Aegla

Aegla is a genus of freshwater decapod crustaceans in the family Aeglidae, endemic to southern South America. Species inhabit streams and small rivers in Chile, Argentina, Uruguay, and southern Brazil. The genus comprises numerous described species, with ongoing taxonomic revisions and discoveries of cryptic diversity through molecular studies.

Description: Members are generally small to medium-sized crustaceans with a flattened body adapted to life under rocks in shallow, fast-flowing waters. They have a broad carapace, five pairs of walking legs, and chelae on the first pair in males. The abdomen is short; eyes are on stalks. Females brood eggs on pleopods beneath the abdomen; juveniles resemble adults.

Distribution and habitat: Aegla species are largely endemic to temperate freshwater systems of southern South America, including Pacific drainages in Chile and western Argentina and Atlantic basins in eastern Argentina, Uruguay, and southern Brazil. They prefer cool, well-oxygenated waters and are commonly found under stones or within leaf litter.

Ecology and behavior: They are omnivorous detritivores feeding on algae, decomposing plant material, and small invertebrates. Primarily nocturnal, they shelter during the day and show territorial tendencies on rocky substrates. Reproduction is sexual, with females carrying fertilized eggs on pleopods until hatching.

Taxonomy and significance: Aegla is the type genus of Aeglidae. The group has a long evolutionary history and high species diversity across its range; molecular analyses have revealed cryptic lineages and clarified relationships within the family.

Conservation: Many Aegla species have restricted ranges and are threatened by habitat modification, pollution, and altered stream flow. Protecting freshwater habitats and water quality is important for maintaining populations.