Mauer 1

The lower jaw of the wall is so far the oldest fossil of the genus Homo, which was recovered in Germany. It was founded in 1907 around ten kilometers southeast of Heidelberg discovered in a sand pit the community wall. The lower jaw of Wall is the type specimen of the species Homo heidelbergensis. From European researchers the Fund is also referred to as Homo erectus heidelbergensis and thus provided as a subspecies of Homo erectus. The age of the mandible was first absolutely dated in 2010 and should therefore be 609,000 ± 40,000 years. Previously an age of either 600,000 or 500,000 years was referred to as probably in the medical literature relative dating methods.

Fund history

On October 21, 1907 in the Bausandgrube in Won Graf Rain the community put the sand graves Daniel Hartmann ( 1854-1952 ) wall, 24.63 meters below the former ground surface, with his shovel a mandibular free, in which he recognized the remains of a man. This was possible for him because of Heidelberger private scholar Otto Schoetensack (1850-1912) had stopped the workers of the sand pit for 20 years to look for fossils after 1887 in this sand pit of the well-preserved skull of a forest elephants had come to light. Schoetensack the workers had also taught the appearance of human bones on the basis of recent examples and the sand pit monitored frequently " traces of man."

The lower jaw was thrown when shoveling sand through the air and not discovered until after he was already broken in the middle into two parts. On the left side at the same time bursting from a piece that was later not found. It also adhered " and next to the corner and molars of the lower jaw thick solidified crusts of rather coarse sand, a characteristic of originating from the Mauer sands fossils. The cementing is done by carbonate of lime. On the left half of the jaw also was on the premolars and first two molars, fixed to the sands, a six inches long and about four inches wide boulders of limestone, probably limestone. "

Schoetensack was notified of the find of the tenants of the sand pit. He examined reference and mandible and presented the results of his studies in the autumn of the following year in a monograph before, to 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 Rösch ( 1838-1925 ) leave the fund as a donation to the University of Heidelberg; in their geological- palaeontological Institute of the lower jaw is still preserved. He is now " the most valuable object in the natural history collections of the University of Heidelberg ." On the right inside of the lower jaw, the collection number of the fossil is in the region of the joint with black lettering in capitals indicated: " GPIH 1" and including " WALL 1".

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

Fund Description

The in the first description of the lower jaw of Mauer by Otto Schoetensack presented in 1908 anatomical analysis was based mainly on the expertise of the Wroclaw university teacher Hermann Klaatsch; but this was only hinted at in a brief thanksgiving in their preface.

In his first description Schoetensack wrote that the " nature of our object " to urge " at first glance to" because " a certain disproportion between the jaw and the teeth " is unmistakable: " The teeth are too small for the bone. The available space would allow them a very different unfolding " And further on the find.:

Characteristic of the lower jaw are therefore on the one hand the lack of chin, on the other hand, the considerable size of the lower jaw bone, would have on the behind the wisdom tooth yet a fourth molar tooth can find space. Since the third molars ( or wisdom teeth ) are present, but the dentin is exposed only in a few places, the age is estimated at death at about 20 to 30 years.

Schoetensack concluded from the similarity of the dentition on the relationship to the people of today (Homo sapiens) and presented the mandible, therefore, to the genus Homo - a view that is also today still represent unanimously by the paleoanthropologists. From the fact that the lower jaw - in contrast to modern humans - including missing the chin, Schoetensack derived the authority to define a new style with the Style epithet heidelbergensis. By the subtitle of his first description - " A Contribution to the paleontology of the people " - referring Schoetensack both on the part of Darwinism " a clear position in the great conflict of his time on the origin of man: that man has evolved from the animal stage and not was thanks to already as finished being a biblical act of creation. "

The exact position of the mandible of wall in the chain of ancestors of modern man is Schoetensack expressed only cautious: he wrote restrained in his study that "it seems possible that Homo heidelbergensis ancestral series of European man " belong and - after extensive comparisons with other European Fossils - elsewhere equally vague: "We must therefore refer to the mandible of Homo heidelbergensis as präneandertaloid. " classification of the lower jaw of wall in the time before the Neanderthals proved correct.

Wrong was Schoetensack - like many of his colleagues around the turn of the 20th century - but with the estimation of the kinship proximity of the lower jaw of wall with the great apes ( hominids ): " The mandible of Homo heidelbergensis reveals the original state which of the common ancestor humanity and the great apes approached " 1924 the hitherto oldest fossil was in South Africa today discovered from the mold among the hominids -. , the Taung Child - the roughly two million years older than the lower jaw of Mauer and despite his advanced age, not to the common is based on humans and apes.

