 / science.1207701 .
  14. ↑ Disorder left ancient human relative with teeth pocked like golf balls. On: sciencemag.org of March 7, 2019
  15. ↑ Ian Towle and Joel D. Irish: A probable genetic origin for pitting enamel hypoplasia on the molars of Paranthropus robustus. In: Journal of Human Evolution. Volume 129, 2019, pp. 54-61, doi: 10.1016 / j.jhevol.2019.01.002
  16. ^ Gary J. Sawyer, Viktor Deak, The Long Road to Humans, p. 71.
  17. ↑ Bernard Wood , Nicholas Lonergan: The hominin fossil record: taxa, grades and clades. In: Journal of Anatomy . Volume 212, No. 4, 2008, p. 360, doi: 10.1111 / j.1469-7580.2008.00871.x , full text (PDF; 292 kB) ( Memento from October 29, 2013 in the Internet Archive )
  18. ^ Rolf M. Quam et al .: Early hominin auditory ossicles from South Africa. In: PNAS . Online advance publication of May 13, 2013, doi: 10.1073 / pnas.1303375110 .
  19. ^ Matt Sponheimer et al .: Isotopic Evidence for Dietary Variability in the Early Hominim Paranthropus robustus. In: Science. Volume 314, No. 5801, 2006, pp. 980-982, doi: 10.1126 / science.1133827 .
    Not Just Nuts and Berries for These Hominids. On: sciencemag.org of November 9, 2006.
  20. ↑ teeth of individuals SK 24605, SK 24606, SKX 5939 and SKW 6427 were analyzed. Similar findings were reported by Robert S. Scott et al .: Dental microwear texture analysis shows within-species diet variability in fossil hominins. In: Nature. Volume 436, 2005, pp. 693-695, doi: 10.1038 / nature03822 .
  21. ↑ Charles A. Lockwood et al .: Extended Male Growth in a Fossil Hominin Species. In: Science. Volume 318, No. 5855, 2007, pp. 1443–1446, doi: 10.1126 / science.1149211 .
  22. ↑ Ann Gibbons: Hominid Harems: Big Males Competed for Small Australopithecine Females. In: Science. Volume 318, No. 5855, 2007, p. 1363, doi: 10.1126 / science.318.5855.1363a .
  23. ↑ Rodrigo S. Lacruz, Fernando Ramirez Rozzi and Timothy G. Bromage : Variation in enamel development of South African fossil hominids. In: Journal of Human Evolution. Volume 51, 2006, pp. 580-590, doi: 10.1016 / j.jhevol.2006.05.007 , full text (PDF) .
  24. ↑ Sandi R. Copeland et al .: Strontium isotope evidence for landscape use by early hominins. In: Nature. Volume 474, No. 7349, 2011, pp. 76-78, doi: 10.1038 / nature10149 .
    Teeth reveal a lot about the life radius of early ancestors. On: mpg.de from June 1, 2011.