Hello Nature readers,
Today we ponder whether early humans dined on hippos, discover that sea life bounced back surprisingly quickly after a world-altering mass extinction and learn how fingerprints form during fetal development.

How sea life bounced back after extinctions

Marine life bounced back surprisingly quickly after the 'mother of mass extinctions' killed 81% of marine species 251.9 million years ago. More than 1,000 fossils uncovered in southern China show fish, ancient lobsters and prehistoric crab-like creatures existed just a million years after volcanic activity heated the atmosphere and acidified the oceans. It challenges the idea that complex ecosystems took millions of years to recover in a stepwise fashion, from self-sufficient organisms to apex predators.

Who butchered this ancient hippo?

Archaeologists in Kenya have unearthed dozens of stone tools scattered around the butchered bones of ancient hippopotamus-like creatures. The site dates to between 2.6 and 3 million years ago, and pushes back the known start of large-animal butchering by early human relatives by at least 600,000 years. The tools are the earliest known example — by around 700,000 years — of Oldowan tools, which became widespread across Africa and Asia. The tools were found alongside the teeth of an ancient human relative from the genus Paranthropus, raising the possibility that Paranthropus, rather than a member of the modern-human genus Homo, used the tools.

How fingerprints form

The unique whorls, arches and loops of fingerprints are created during fetal development when fine ridges on the skin form and crash into each other. Researchers studying mouse toes and cultured human cells found that waves of ridges emerge from the tip of the finger, the centre of the fingertip, and the crease at the base of the fingertip. When they collide, patterns form through a self-organizing mechanism called a Turing reaction–diffusion system, first proposed by codebreaker Alan Turing in 1952. Similar processes underlie the formation of a zebra's stripes and a cheetah's spots.

Secrets on the surface of antique treasures

Researchers are revealing invisible details of the documents and art held in one of Europe's oldest libraries: the Bodleian Library at the University of Oxford. Using lasers and cameras that can capture tiny differences in surface relief, they have made discoveries such as a nun's scratched doodles in the margins of a 1,300-year-old religious book. And on the earliest known map of the British Isles, dated to the fourteenth century, thousands of pinpricks hint that the layout was copied from an even earlier map.

Futures: Calculating the speed of heartbreak

The calculus of love reveals the cure for dating disappointment (if not killer asteroids) in the latest short story for Nature's Futures series.

Podcast: a space rock's mysterious ring

"This ring should not be there, this ring should not exist," astronomer Bruno Morgado tells the Nature Podcast about what his team discovered around a rock in the outer Solar System, about half the size of Pluto. The chunks of rock, ice and dust that make up the ring are at a distance far outside their supposed stability limit — yet they haven't coalesced into a moon, as would be expected. Whether it's the chunks' bounciness or interactions with another moon that keeps the ring spinning, it is challenging scientists' understanding of planetary rings.