1. Historically, mutualisms have been considered to be less important than antagonisms in affecting the composition of ecological communities. In plant communities, beneficial microbes may feature as keystone mutualists in structuring community composition. Understanding the direction and magnitude of mutualist effects at the community scale may be critical for making accurate predictions on plant responses to climate change, particularly for mutualists that ameliorate climate-induced stressors. Such mitigation could shift outcomes between mutualist-enhanced species diversity and...

Rhynchocephalian lepidosaurs, though once widespread worldwide, are represented today only by the tuatara (Sphenodon) of New Zealand. After their apparent early Cretaceous extinction in Laurasia, they survived in southern continents. In South America, they are represented by different lineages of Late Cretaceous eupropalinal forms until their disappearance by the Cretaceous/Palaeogene (K/Pg) boundary. We describe here the only unambiguous Palaeogene rhynchocephalian from South America; this new taxon is a younger species of the otherwise Late Cretaceous...