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Book of Abstracts of the VI Symposium of the Miocene-Pleistocene of Central and Northern Argentina, held during November 30 - December 3, 2021 at the Autonomous City of Buenos Aires, Argentina.

Abstract Book

In the central Neuquén Basin, the Huincul Formation comprises thick successions of Upper Cretaceous fluvial deposits widely exposed at the south and north-west of Huincul High. The vertebrate fossil record from the Huincul Formation is very abundant, especially considering the saurischian dinosaurs, including several theropod (Mapusaurus, Taurovenator, Aoniraptor, Skorpiovenator, Ilokelesia, Gualicho, Overoraptor, Tralkasaurus, and Huinculsaurus) and sauropod specimens (Choconsaurus, Argentinosaurus, Cathartesaura, Limaysaurus, and the indeterminate rebbachisaurid MMCH-Pv-49). In this contribution, we describe new rebbachisaurid sauropod findings from the El Orejano locality (Neuquén Province, Argentina), where coarse sandstones outcrop referred to the lower section of the Huincul Formation. The new material includes three axial elements that we refer to Rebbachisauridae: a partial dorsal neural arch (MAU-Pv-EO-633), an incomplete dorsal vertebra (MAU-Pv-EO-634), and an almost complete caudal vertebra (MAU-Pv-EO-666). These new findings share different features with other members of that family, although show some morphological differences with other rebbachisaurid taxa, which suggest a more diversified fauna in the central Neuquén Basin than previously known, at least during the Cenomanian/Turonian interval. This record from the new fossiliferous locality of El Orejano allows us to improve our knowledge about the morphological diversity of the Rebbachisauridae during the early Late Cretaceous. Furthermore, it represents one of the most modern records of the family, adding new information on the last stages of the evolutionary history of rebbachisaurids.

The fossil record of Cretaceous turtles in Santa Cruz Province is scarce. Turtles have been reported from the Mata Amarilla Formation (Cenomanian), the Cerro Fortaleza Formation (Campanian–Maastrichtian), and the Chorrillo Formation (early Maastrichtian). In this contribution, we examined all the turtle remains recovered from six localities in the Mata Amarilla Formation, nearby Mata Amarilla farm (Santa Cruz Province, Argentina). These fossils are housed at the “Padre Molina” Museum in Río Gallegos, Santa Cruz. Most of the carapace and plastral remains are conferred to an indeterminate small species of cf. Prochelidella sp., while the remaining fragments are attributed to a mid-sized species of an indeterminate Chelidae. Prochelidella spp. is a group of turtles distributed in Chubut, Río Negro, Neuquén, and Mendoza provinces, ranging from the Aptian to the Maastrichtian, with two main gaps (late Albian and Coniacian–Santonian). The recognition of cf. Prochelidella sp. in the Austral-Magallanes Basin extends the geographic range of this group more than 500 km south to the previously known southernmost record of Prochelidella, Pr. argentinae, from the Golfo San Jorge Basin (Chubut, Argentina).

Phylogenetic studies of conifers that involve morphology are hindered by gaps in the anatomical characterization of seed cones, a direct result of difficulties encountered in sectioning cones in mature stages, which are often hardened due to sclerification. Here, we compare the resolving power of three methods—paraffin sectioning, petrographic thin-sectioning, and X-ray microcomputer tomography (micro-CT)—in documenting the morphology and anatomy of mature seed cones at different scales of detail. We use Taxodium as a case study, based on which we make recommendations on the complementarity of these methods, and we present a paraffin sectioning protocol for softening sclerified tissues. Paraffin sectioning, while providing high anatomical resolution, can only be used for small specimens, is labor-intensive, and hampered by hard tissues. Petrographic sectioning is fast and effective on larger specimens, but has low anatomical resolution and is limited to dry non-fleshy material. Micro-CT, if available, is fast, produces high resolution with no size limitations, and allows virtual sectioning and accurate 3D rendering; however, understanding of histology requires comparisons of CT images with results of the other methods. Although they overlap, each of the three methods provides unique insights on anatomy at different scales of detail. Thus, combining all three methods is ideal for producing high-quality data at all scales of anatomical and morphological detail.

