Lower jaw by brick wall

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The lower jaw of Mauer (original).
The two left premolars were lost due to improper storage during World War II .

The lower jaw of Mauer is the oldest fossil of the genus Homo that has been recovered in Germany . It was discovered in 1907 around ten kilometers south-east of Heidelberg in the sand pit of the community of Mauer . The lower jaw of Mauer is the type specimen of the species Homo heidelbergensis . European researchers also refer to the find as Homo erectus heidelbergensis and thus classify it as a subspecies of Homo erectus . The age of the lower jaw could be absolutely dated for the first time in 2010 and should therefore be 609,000 ± 40,000 years. Previously, based on relative dating methods, an age of either around 600,000 or around 500,000 years was considered likely in the scientific literature .

Find history

Otto Schoetensack and Daniel Hartmann Otto Schoetensack and Daniel Hartmann
Otto Schoetensack and Daniel Hartmann

On 21 October 1907, the blesmol put Daniel Hartmann (1854-1952) in the Bausandgrube in Won Count Rain the church wall 24.63 meters below the former ground level with his shovel a lower jaw free, in which he recognized the remains of a man. He was able to do this because the Heidelberg private scholar Otto Schoetensack (1850–1912) had urged the workers in the sand pit to look out for fossils for 20 years after the well-preserved skull of a forest elephant was discovered in this sand pit in 1887 . Schoetensack had also taught the workers the appearance of human bones using recent examples and often checked the sand pit “for traces of human beings”.

The lower jaw was thrown through the air while shoveling sand and was only discovered after it had already broken in half in two. At the same time, a piece split off on the left side, which was not found later either. In addition, “next to and on the canine and molar teeth of the lower jaw, thick, solidified crusts of fairly coarse sand, a characteristic of the fossils from the Mauerer sands, adhered. The cementing is done by carbonate of lime. On the left half of the jaw, on the premolars and first two molars , firmly attached to the sand, there was a six-centimeter-long and four-centimeter wide scree of limestone, presumably shell limestone. "

Schoetensack was immediately informed of the find by the leaseholder of the sand pit. He examined the site and the lower jaw and presented the results of his studies in the autumn of the following year in a monograph , which he gave the title: "The lower jaw of Homo Heidelbergensis from the sands of Mauer near Heidelberg". On November 19, 1907 Schoetensack had already stated in a notarized document that the mine leaseholder Josef Rosch (1838 to 1925) the Fund as a donation to the University of Heidelberg leave; The lower jaw is still kept in their geological and palaeontological institute. Today it is "the most valuable item in the natural science collections of Heidelberg University". On the right inner side of the lower jaw in the area of ​​the joint, the collection number of the fossil is noted in small capitals in black : “GPIH 1” and underneath “WALL 1”.

Other findings in the sand pit wall are from 1924 by Karl Friedrich Hormuth (1904-1992) discovered chert artifacts, as tools of Homo heidelbergensis are interpreted, and the 1933 Wilhelm Freudenberg (1881-1960) discovered frontal bone fragment which can possibly also be attributed to Homo heidelbergensis .

Find description

Title page of the first description

The anatomical analysis presented in 1908 in the first description of Mauer's lower jaw by Otto Schoetensack was based essentially on the expertise of the Breslau university professor Hermann Klaatsch ; but this was only hinted at in a brief acknowledgment in their foreword.

In his first description, Schoetensack wrote that the “peculiarity of our object” emerges “at first glance” because “a certain disproportion between the jaw and the teeth” is unmistakable: “The teeth are too small for the bone. The existing space would allow them to develop in a completely different way. ”And it goes on to say about the find:

"It shows a combination of features as recenten been neither an even fossil human mandible has been encountered. Even the expert would not be offended if he was hesitant to recognize it as human: Is it completely missing that characteristic which is considered specifically human, namely an external protrusion of the chin region , and yet this defect is combined with extremely strange dimensions of the lower jaw body (...). The absolutely certain proof that we are dealing with a human part lies only in the nature of the dentition . The completely preserved teeth bear the stamp 'human' for evidence : The Canini show no trace of a stronger expression than the other tooth groups. Overall, these are characterized by the moderate and harmonious training that modern mankind possesses. "

Characteristic of the lower jaw are, on the one hand, the missing chin and, on the other hand, the considerable dimensions of the lower jawbone, on which a fourth molar could have been placed behind the wisdom tooth. Since the 3rd molar (the so-called wisdom tooth ) is also present, but the dentin is only exposed in a few places, the age at the onset of death is estimated to be around 20 to 30 years.

