 Akodon spegazzinii was first described in 1897 from Salta Province by Oldfield Thomas on the basis of a collection made in late 1896 or early 1897 by mycologist Carlos Luigi Spegazzini , after whom the species was named . Four years later , Joel Asaph Allen named Akodon tucumanensis from Tucumán Province , comparing it to various species now synonymized under Abrothrix olivaceus . Thomas named an additional species , Akodon alterus , from La Rioja Province in 1919 , and considered it closely related to A. spegazzinii . A fourth species , Akodon leucolimnaeus , was described by Ángel Cabrera from Catamarca Province in 1926 , but after 1932 it was associated with Akodon lactens ( now Necromys lactens ) as a subspecies . 
