The microendemic Aegla expansa (Aeglidae) survives in highly disturbed micro-basins of southern Chile

<i>Aegla expansa</i> was described from an exoskeleton by Jara (1992). The type specimen (holotype) of the species was obtained from the hamlet of La Leonera, approximately six km east of the town of Hualqui in the Biobío region of Chile. Since this find, no further biological information has been generated on this species, and it was even thought to have become Extinct in the Wild. By systematic sampling in the commune (district) of Hualqui, we were able to find populations of <i>A. expansa</i> in many of the district's rivers. In this work, we present the first biological information on the species and assess its phylogenetic position within the genus <i>Aegla</i>.