Schoetensack concluded from the similarity of the dentition that it was related to contemporary humans ( Homo sapiens ) and therefore placed the lower jaw in the genus Homo - a point of view that is still unanimously held by paleoanthropologists today. From the fact that the lower jaw - in contrast to modern humans - lacks the chin , among other things , Schoetensack derived the justification to define a new species with the species epithet heidelbergensis . Through the subtitle of his first description - “A contribution to the paleontology of man” - Schoetensack also took a clear position on the part of Darwinism “in the great debate of his time about the origin of man: namely that man developed out of the animal kingdom and not even as a finished being is due to a biblical act of creation. "

Schoetensack commented only cautiously on the exact position of the lower jaw of Mauer in the ancestral chain of modern humans: In his study he wrote cautiously that "it seems possible that Homo Heidelbergensis belongs to the ancestral line of European humans" and - after detailed comparisons with it other European fossils - equally vague elsewhere: "We must therefore call the mandibula of Homo Heidelbergensis preneandertaloid." The classification of the lower jaw of Mauer in the time before the Neanderthals turned out to be correct.

Was wrong Schoetensack - like many of his colleagues around the turn of the 20th century - but with the estimation of kinship proximity of the lower jaw of wall with the apes (hominids): recognize the original position "The mandible of Homo heidelbergensis leaves that the common ancestor of Mankind and the great apes. ”In 1924 the oldest fossil from the hominid group was discovered in what is now South Africa - the child of Taung - which is around two million years older than the lower jaw of Mauer and despite its great age not on the common one Base of humans and great apes.

Dating

Sediment layers on the edge of the pit in 2007

Otto Schoetensack had the site of the find marked on the bottom of the sand pit with a memorial stone on which a horizontal line represented the level of the find. It is not known whether his wish was fulfilled, this stone should remain in place, even if the sand pit is one day backfilled; in fact, the part of the pit in which the lower jaw came to light was filled with overburden in the 1930s, then renatured as arable land and declared a nature reserve in 1982; the site is therefore no longer accessible to research. An absolute dating of the place of discovery with the help of modern scientific methods has therefore been impossible so far. As an alternative, repeated attempts have been made to at least limit the age of the fossil with the help of stratigraphic methods .

The found layer, which is only ten centimeters thick, had already been described by Schoetensack as "a layer of rubble, somewhat cemented by carbonate of lime, with very thin layers of Latvian, which boils slightly with HCl". Above and below the find layer, sand was stored in various delimitable layers and other material that had been deposited on the edge of an earlier Neckar arch over the course of thousands of years . In the foreword of his study it says: “The age of these sands is generally given as old diluvial according to the mammal remains found in them ; however, some of the species represented therein also show clear relationships with the youngest periods of the Tertiary , the Pliocene . ”According to today's dating, this would mean a lower age limit of around 780,000 years and an upper limit of several million years.

Although Schoetensack describes in detail numerous fossil animal species, the remains of which were found in the sand pit, he apparently did not attempt to search specifically for fossils in what he called "Layer 4" of the lower jaw. Instead, he cites pages of finds in his work that are apparently not able to be assigned to certain find layers. Relative dating based on accompanying finds is therefore not possible on the basis of the material presented by him.

In the scientific commemorative publication published in 2007 on the 100th anniversary of the discovery, it was therefore lamented that "for the geological determination of the age of the lower jaw of Homo heidelbergensis still no satisfactory exact data were available." Using small fossils from Mauer, the age of the Mauerer sands has been able to determine the age of the Mauerer sands since 1995 increasingly better localized; In addition, an attempt was made to carry out an absolute dating in neighboring sand pits that were still accessible. To date, however, the researchers have not been able to agree which of several possible layers, each belonging to the Cromer warm period, are identical to the layer found in the Grafenrain mine. So it happens that the community of Mauer ascribes an age of "more than 600,000 years" to the find on its website, whereas the memorial stone mentions an age of 500,000 years. A range of 474,000 to 621,000 years is currently considered certain for the age of "Layer 4", with the fossil either coming from the younger range (around 500,000) or the older (around 600,000).

In November 2010 the Proceedings of the National Academy of Sciences published a dating of grains of sand with the help of infrared radiofluorescence (IR-RF) and a dating of teeth with the help of a combined electron spin resonance and uranium-thorium dating , from which an age of the fossil of 609,000 ± 40,000 years was derived.

Kinship with modern man

Replica of the lower jaw of the wall, side view to the left.

