We re-describe the holotype and referred specimen of Prosqualodon australis, from the early Miocene of Gaiman Formation (Chubut Province, Argentina), and analyse its phylogenetic position. Our study shows that this taxon is presently represented by an adult and a juvenile individuals and we provide the first diagnosis of the species based on the morphology of the anterior projection of the antorbital process along with plesiomorphic dental features (such as well-marked heterodont teeth, with posterior double rooted teeth in the maxilla, large, lateromedially compressed teeth with long crowns and denticulated enamel). The total body length of P. australis is estimated to be 2 m in the juvenile and 3 m in the adult specimen. We included for the first time this species in a phylogenetic analysis as an operational taxonomic unit itself, recovering P. australis as a stem-odontocete and Prosqualodon as a paraphyletic genus.

A 20 m-thick interval of the Puerto Madryn Formation was the subject of a multiproxy study, including sedimentological and stratigraphical observations as well as marine-derived amorphous organic matter, phytoclast, palynomorphs and calcareous nannofossils assessments. Three palynofacies were defined based on qualitative and quantitative analysis of the palynological organic matter that contributed to the palaeoenvironment inferences. Based on their sedimentology, palynology and calcareous nannofossils, the section was divided into four intervals: Interval 1 accumulated in relatively stable, warm water conditions, without salinity fluctuations, in an inner shelf; Intervals 2 and 3 show a marked upward fining trend and a progressive change towards a phytoclast-dominated palynofacies; Interval 4, which represents a reinstauration of normal marine conditions with a regressive trend. The accumulation of the finest-grained deposits on the shelf corresponds to the most continental signature of the succession which seems to contradict the classic grain-size stratigraphic trends for shallow marine sedimentary successions. We interpret this deposit as the result of the progressive increase of fluvial, mud-laden freshwater input into the depositional system produced by switching of deltaic channels processes. The dinocyst assemblages reflect overall warm-water conditions. Nevertheless, the presence of cool-water indicator species in some levels suggests the influence of Antarctic cold-waters. The diagnostic dinocyst and nannofossil taxa support the age of the studied interval as Serravalian–Tortonian.

The coral patch reef of the La Manga Formation at Bardas Blancas (Mendoza Province) is a good example of this kind of structure for the Upper Jurassic (Oxfordian) of the Neuquén Basin. In previous reports, four different genera of corals were identified: Actinastrea, Australoseris, Garateastrea, and Thamnasteria. A new systematic revision of the previously studied specimens and new material, lead to the rejection of the assignments to Garateastrea, Actinastrea, and Thamnasteria, which are now identified as Australoseris, Stelidioseris, and Etallonasteria, respectively, while those originally identified as Australoseris are maintained. New results are based on a taphonomic analysis carried out to recognize the bias introduced in the systematic assignments by different preservational—taphonomic—grades. Four taphonomic grades were defined as Tg0–Tg3, with an increasing degree of taphonomic distortion. Tg0 is an ideal state with preservation of the microstructure. The loss of microstructural features occurs in Tg1–Tg3, preventing assignment at the suprageneric to the specific level. Additionally, those specimens with Tg2 and Tg3 suffered a change in their macrostructural features giving rise to apparent morphological details that may lead to wrong assignments. Tg3 is the stage of preservation most frequently seen in the field. This is not useful for systematic studies due to the loss of all diagnostic features. Samples with Tg1 are useful for systematic studies because most of the macrostructural characters are preserved almost in their original condition. Taphonomic analyses of the specimens are necessary to carry out reliable systematic studies for later measurements of richness and evenness.