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Archivo del Autor: Alejandro Pérez-Pérez

001. Evolució Humana: convencions taxonòmiques al voltant d’Homo sapiens

No és un caprici que qualsevol nom taxonómio d’una espècie, com Homo sapiens, s’hagi de escriure en cursiva. L’obra Sistematica Naturae (1735) de Carolus Linnaeus va definir les normes de nomenclatura taxonòmica i classificació científica dels organismes en classes, ordres, gèneres i espècies. Les convencions faciliten la comprensió del procés evolutiu. En la classificació científica, cada espècie rep un nom binomial, on primer se n’indica el gènere i després l’espècie utilitzant els dos termes (gènere i espècie) en llengua llatina, en cursiva o subratllats. Així, els humans pertanyen al gènere Homo i a l’espècie Homo sapiens, que es pot abreujar com H. sapiens o H. sapiens.

Les noves tecnologies dificulten el respecte a aquestes normes bàsiques. Sense anar més lluny, el títol d’aquest blog no permet itàliques ni subratllat, per defecte el meu oridnador inserèix majúscula després d’un punt (H. Sapiens) i la prensa escrita és reticent a escriure el nom especific en cursiva i preferèixen utilitzar cometes: ‘Homo sapiens’. És una pràctica obligada utilitzar itàliques per noms en llatí i subratllat en l’escritura a mà (per raons obvies).

Paleobaboon 2021/24 – UB • MCI

Paleobaboon dental morphology as a proxy for hominin evolution in open terrestrial environments

Glad to share than the Paleobaboon UB project has been proposed for funding during 2021/24 by the AEI-MCI (Spain). Drs. Laura Martínez (Lector, UB), Eduardo Chimenos (TU, UB) & Alejandro Pérez-Pérez (CU, UB) will lead research lines in baboon dental ecology, dental ecology of Hominoidea and modern humans, and hominini dental topography and diet. News on the development of the project will be posted on a regular basis.

Earliest burial of a modern human in Africa

by M. Martinón Torres, Nature May 2021

The origin and evolution of hominin mortuary practices are topics of intense interest and debate. Human burials dated to the Middle Stone Age (MSA) are exceedingly rare in Africa and unknown in East Africa. Here we describe the partial skeleton of a roughly 2.5- to 3.0-year-old child dating to 78.3 ± 4.1 thousand years ago, which was recovered in the MSA layers of Panga ya Saidi (PYS), a cave site in the tropical upland coast of Kenya. Recent excavations have revealed a pit feature containing a child in a flexed position. Geochemical, granulometric and micromorphological analyses of the burial pit content and encasing archaeological layers indicate that the pit was deliberately excavated. Taphonomical evidence, such as the strict articulation or good anatomical association of the skeletal elements and histological evidence of putrefaction, support the in-place decomposition of the fresh body. The presence of little or no displacement of the unstable joints during decomposition points to an interment in a filled space (grave earth), making the PYS finding the oldest known human burial in Africa. The morphological assessment of the partial skeleton is consistent with its assignment to Homo sapiens, although the preservation of some primitive features in the dentition supports increasing evidence for non-gradual assembly of modern traits during the emergence of our species. The PYS burial sheds light on how MSA populations interacted with the dead.

New Hybrid Bone Reveals that Neanderthals and Denisovans Mated

The closest known extinct relatives of modern humans were the thick-browed Neanderthals and the mysterious Denisovans. Now, a bone fragment from a Siberian cave, perhaps from a teenage girl, has revealed the first known hybrid of these groups, a new study concludes. The finding confirms interbreeding that had been only hinted at in earlier genetic studies.

Archaeological excavations have revealed that Neanderthals and Denisovans coexisted in Eurasia, with Neanderthal bones ranging from 200,000 to 40,000 years old unearthed mostly in western Eurasia and Denisovans so far only known from fossils ranging from 200,000 to 30,000 years old found in eastern Eurasia. Prior work unearthed Neanderthal remains in Denisova Cave, raising questions on how closely they interacted.

The Denisovan father of the individual Denisova 11 had at least one Neanderthal ancestor, possibly as far back as 300 to 600 generations before his lifetime. In addition, the teenage girl’s Neanderthal mother was genetically more similar to the Neanderthals of Western Europe than to a different Neanderthal that lived earlier in Denisova Cave. This find suggests that Neanderthals migrated between western and eastern Eurasia for tens of thousands of years.

Viviane Slon, Fabrizio Mafessoni, … Svante Pääbo

Nature (2018) The genome of the offspring of a Neanderthal mother and a Denisovan father.