The lower jaw of Mauer is the type specimen for the species Homo heidelbergensis . "The anatomical relationships are clearly more primitive than in Neanderthals , but with a harmoniously rounded dental arch and complete row of teeth already 'typically human'." From this fact - on the one hand the delimitation from the later Neanderthals, on the other hand from the older fossil finds known as Homo erectus - becomes Even today, numerous researchers derive the right to assign the lower jaw to an independent chronospecies : For example, according to Chris Stringer , Homo heidelbergensis stands between Homo erectus on the one hand, Neanderthals and Homo sapiens on the other, and from this point of view is the last common ancestor of Neanderthals and anatomically modern humans.

Other researchers counter that the phylogenetic development in Africa and Europe progressed from Homo erectus to the Neanderthal finds made about Homo heidelbergensis ; every boundary being drawn is arbitrary, which is why these researchers refrain from using the name Homo heidelbergensis . You therefore also classify the lower jaw of Mauer as a local (European) late form of Homo erectus .

However, there is consensus in paleoanthropology that the lower jaw of Mauer does not belong to the immediate ancestral line of modern humans. Rather, it is considered to be a descendant of an early settlement in Europe and Asia (depending on the terminology chosen by Homo erectus or Homo heidelbergensis ), the oldest fossil finds outside of Africa are around 1.8 million years old. The last descendants of this first settlement in Europe were the Neanderthals, who died out around 40,000 years ago. Only in a second wave of expansion of the genus Homo , 40,000 to 30,000 years ago, members of the species Homo sapiens , whose descendants are today's humans, penetrated Europe.

habitat

Memorial stone for Daniel Hartmann, unveiled in 1977, on the occasion of the seventieth return of his discovery of the lower jaw of Mauer on October 21, 1907, not far from this memorial stone.

As uncertain as the exact dating of the lower jaw of Mauer was until recently, the assignment of other fossils to its find layer is still uncertain. Such accompanying fossils, however, are the only immediate clues to be able to reconstruct the habitat of a find. It was not until 1991 that two research wells were drilled in the disused Grafenrain sand pit. Furthermore, since 1995, several dozen cubic meters of sand have been sifted in search of small fossils that could provide information about the species that were then located there. However, the mouse teeth actually discovered were not suitable for a more precise dating of the find layer, as these mice lived anatomically almost unchanged for too long. Based on pollen analysis findings in similar vegetation areas, the habitat during the Cromer Warm Period can at least be described “by alluvial forests in the river plains, forest on the slopes and open forest on the heights, which - due to the fractured water system of the mountains made of red sandstone and shell limestone (without loess cover ) - were rather dry locations. "

The animal fossils uncovered from different layers of the Grafenrain sand pit, which belong to the same warm period as the find layer and are clearly identified, gave the author of a Zeit article in 2007 the impetus for a further columnist view of life :

“Flying squirrels, roe deer, stag, elk and wild boar romped about between spruce, birch and oak. Mole and shrew crawled through the ground. And beavers built their dams in the course of the Urneckar. Brown hares and horses galloped across the open countryside. In theory, nature also offered steaks from forest elephants, woolly rhinos and hippos. It is doubtful whether the Heidelberg man dared to steal such prey. He was sure to run away from the bear, wolf, leopard, saber-toothed tiger and hyena. "

Original recordings from the first description

  • Condition when discovered

  • Condition after cleaning

  • X-rays

  • Top and bottom view

literature

  • Otto Schoetensack: The lower jaw of Homo Heidelbergensis from the sands of Mauer near Heidelberg. A contribution to human paleontology . Verlag von Wilhelm Engelmann, Leipzig 1908 ( full text ).
  • Alfried Wieczorek , Wilfried Rosendahl (Ed.): MenschenZeit. Stories of the dawn of early humans . Philipp von Zabern, Mainz 2003, ISBN 3-8053-3132-0 (catalog for the exhibition of the same name at the Reiss-Engelhorn-Museums in Mannheim).
  • Günther A. Wagner, Hermann Rieder, Ludwig Zöller, Erich Mick (eds.): Homo heidelbergensis. Key find in human history . Konrad Theiss Verlag, Stuttgart 2007, ISBN 978-3-8062-2113-8 .
  • Katerina Harvati : 100 years of Homo heidelbergensis - life and times of a controversial taxon. In: Mitteilungen der Gesellschaft für Urgeschichte 16, 2007, pp. 85–94 PDF .

