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

## TL;DR

This paper reports the rediscovery of a rare freshwater crab species in Chile and provides its first biological data and evolutionary placement.

## Contribution

The study presents the first biological information and phylogenetic analysis for Aegla expansa, a previously little-known and presumed extinct species.

## Key findings

- Aegla expansa populations were found in multiple rivers within the Hualqui district.
- The study provides the first biological data on Aegla expansa, including its current distribution and phylogenetic position within the genus Aegla.

## Abstract

Aegla
expansa 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 A.
expansa 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 Aegla.