 "Alnashetri" was first described and named by Peter J. Makovicky, , and Federico A. Gianechini in 2012 and the type species is "Alnashetri cerropoliciensis".The generic name is derived from the Günün-a-kunna dialect of the Tehuelchan language, meaning "slender thighs" in reference to long and slender hind limbs of the holotype.The specific name "cerropoliciensis" honors the nearby small village of Cerro Policía for the generous assistance from its residents in fieldwork efforts at La Buitrera locality since its discovery in 1999.