Web links

Commons : Lower Jaw of Wall  - Collection of images, videos and audio files

Individual evidence

  1. ^ Description of the fossil on the website of the Homo heidelbergensis von Mauer eV association
  2. ↑ Otto Schoetensack : The lower jaw of Homo Heidelbergensis from the sands of Mauer near Heidelberg. A contribution to human paleontology. Leipzig, 1908, published by Wilhelm Engelmann
  3. ^ A b Günther A. Wagner et al .: Radiometric dating of the type-site for Homo heidelbergensis at Mauer, Germany. In: Proceedings of the National Academy of Sciences . Volume 107, No. 46, 2010, pp. 19726-19730 doi: 10.1073 / pnas.1012722107 .
  4. ^ H. Dieter Schreiber u. a .: The fauna of the Mauerer Waldzeit. In: Günther A. Wagner et al. (Ed.): Homo heidelbergensis. Key find in human history. Konrad Theiss Verlag, Stuttgart 2007, p. 146.
  5. ↑ a b Schoetensack, p. 23.
  6. ↑ Schoetensack, p. 23. The removal of the calcareous crusts later led to further damage. a. Tiny splinters of the enamel flake off some teeth . As a result of improper relocation, the two left premolars were also lost during World War II (according to Dietrich Wegner: Der Fund. In: Günther A. Wagner et al., P. 42).
  7. ↑ Schoetensack, p. 24.
  8. ^ Dietrich Wegner: The find. In: Günther A. Wagner et al., P. 19.
  9. ↑ GPIH stands for Geological-Palaeontological Institute Heidelberg.
  10. ^ Dietrich Wegner: The find. In: Günther A. Wagner et al., P. 38. - What Hermann Klaatsch points out in an obituary for Schoetensack: “As is almost generally known in specialist circles, the anatomical treatment of the Heidelberg lower jaw is mainly my work in terms of content and text. (...) The only small clouding of our otherwise ideal friendship alliance was that Schoetensack did not want to see the workforce on the title of his monograph. ”Klaatsch mentions at the same point that the exact description of the teeth was not provided by Schoetensack either , but was developed by Gottlieb Port.
  11. ↑ Schoetensack, pp. 25-26.
  12. ^ Johanna Kontny et al.: Travel diary of a fossil. In: Günther A. Wagner et al., P. 48. - Through intensive chewing, the tooth enamel is gradually removed and the dentin exposed; therefore the extent of this abrasion can be used as a guide for estimating the age.
  13. ^ Günther A. Wagner: 100 years of Homo heidelbergensis from Mauer. In: Günther A. Wagner et al., P. 15.
  14. ↑ Schoetensack, p. 34.
  15. ↑ Schoetensack, p. 40.
  16. ↑ Schoetensack, p. 44.
  17. ↑ a b Schoetensack, p. 4.
  18. ↑ H. Dieter Schreiber among other things: The animal world of the Mauerer Waldzeit. In: Günther A. Wagner et al., P. 129.
  19. ↑ Find of prehistoric men. On: gemeinde-mauer.de , accessed on August 27, 2015. This information apparently relates to layer MIS 15 of the Cromer warm period, which is dated to an age of 621,000 to 568,000 years; cf. to: Günther A. Wagner: Age determination: The long breath of the incarnation. In: Günther A. Wagner et al., P. 224.
  20. ↑ This time span refers to layer MIS 13 of the Cromer warm period, which is dated to an age of 528,000 to 474,000 years.
  21. ^ Johanna Kontny et al.: Travel diary of a fossil. In: Günther A. Wagner et al., P. 44.
  22. ↑ Chris Stringer : Comment: What makes a modern human. In: Nature. Volume 485, No. 7396, 2012, pp. 33-35 (here p. 34), doi: 10.1038 / 485033a
  23. ↑ In 2010, this also included the Geological-Paleontological Institute of the University of Heidelberg, which has kept the lower jaw since 1908 and identified it as Homo erectus heidelbergensis . In the meantime, however, it is also called Homo heidelbergensis in Heidelberg , see the collection of the Institute for Geosciences
  24. ↑ In Asia, descendants of this early settlement may also have survived for some time; the exact assignment of the finds of Homo floresiensis is currently still controversial.
  25. ^ Günther A. Wagner: 100 years of Homo heidelbergensis from Mauer. In: Günther A. Wagner et al., P. 18.
  26. ↑ H. Dieter Schreiber among other things: The animal world of the Mauerer Waldzeit. In: Günther A. Wagner et al., P. 145.
  27. ↑ Urs Willmann: The multiple Adam. In: The time . No. 43 of October 18, 2007, p. 43, full text
This article was added to the list of excellent articles on December 17th, 2012 in this version .