Researchers from Missouri State and the state conservation department tested water from Ozark rivers and streams for environmental DNA, the genetic traces that fish leave behind. Without catching a single fish, they detected species at risk in Missouri, including lake sturgeon and Alabama shad, and a cave-dwelling fish from an underground spring. They expected to find the bleeding shiner, a common Ozark minnow, in every stream, but it appeared only in the southern Ozarks. The missing signal turned out to reflect history: northern bleeding shiners carry a different genetic lineage from ancient hybridisation with another shiner species hundreds of thousands of years ago. Glacial advances during the Pleistocene reshaped northern river networks, while southern drainages stayed relatively isolated and remain rich in unique species. The study shows that water samples can record both current biodiversity and the ancient geology that shaped it.

Hampi is a UNESCO World Heritage Site in Karnataka, India, with more than 1,600 surviving remains spread over 4,100 hectares. It was the capital of the Vijayanagara Empire from 1336 to 1565. Travellers from Persia and Portugal described it as a prosperous, wealthy and grand city with temples, markets and farms along the Tungabhadra River. By 1500 it was estimated to be the world's second-largest city after Beijing, and probably India's richest at the time. In 1565 a coalition of Muslim sultanates defeated the Vijayanagara Empire, its capital was conquered and destroyed, and the city was left in ruins. Hampi remains a religious centre, with the active Virupaksha Temple at its heart.