Once a favored food of grazing dinosaurs, an ancient lineage of plants called cycads helped sustain these and other prehistoric animals during the Mesozoic Era, starting 252 million years ago, by being plentiful in the forest understory. Today, just a few species of the palm-like plants survive in tropical and subtropical habitats.

Like their lumbering grazers, most cycads have gone extinct. Their disappearance from their prior habitats began during the late Mesozoic and continued into the early Cenozoic Era, punctuated by the cataclysmic asteroid impact and volcanic activity that mark the K-Pg boundary 66 million years ago. However, unlike the dinosaurs, somehow a few groups of cycads survived to the present.

A study, "Nitrogen Isotopes Reveal Independent Origins of N2-Fixing Symbiosis in Extant Cycad Lineages," appearing Nov. 16 in the journal Nature Ecology & Evolution has concluded that the cycad species that survived relied on symbiotic bacteria in their roots, which provide them with nitrogen to grow. Just like modern legumes and other plants that use nitrogen fixation, these cycads trade their sugars with bacteria in their roots in exchange for nitrogen plucked from the atmosphere.

An extraordinary insect preserved in amber is opening our ears to a world of communication beyond our hearing. New research on an extinct katydid in the Natural History Museum's collection reveals that katydids have been using ultrasounds for millions of years to try and avoid predators hearing them.

The song and hearing range of the cricket-like insect has been discovered tens of millions of years after its death.

After being trapped in amber for 44 million years, new scans of Eomortoniellus handlirschi have allowed scientists to reconstruct the katydid's mating call. It reveals the earliest known animal to communicate at frequencies far beyond the range of human hearing.

While not quite as high as some living katydids, its call's pitch would have been above the hearing of most mammals. Only a select group of mammals, including the first bats, were tuning into its call, as part of the opening salvos of an evolutionary arms race which continues today.