REDESCRIPTION AND DESIGNATION OF A NEOTYPE OF PANOCHTHUS TUBERCULATUS (OWEN) (MAMMALIA, CINGULATA, GLYPTODONTIDAE). We design a neotype for Panochthus tuberculatus (Owen), given that the holotype is missing. A diagnosis and detailed description of the neotype is provided. Glyptodon tuberculatus is the type species of Panochthus Burmeister, one of the genera of giant Pleistocene glyptodonts. P. tuberculatus is recorded in the Bonaerean (late middle Pleistocene) and Lujanian (thus far only for the late Pleistocene lapse of this age) of Argentina, Uruguay, Brazil, Paraguay and, with doubts, Bolivia. Firstly, the species was recognized on the basis of two fragments of dorsal armor; this type material (two syntypes) must be considered as lost, given that it has not been found in the collections of British Museum Natural History, where it was deposited. It is essential that material assigned to P. tuberculatus be made available, to establish the validity of each of the 19 species referred to this genus. The selected material is the complete specimen MLP 16-29, from the Bonaerean of Tapalque (Buenos Aires Province, Argentina). The specimen of P. tuberculatus MLP 16-29 fulfills all the conditions required by the International Code of Zoological Nomenclature and the designed neotype satisfies all the required subsections. The conclusions are: (i) the specimen MLP 16-29, consisting of nearly complete skeleton and armor of a glyptodontid, until now referred to P. morenoi, becomes the neotype of P. tuberculatus; and (ii) consequently, P. morenoi (sensu Ameghino, 1889), is a synonym of P. tuberculatus.