Abstract In the late Pleistocene, Panochthus was the most diverse genus of glyptodontids with five species: P. jaguaribensis, endemic to the intertropical region of Brazil, P. hipsilis from Bolivia, P. greslebini from Brazil and Argentina, P. tuberculatus from Uruguay and Argentina and P. frenzelianus, probably from the Pampean region, Argentina. In this paper we describe the robust caudal tube of a new species, Panochthus florensis n. sp., that inhabited the center of the Pampean region of Argentina at the end of the Pleistocene. The reduction in the number of central figures, a single apical figure, the absence of an apexian figure, and the lack of figures between the first pair of dorsal figures allow a rapid differentiation from the already known species. The striking diversity of Panochthus contrasting with that of other late Pleistocene glyptodontids, lead us to propose hypotheses for explaining this fact.