Critically Endangered Stonefly rediscovered

After a 22-year absence the critically endangered stonefly Isogenus nubecula has been rediscovered in the River Dee in North Wales by John Davy-Bowker of the Freshwater Biological Association. Part of an ancient group of insects that have changed little since the Permian period 250 million years ago, stoneflies are typically found in cool, well oxygenated waters and are particularly susceptible to pollution. Generally taking a year to mature, they grow as nymphs clinging under stones in fast flowing areas of streams and rivers, in the spring emerging into winged adults which mate and lay the next generation of eggs.

Source: Critically Endangered Stonefly (Isogenus nubecula) Rediscovered after 22 Year Absence | Freshwater Biological Association