Scientists sifted through a million years of volcanic ash in a remote cave, and found a forgotten evolutionary world - Futura, le média qui explore le monde

We’re sharing this article early to provide faster access to peer-reviewed, accepted research. It is citable and carries a permanent DOI. This version is subject to further edits and will be replaced automatically by the final Version of Record. All legal disclaimers apply. AbstractNitrogen-fixing cyanobacteria are important sources of bioavailable nitrogen on Earth. Some nitrogen-fixing cyanobacteria are endosymbionts of algae, and recently one of them, UCYN-A2, was shown to be an early-stage organelle (nitroplast) of haptophytes. These biological associations are important models for studying co-evolution and organellogenesis. Endosymbioses between Rhopalodiaceae diatoms and nitrogen-fixing cyanobacteria (spheroid bodies, SBs) are widespread in marine and freshwater ecosystems, but their adaptation and evolution remain unclear. We found that the genomes and metabolic characteristics of marine and freshwater SBs are remarkably similar. Purifying selection pressures dominated SB diversification both within marine and freshwater habitats and across habitat boundaries.

A newly described fungus from Yunnan produces upright structures measuring up to 50 centimeters in total height. DNA and microscopic evidence support a new species, genus and family within the fungal order Xylariales. Its estimated lineage age overlaps the dinosaur extinction, but a connection between that event and its evolution remains hypothetical. Pale, fingerlike structures rising from tree roots in southwestern China have revealed an unexpected giant among fungi. Named Dianjunus rex, the newly described species produces fleshy reproductive structures reaching 50 centimeters in total height. The largest reported specimen weighed 2.2 kilograms, roughly 4.9 pounds. Its size was only the beginning of the surprise. Genetic comparisons and microscopic examinations placed the fungus on a distinct evolutionary branch, supporting a new genus and family. The findings appeared in Frontiers in Fungal Biology. The team included scientists from the Kunming Institute of Botany, Chinese Academy of Sciences, and collaborating institutions. Corresponding author Indunil C. Senanayake works at the institute’s Germplasm Bank of Wild Species.