Dating

Otto Schoetensack left the site on the bottom of the sand pit marked with a commemorative stone on which a horizontal line represented the Fund level. Whether his wish was fulfilled, this stone may stay well, although the sand pit will one day filled again, is unknown; actually was that part of the pit, in which the lower jaw became apparent, filled in the 1930s with overburden, then renatured as arable land and declared a nature reserve in 1982; the reference is therefore no longer available for research. An absolute dating of the site with the help of modern scientific method was therefore used to be impossible. Alternatively, have repeatedly tried to limit using stratigraphic methods, the age of the fossil, at least.

The only ten centimeters thick layer Fund was already "slightly cemented gravel layer by carbonate of lime, with very thin layers of Latvians, the weak roars with HCl " of Schoetensack as has been described. Above and below the find layer of sand embedded in various definable layers and other material that had been deposited on the edge of a former Neckar- arc over the course of millennia. In the preface to his study states: " The age of these sands is commonly indicated by the fact encountered mammal remains as altdiluvial; but some species it can also be represented significant relationships among the youngest sections of the Tertiary, the Pliocene, recognize. " After today's dating this information would mean a lower age limit of around 780,000 years and a top of several million years.

Although Schoetensack detail numerous fossil species described, whose remains were found in the sand pit, he obviously has not tried to actually search what he calls the " layer 4" designated Fund layer of the mandible fossils. Instead, he carries in his book page by page finds, whose assignment to particular Fund layers it does not seem possible. A relative date based on accompanying findings is not possible on the basis of pre- established by him material.

In 2007 the 100th anniversary of the discovery published scientific Festschrift was therefore complained that " still existed no satisfactory exact data for the geological age determination of the lower jaw of Homo heidelbergensis. " Using small fossils from the wall could since 1995, after all, the age of the mason sands are increasingly better define; Moreover, an attempt was made to perform an absolute dating in yet accessible, adjacent sand pits. To date, however, the researchers could not agree on which, with the discovery layer from the pit Graf Rain are identical of several possible layers that belong to the Cromer interglacial period, respectively. So it happens that the church wall on its website the Fund an age " of more than 600,000 years," attributes, however, the memorial stone called an age of 500,000 years. As secured for the age of the " layer 4" currently has a range 474000-621000 years, with the fossil either the lower section stems ( 500,000 ) or the top (around 600,000 ).

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

Relationship with modern humans

The lower jaw of Wall is the type specimen for the species Homo heidelbergensis. " The anatomical relationships are clearly more primitive than in Neanderthals, but in harmoniously rounded arch and complete row of teeth already, typically human. '" From this circumstance - on the one hand the delineation of time later Neanderthals, on the other hand to the older, known as Homo erectus fossils - is today derived even by many researchers permission to assign the lower jaw of an independent Chrono species: for example, is Homo heidelbergensis Chris Stringer that between on the one hand, Homo erectus, on the other hand, Neanderthals and Homo sapiens and is from this point of view the last common ancestor of Neanderthals and anatomically modern humans.

Other researchers hold contrary to the phylogenetic development in Africa and Europe sliding of Homo erectus about the discoveries made ​​to Homo heidelbergensis was the Neanderthals; each demarcation is arbitrary, which is why these scholars waive the designation Homo heidelbergensis. Therefore assign also the lower jaw of the wall as a local ( European ) late form of Homo erectus.

There is agreement, however, in paleoanthropology about the fact that the lower jaw of the wall does not belong to the immediate ancestors of modern man series. He is regarded rather as a descendant of an early colonization of Europe and Asia (depending on the terminology by Homo erectus or Homo heidelbergensis ), the oldest fossils outside Africa are around 1.8 million years old. Last descendant of the first settlement in Europe were the Neanderthals, who became extinct about 30,000 years ago. Only in a second wave spread of the genus Homo invaded 40000-30000 years before members of the species Homo sapiens to Europe, to whose descendants today's people count.

Habitat

However uncertain as to the exact dating of the lower jaw of Mauer, until recently, was so uncertain is still the assignment of other fossils whose references layer. Such accompanying fossils are the only direct evidence to reconstruct the habitat of a find can. Only in 1991 were drilled in the disused sand pit Graf Rain two research boreholes. In addition, several dozen cubic meters of sand were sieved since 1995, in search of small fossils, could provide information about the time being settled there ways. However, the actually discovered mice teeth were not suitable for a more precise dating of the Fund layer since these mice lived across anatomically virtually unchanged over a too long period of time. Based on palynological findings in similar vegetation areas of habitat, during the Cromer interglacial period at least be described as " through wetland forests in the river valleys, forests on the slopes and open forests on the heights, the result of the joint water system of the mountains of sandstone and limestone (without Lössbedeckung ) rather dry locations were. "

The exposed from different layers of sand pit Graf Rain animal fossils, belonging to the same interglacial epoch as the Fund layer and are clearly identified, gave the author a Time article in 2007 kick-off to another feuilletonistic life picture:

Original recordings from the first description

Condition after cleaning

Radiographs

Top and bottom view