A new titanosaur sauropod from the Upper Cretaceous of Neuquén is described, Choconsaurus baileywillisi gen. et sp. nov. The species is represented by a nearly complete series of dorsal vertebrae as well as other parts of the skeleton. The material comes from the locality of Villa El Chocón and stratigraphically from the Huincul Formation, whose age has been estimated as upper Cenomanian. The new taxon presents many autapomorphic features, including the presence of a small notch on the dorsal margin of the posterior articular surface of the cervical centra, accessory articulations lateral to the hyposphene, which are more developed in the anterior dorsal vertebrae, midand posterior dorsal vertebrae with an accessory lamina placed between the posterior centrodiapophyseal and the accessory posterior centrodiapophyseal laminae, and a hyposphene on anterior caudal vertebrae. Phylogenetic analysis recovers Choconsaurus baileywillisi as a non-eutitanosaur titanosaur, taxa that are well represented in the lower Upper Cretaceous of Patagonia. Choconsaurus baileywillisi is, to date, the most complete non-eutitanosaur titanosaur.

In this paper, new remains of the extinct mid-sized testudinid Chelonoidis gringorum (Simpson) from northwestern Chubut (Argentina) are described in detail. The specimens were collected in outcrops of the Collón Curá Formation (middle Miocene) and are represented by postcranial remains, mainly carapaces and plastrons. The taxonomic assignation of these specimens was based on their anatomical comparison with other extant and extinct mid-sized testudinids from South America. Their high intraspecific variation, and the lack of a detailed diagnosis of C. gringorum and detailed descriptions of extinct mid-sized testudinids from South America in general, rendered the study of this group problematic. The geographic distribution of mid-sized testudinids in Argentina during the Miocene shows that there was a displacement towards lower latitudes, which is consistent with the climatic deterioration at the end of the Miocene and in turn had a big impact on Patagonia. Last but not least, the assignation of these specimens to C. gringorum expands the stratigraphic distribution of this species to the middle Miocene because, before, it was only known from the early Miocene.

The shell accumulations produced during the Holocene transgression are recorded along the entire coastal zone of South America and allow for the correlation of different areas. In order to obtain information about taxonomy, taphonomic processes and paleoecology, the mollusk faunas from six sites on the coastal plain of the Cabo Frio area, southeastern Brazil, were analyzed. These analyses were integrated with the sea level and paleoenvironmental changes in the area. The taxonomic analysis identified 42 mollusk species, of which 25 were bivalves, 15 gastropods and two scaphopods. The taphonomic analysis showed two types of assemblages, an autochthonous one, formed in anoxic hypersaline conditions, and an allochthonous one, characterized by a shallow marine environment. The radiocarbon dating of the shells revealed ages between 6260 and 5819 cal. years BP. The cluster analysis showed four faunal associations: Anomalocardia brasiliana, Tivela mactroides, Neritina virginea and Pitar fulminatus. The integration of mollusk associations and taphonomic signatures allowed the authors to distinguish two paleoenvironments: 1) a marine restricted one (6260–5950 cal. yearss BP) dominated by the Anomalocardia brasiliana association, with a low degree of abrasion and fragmentation suggesting a low-energy environment; and 2) a nearshore paleoenvironment (5950–5819 cal. years BP) dominated by the Tivela mactroides, the Neritina virginea/Olivella and the Pitar fulminatus associations, with a high degree of fragmentation and disarticulation denoting a high wave energy environment and marine currents.

Study of carbonate facies from Cretaceous lithostratigraphic units of Peru has led to the identification of calcareous algae, mainly Dasycladales (Apinella hispanica, Salpingoporella ? hasi, Korkyrella sp., Neomeris spp., Trinocladus divnae, and Terquemella spp.), mostly from Cenomanian strata. These algae represent the first records of these taxa on the Pacific margin of South America, in a back-arc setting.

Conifer fossil woods represent 54% of an assemblage of 116 specimens collected from sediments of the Sobral Formation in Seymour (Marambio) Island, Western Antarctica. These woods are anatomically described in detail and assigned to seven fossil-species of the following fossil-genera: Agathoxylon (Araucariaceae), Podocarpoxylon, Phyllocladoxylon, Protophyllocladoxylon (Podocarpaceae), and Cupressinoxylon (Podocarpaceae/Cupressaceae). The conifer wood assemblage reveals that the most common woods are those of Agathoxylon, therefore indicating a relative abundance of the Araucariaceae in the Antarctic Paleocene forests. This abundance of the Araucariaceae woods is locally continued in the overlying Cross Valley Formation (Paleocene). Podocarpaceae woods are found in almost similar proportions to those of the Araucariaceae. Almost the other half of the fossil woods are dicotyledon woods. The proportions of the identified fossil wood taxa are consistent with those of the palynological studies of the same stratigraphic unit.