Blogs about evolution

Palaeopycnogonides gracilis fossil (Photo courtesy Dr Romain Sabroux)

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

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.

A schematic of the various evolutionary patterns of Homo sapiens including also an interbreeding with Neanderthals

An article published in the journal “Nature” reports a study that relaunches the idea that the Homo sapiens species emerged not from a single population that had e linear evolution but from different groups of genetically similar hominins that diversified and then interbred again. A team of researchers led by Brenna Henn of the University of California-Davis, USA, and Simon Gravel of McGill University in Montreal, Canada, conducted a genetic analysis and a comparison with early Homo sapiens fossils to try and locate the origin of modern humans. The researchers tested different evolutionary and migratory models and the one that best matches the data points to ramifications of African populations that subsequently interbred again until they merged.

Photos of Rotadiscus grandis fossils and their interpretive drawings

An article published in the journal “Current Biology” reports a study on exceptionally preserved Rotadiscus grandis fossils. A team of researchers led by Dr Imran Rahman of the Natural History Museum in London offered many new insights into these animals dating back to the Lower Cambrian period, about 518 million years ago. Previous studies had left a number of questions about their classification and lifestyle. The new study assigns them to the large Ambulacraria group, which includes the Echinoderms and Hemicordata phyla and is part of the superphylum Deuterostomia together with the phylum of Chordates. If this classification is correct, it indicates that certain characteristics of later animal species emerged independently several times.

An Asgard archaeon of the proposed species Lokiarchaeum ossiferum

An article published in the journal “Nature” reports a study on archaea that belong to the proposed superphylum called Asgard and in particular on their characteristics that make them a possible evolutionary missing link with eukaryotes. A team of researchers formed by the collaboration of the working groups of Christa Schleper of the Austrian University of Vienna and Martin Pilhofer of ETH Zurich was successful in cultivating a species belonging to this group of microorganisms to study them in the laboratory. This allowed conducting thorough examinations of their cellular structures such as the extensive cytoskeleton.