The Artazu VII site (Arrasate, northern Iberian Peninsula) is a fossiliferous deposit that was discovered unsystematically at the Kobate Quarry in 2012. During the following year, all the vertebrate remains attributed to the upper Pleistocene (~ 93 ka) were recovered in an emergency excavation project. Here, we describe, for the first time, the small vertebrate assemblage (amphibians, reptiles, and small mammals) recovered from the site, as well as the environmental and climatic results estimated from the paleoecological affinities of the studied taxa. More than 50,000 microvertebrate elements were recovered, comprising 24 taxa of which seven belong to the Order Rodentia; five, to the Order Eulipotyphla; one, to the Order Chiroptera; seven, to the Order Anura; and four, to the Order Squamata. Considering the environmental attributions and the relative abundance of each taxon, the paleoenvironmental and paleoclimatic conditions were reconstructed and the sequence was divided into three phases. Although woodland mass is present in the whole sequence, expansion and regression changes can be observed. Thus, the stratigraphic sequence begins with a landscape with open spaces. Higher up the stratigraphic column, woodland expands and reaches its maximum development in the second phase. Finally, the woodland environment declines and reaches similar values to those of the initial situation. These forestry biotopes were related to temperate and humid conditions comparable to those of the modern landscape. It was also concluded that a watercourse existed near the site.

The “Irenean” is a controversial unit traditionally employed to embrace fossil vertebrates and bearing-sediments of late Neogene—roughly Pliocene—age in southern Buenos Aires Province, Argentina. Although originally intended as an intermediate unit between Montehermosan and Chapadmalalan faunas, almost a century after its description, the “Irenenean” is still poorly known. Based on fieldwork by our team during the last 25 years in its type area, the Quequén Salado River, we revisit the basic aspects of the “Irenean”. We describe the main paleontological localities and the correlations suggested by fossils and sediments and also discuss the chronology of these deposits. We conclude that the “Irenean” is a complex unit composed of at least two fossilife rous assemblages. An older assemblage is found in sediments exposed in localities downstream of the mouth of Indio Rico; a younger assemblage is contained in outcrops upstream of the mentioned point and includes the classic site of Cascada Grande. The older assemblage includes the cingulate Macrochorobates sp., the caenolestid Pliolestes tripotamicus, the tardigrade Proscelidodon cf. P. patrius and the rodent Xenodontomys ellipticus, and points to a sensu lato Huayquerian Stage/Age. The younger assemblage is typified by several taxa, including the rodents Actenomys sp. and Eumysops laeviplicatus, the argyrolagid Argyrolagus sp., the didelphid Hyperdidelphys inexpectata, the macraucheniid Promacrauchenia cf. P. chapadmalense, and the cingulate Ringueletia simpsoni, suggesting a Montehermosan Stage/Age.

Melanosuchus niger Spix is distributed throughout the Amazon River basin today. The extinct Melanosuchus fisheri Medina from the late Miocene of Venezuela was erected based on two almost complete, but heavily deformed skulls (the holotype MCNC 243 and the referred specimen MCZ 4336), which show morphological differences from each other. The comparison indicates that only the holotype can be referred to Melanosuchus Gray. We propose MCZ 4336 is a representative of the caimanine Globidentosuchus brachyrostris Scheyer, Aguilera, Delfino, Fortier, Carlini, Sánchez, Carrillo-Briceño, Quiroz and Sãnchez-Villagra. Although the taxonomy of M. fisheri is taken into question herein, the classification of the holotype still sustains the hypothesis that the genus is registered in South America since the late Miocene.

The Alta Vista Formation represents one of the first Late Cretaceous marine deposits accumulated during the foreland stage of the Austral Basin, Patagonia. All the analyzed samples contain dinoflagellate cysts denoting marine conditions throughout the unit and, despite the extremely poor preservation of the assemblages, diagnostic species were identified. The age of the Alta Vista Formation was assigned between the late Santonian and the late Campanian based on the invertebrate remains. Nevertheless, the age is still debatable and a detailed biostratigraphy has not been proposed for the unit so far. As in other Late Cretaceous Southern Hemisphere middle to high latitude successions, the dinoflagellate cysts from the Alta Vista Formation are useful for biostratigraphic interpretations. The co-occurrence of Odontochitina porifera, Palaeohystrichophora infusorioides, Nelsoniella aceras, Nelsoniella tuberculata and Xenikoon australis is consistent with a Campanian age, which in accordance with the age indicated by the invertebrates recorded in other localities in which the unit crops out. The occurrence of Xenikoon australis and Nelsoniella tuberculata constrains the age of the unit to the early—middle Campanian. Since the basal levels were not identified in the studied sections, the age herein suggested corresponds to the upper part of the Alta Vista Formation.