VERTEBRATE TRACKS OF THE RÍO NEGRO PROVINCE, PATAGONIA, ARGENTINA: STRATIGRAPHY, PALAEOBIOLOGY AND ENVIRONMENTAL CONTEXTS

To date, the tetrapod ichnological record in the Río Negro province, Argentina, is knownfrom six areas from the Permo-Triassicto Neogene. Tetrapod tracks have been identified indifferent palaeoenvironments and geodinamic contexts. The oldest track record is representedby the therapsid tracks from the Los Menucos Group. A prevailing Dicynodontipus andDicynodontipus-like footprints, Lopingian-Early Triassic in age, comes from the Tscherig andPuesto Vera localities, while Pentasauropus tracks, presumably Late Triassic in age,wererecognized in the Yancaqueo locality. A tridactyl track-bearing level, still unpublished(related to El Refugio Formation, Middle-Upper Triassic), has been found in the Puesto Pradofarm, in the Arroyo de la Ventana area. Some tracks classified as cf. Anomoepus andundetermined tridactyl tracks have been identified in the Perdomo farm(Marifil VolcanicComplex). The Late Cretaceous (Cenomanian) record is represented by the ornithopod,sauropod and theropod tracks from the Candeleros Formation (Ezequiel Ramos Mexía area). Moreover, cf. Iguanodontipodidae, sauropod and avian tracks from the Anacleto and AllenFormations characterise the latest Cretaceous (Campanian-early Maastrichtian) of the PasoCórdoba area.Avian tracks were also reportedfromthe Ingeniero Jacobacci area, from theAngostura Colorada Formation (upper Campanian-lower Maastrichtian), andfrom the RíoNegro Formation (upper Miocene-lower Pliocene) along the shoreline of the province. In thisarea, tens of tracksites and several ichnotaxa have been studied. In regard ofpalaeoenvironments, ichnosites are constrained to three main sedimentary settings: fluviovolcaniclastic,fluvial/fluvial-aeolian and shallow marine systems. Finally, a brief discussionabout palaeobiology and heritage issues is provided.