Aroeira 3 skull

from Wikipedia, the free encyclopedia

The Aroeira 3 skull ( English Aroeira 3 cranium ) is a roughly 400,000 year old hominine skull from the Middle Pleistocene . Hominin fossils from this era are now mostly referred to as Homo heidelbergensis , a Chronospecies that stands at the transition between Homo erectus and early Neanderthals . The Paleolithic Acheulean culture , to which this and other finds in the Gruta da Aroeira in Portugal can be assigned, is characterized by the production ofStone tools , namely the hand ax , and the use of fire. The skull was damaged by a jackhammer during the excavation work in the hard conglomerate rock in 2014 and restored in the following two years. It was only in 2017 that the description of the skull was published in the journal Proceedings of the Academy of Sciences of the United States of America . The international press then reported on the find.

features

The skull find Aroeira 3 shows some features that have already been discovered in the skulls found in a similar period in Europe, but their combination is unique. The bulges above the eyes are continuous, as in the skull fragments of Homo erectus bilzingslebensis unearthed at the Bilzingsleben site . The mastoid process of the temporal bone is short as in Homo steinheimensis from the gravel pit near Steinheim an der Murr . The large, triangular bone cone on the temporal bone near the auditory canal is also present in skull no. 5 from the Sima de los Huesos site , the world's best preserved skull of a Homo heidelbergensis . However, the Aroeira 3 skull differs from this and from Homo steinheimensis in the lack of essential features that also occur in the early Neanderthals.

Location

The source of the Rio Almonda , a tributary of the Tejo , lies in the karst of the central limestone massif of the Portuguese Estremadura . The river forms an approximately 40 kilometer long incision in the limestone massif with steep banks up to 70 meters high. On these steep banks there are various entrances to caves and cave systems, some of which have collapsed or filled. Some of these caves have been excavated and explored. They offer access to the history of human development during the Pleistocene and the cultural history of the Paleolithic . Some cave systems were used during the early Paleolithic , such as the Entrada Superior, the Entrada do Vale da Serra and the Gruta da Aroeira. The Middle Paleolithic is represented in the Gruta da Oliveira . Upper Paleolithic developments of Solutréens and Magdalenian can be found in the Galeria da Cisterna and the Lapa dos Coelhos.

The caves have been systematically explored since 1978, the excavation work in the Gruta da Aroeira began in 1998 and continued in the first phase until 2002. In addition to two early human teeth (a canine tooth and a molar, known under the names Aroeira 1 and Aroeira 2), hand axes from the Acheuléen that were worked on both sides were also found. The second phase of the excavation lasted from 2013 to 2015, with the well-preserved Aroeira 3 skull being found near a stalagmite in 2014 . Because of the hardness of the sediment in which it was embedded, it was damaged during the rescue and had to be recovered in parts and subsequently reconstructed.

Age determination

Various methods could be used for dating, including the uranium-thorium examination . Using this method, the age of the outer layer of the stalagmite, in the vicinity of which the skull was found, could be dated to 406,000 years within a fluctuation range of 30,000 years upwards or downwards. So this is the upper limit of the age of the fossil, as the stalagmite was later buried by debris and mud and stopped growing. Calcite crusts on the skull itself could be dated to an age of 390,000 years (± 14,000 years). Following these measurements, the skull is between 390,000 and 436,000 years old.

Individual evidence

  1. ↑ a b c Joan Daura, Montserrat Sanz, Juan Luis Arsuaga, Dirk L. Hoffmannd, Rolf M. Quam, María Cruz Ortega, Elena Santos, Sandra Gómez, Angel Rubio, Lucía Villaescusa, Pedro Souto, João Mauricio, Filipa Rodrigues, Artur Ferreira, Paulo Godinho, Erik Trinkaus and João Zilhão : New Middle Pleistocene hominin cranium from Gruta da Aroeira (Portugal). Proceedings of the Academy of Sciences of the United States of America, March 2017 ( PDF )
  2. ↑ Der Urmensch from Portugal , article in the Hamburger Abendblatt from March 16, 2017, accessed on March 22, 2017
  3. ↑ Crânio de 400 mil anos é o fóssil humano mais antigo descoberto em Portugal (German: "A 400,000 year old skull is the oldest human fossil discovered in Portugal"), in the Portuguese newspaper Público of March 13, 2017, accessed on March 22, 2017. March 2017
  4. ^ Roberto Sáez: Aroeira 3: The westernmost Middle Pleistocene cranium of Europe. Nutcracker Man, outreaching the human evolution research, March 13, 2017, accessed March 15, 2017
  5. ↑ João Zilhão, Diego E. Angelucci, Joan Daura, Marianne Deschamps, Dirk L. Hoffmann, Henrique Matias, Mariana Nabais, Montserrat Sanz: Almonda karst system (Torres Novas, Portugal): a window into half a million years of long-term change in climate, settlement, subsistence, technology and cult.  ( Page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. Proceedings of the European Society for the study of Human Evolution, 5, 2016, p. 253.@1@ 2Template: dead link / repositorio.ul.pt  

Web links