Evolution

Blogs about evolution

An illustration of the musculoskeletal system of the African coelacanth (Latimeria chalumnae)

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An article published in the journal “Science Advances” reports the results of a thorough examination of the cranial musculature of the African coelacanth (Latimeria chalumnae), a so-called living fossil because it has changed very little over tens of millions of years. Professor Aléssio Datovo of the University of São Paulo, Brazil, and G. David Johnson of the Smithsonian Institution dissected two specimens of this fish to gain new insights into the evolution of gnathostomes, a chordate infraphylum that includes jawed vertebrates. As a result, the two researchers discovered that much anatomical information about coelacanths was incorrect.

The skull cataloged as Kabwe 1 attributed to a Homo heidelbergensis

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An article published in the journal “Nature Genetics” reports the results of a sophisticated genetic research that concludes that the species Homo sapiens is the result of the crossbreeding between two populations belonging to different species of hominins. Trevor Cousins, Aylwyn Scally, and Richard Durbin of the British University of Cambridge developed a genetic analysis software called cobraa to create models of ancient human populations splitting apart and merging back. The application of cobraa to the genetic data obtained from modern humans from all over the world indicates a split between two populations dating back to about 1.5 million years ago to a crossbreeding between their descendants about 300,000 years ago. The two species could be Homo erectus and Homo heidelbergensis but for now, these are hypotheses.

Navaornis hestiae skeleton (Photo courtesy Stephanie Abramowicz)

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An article published in the journal “Nature” reports the identification of a species of primitive birds that lived about 80 million years ago, in the Cretaceous period, in today’s Brazil. A team of researchers examined a very well-preserved fossil skeleton and named the species Navaornis hestiae, attributing it to the group of Enantiornithes. A thorough examination was possible by subjecting the skeleton to a CT scan that allowed them to create a 3D reconstruction. The characteristics of the brain of this primitive bird offer new information on the evolution of bird brain.

Palaeopycnogonides gracilis fossil (Photo courtesy Dr Romain Sabroux)

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An article published in the journal “Papers in Palaeontology” reports the results of an examination of rare fossils of so-called sea spiders dating back to about 160 million years ago, during the Jurassic period. A team of researchers examined these fossils of marine arthropods which technically belong to the class of Pycnogonids (Pycnogonida). Fossils of these arthropods are rare and among them are some of the so-called fauna of La Voulte-sur-Rhône, a deposit in southwestern France known for its excellent conservation and abundance of fossils. This study led to the identification of three species of sea spiders which were named Palaeopycnogonides gracilis, Colossopantopodus boissinensis, and Palaeoendeis elmii. Their resemblance to the current species of Pycnogonids leads to the conclusion that their diversification began right in the Jurassic.

The structure of the various groups of archaea resulting from this study with eukaryotes as part of this taxonomic domain

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An article published in the journal “Nature” reports the results of a genetic study on the archaea Asgard that expands the genetic diversity of this group of microorganisms and concludes that the taxonomic order Hodarchaeales is the one most closely related to eukaryotes, the organisms that make up all forms of multicellular life on Earth. A team of researchers conducted a genetic analysis of Asgard archaea from samples collected at 11 locations around the world in a genomic research using state-of-the-art analysis techniques. The conclusion is that eukaryotes constitute a group within the Asgard archaea, from which they may have directly evolved.