Range extension of the endemic terrestrial isopod Hawaiioscia rapui reveals the dispersal potential of the genus across the South Pacific

Hawaiioscia rapui Taiti & Wynne, 2015 was first described from two caves on Rapa Nui and considered a potential island endemic and disturbance relict (i.e., an organism that becomes a relict species due to anthropogenic activities). As this species was not subterranean-adapted, it may have had an island-wide distribution prior to the arrival of the ancient Polynesians to Rapa Nui. We report new records for Hawaiioscia rapui beyond its type locality. These findings extend this animal's range to the closest neighboring island, Motu Motiro Hiva (MMH), 414 km east by northeast of Rapa Nui. We also report information on this animal's natural history, discuss potential dispersal mechanisms, identify research needs, and provide strategies for management. Our discovery further underscores that MMH likely harbors a unique and highly adapted halophilic endemic arthropod community. Conservation policies will be required to prevent alien species introductions; additionally, an inventory and monitoring program should be considered to develop science-based strategies to manage the island's ecosystem and species most effectively.