Homo erectus Were Technologically Conservative, Used Least-Effort Strategies

Archaeological excavations at the Acheulean site of Saffaqah near Dawadmi in central Saudi Arabia have found that Homo erectus, an extinct hominid species that lived between 1.9 million and 143,000 years ago, used ‘least-effort strategies’ for tool making and collecting resources.

C. Shipton et al. 2018. Acheulean technology and landscape use at Dawadmi, central Arabia. PLoS ONE 13 (7): e0200497; doi: 10.1371/journal.pone.0200497

13 million-year-old infant ape skull discovered in the Turkana Basin

The discovery in Kenya of a remarkably complete fossil ape skull reveals what the common ancestor of all living apes and humans may have looked like. The find, announced in the scientific journal Nature on August 10th, belongs to an infant that lived about 13 million years ago. The research was done by an international team led by Isaiah Nengo of the Turkana Basin Institute and De Anza College, USA.

300.000 years old modern humans at Jebel Irhoud

Nature 546, 289–292 (08 June 2017) doi:10.1038/nature22336

The idea that modern people evolved in a single «cradle of humanity» in East Africa some 200,000 years ago is no longer tenable, new research suggests. Fossils of five early humans have been found in North Africa that show Homo sapiens emerged at least 100,000 years earlier than previously recognised. 

Potential hominin affinities of Graecopithecus from the Late Miocene of Europe

  • Fuss J, Spassov N, Begun DR, Böhme M (2017) Potential hominin affinities of Graecopithecus from the Late Miocene of Europe. PLoS ONE 12(5): e0177127. doi:10.1371/journal.pone.0177127.

The split of our own clade from the Panini is undocumented in the fossil record. To fill this gap we investigated the dentognathic morphology of Graecopithecus freybergi from Pyrgos Vassilissis (Greece) and cf. Graecopithecus sp. from Azmaka (Bulgaria), using new μCT and 3D reconstructions of the two known specimens. Pyrgos Vassilissis and Azmaka are currently dated to the early Messinian at 7.175 Ma and 7.24 Ma. Mainly based on its external preservation and the previously vague dating, Graecopithecus is often referred to as nomen dubium. The examination of its previously unknown dental root and pulp canal morphology confirms the taxonomic distinction from the significantly older northern Greek hominine Ouranopithecus. Furthermore, it shows features that point to a possible phylogenetic affinity with hominins. G. freybergi uniquely shares p4 partial root fusion and a possible canine root reduction with this tribe and therefore, provides intriguing evidence of what could be the oldest known hominin.

Naledi fossils dated to 236-335 kya

Homo naledi lived sometime between 335 and 236 thousand years ago. A second chamber in the Rising Star cave system, which contained additional specimens includes a child and the partial skeleton of an adult male with a well-preserved skull that has been named “Neo” – a Sesotho word meaning “a gift”.

  • Homo naledi and Pleistocene hominin evolution in subequatorial Africa. Berger LR, Hawks J, Dirks PH, Elliott M, Roberts EM. Elife. 2017 May 9;6. pii: e24234. doi: 10.7554/eLife.24234.

New Middle Pleistocene hominin cranium from Gruta da Aroeira (Portugal)

The Middle Pleistocene is a crucial time period for studying human evolution in Europe, because it marks the appearance of both fossil hominins ancestral to the later Neandertals and the Acheulean technology. Nevertheless, European sites containing well-dated human remains associated with an Acheulean toolkit remain scarce. The earliest European hominin crania associated with Acheulean handaxes are at the sites of Arago, Atapuerca Sima de los Huesos (SH), and Swanscombe, dating to 400–500 ka (Marine Isotope Stage 11–12). The Atapuerca (SH) fossils and the Swanscombe cranium belong to the Neandertal clade, whereas the Arago hominins have been attributed to an incipient stage of Neandertal evolution, to Homo heidelbergensis, or to a subspecies of Homo erectus. A recently discovered cranium (Aroeira 3) from the Gruta da Aroeira (Almonda karst system, Portugal) dating to 390–436 ka provides important evidence on the earliest European Acheulean-bearing hominins. This cranium is represented by most of the right half of a calvarium (with the exception of the missing occipital bone) and a fragmentary right maxilla preserving part of the nasal floor and two fragmentary molars. The combination of traits in the Aroeira 3 cranium augments the previously documented diversity in the European Middle Pleistocene fossil record.

Daura J, et al (2017) PNAS Early Edition | 1 of 6