Elevational range extension of the Puna Mouse, Punomys (Cricetidae), with the first record of the genus from Chile.

This article reports the first record of the Andean sigmodontine rodent genus Punomys in Chile, based on a mummified specimen found at 5,461 meters elevation in the caldera of Volcán Acamarachi, Región de Antofagasta. The specimen is provisionally identified as Punomys lemminus, extending the known geographic range of the genus approximately 700 km southward and establishing a new elevational record for the genus. Morphological and mitochondrial cytochrome b gene analyses confirm the specimen's placement within Punomys but do not conclusively resolve its species-level identity due to unclear distinctions between P. lemminus and P. kofordi. This discovery highlights significant gaps in knowledge about high-elevation Andean mammal diversity and underscores the need for increased biological surveys in remote regions to address these Linnaean and Wallacean shortfalls.