Two subspecies of S. argentinus are described in Silurian levels from the Central Precordillera of San Juan, Argentina. The studied samples come from the middle to upper part of the Los Espejos Formation at the quebrada Ancha section, Talacasto area. The bearing beds consist of coquinas with clay-carbonate cement or calcarenites. Specimens of Saetograptus argentinus argentinus and S. a. robustus, in association with brachiopods, bivalves, trilobites, tentaculitoids, and ostracods, are present in the samples. The mentioned graptolite fauna, together with previous conodonts and brachiopods biostratigraphic data, allow to assign a Ludlow age for these levels. Subspecies of Saetograptus argentinus are described for the first time in the Precordillera Geological Province and enable to correlate the quebrada Ancha section with Cerro del Fuerte, La Chilca, and Loma de Los Piojos sections in Precordillera, and with Kirusillas Formation in Bolivia.

The Congress of the Argentinian Paleontological Association (CAPA), previously called the Argentine Congress of Paleontology and Biostratigraphy, took place for the first time in 1974, in San Miguel de Tucumán. From that beginning, the congress was held in different cities of the country, becoming a traditional event. During the previous edition, held in 2016 in the city of General Roca, the project to organize it and hold it again in the Autonomous City of Buenos Aires was conceived, presented and approved. In this way, and after 43 years, the congress returns to the Argentine capital in the hands of a group of professionals who carry out their research and work at the Argentine Museum of Natural Sciences (MACN) and at the University of Buenos Aires (UBA).

The Cerro Overo-La Invernada area in north Patagonia has provided a rich record of Cretaceous continental tetrapods in the last two decades, mainly from the Bajo de la Carpa Formation (Upper Cretaceous, Santonian). The dinosaur fauna from this area is diverse, including several new taxa, with abelisaurid theropods particularly abundant. Recently, a new isolated caudal vertebra (MAU-Pv-CO-598) was here recovered. Although fragmentary, it shows features that differentiate it from other abelisaurid remains previously found in this area. It is considered a mid-caudal vertebra and is mainly characterized by a longitudinal groove on the ventral surface of the centrum; a scarcely elevated transverse process with an anteroposteriorly expanded and laterally concave distal end; a longitudinal dorsal crest anteriorly extended from the anterior border of the neural spine; and small tubercles extended from the ends of the zygapophyses, which are considered as accessory interlocking structures between vertebrae. Some characters, such as the dorsal longitudinal crest and the accessory tubercles of the zygapophyses, are present also in the non-brachyrostran abelisaurid Majungasaurus. However, the transverse process is similar to that of caudal vertebrae of non-furileusaur brachyrostrans, such as Ilokelesia, Ekrixinatosaurus, and Skorpiovenator. A phylogenetic analysis here conducted clusters MAU-Pv-Co-598 with the latter three taxa. MAU-Pv-CO-598 comes from lower levels of the Bajo de la Carpa Formation than the furileusaurs Viavenator and Llukalkan. The presence of a specimen with non-furileusaurian affinities in this formation indicates that a possible replacement from non-furileusaur to furileusaur brachyrostrans occurred during the Santonian, after the proposed Turonian faunal turnover.

The Argentine Meeting on Vertebrate Paleontology (JAPV) has been held annually in our country since the 1980s. The general objective is to present, promote, disseminate and discuss the latest advances and original results of studies on fossil vertebrates in Argentina. Although originally the meeting was raised from the need for interaction between the community of vertebrate paleontologists in Argentina, during the last decades it has reached an international level that summons world specialists specialized in different topics such as: taxonomy, anatomy, paleobiology, phylogeny , paleobiogeography, diversity, evolution. With the same motivation, the 35th JAPV 2022 was held for the third time at the Egidio Feruglio Paleontological Museum (MEF), Trelew, Chubut. This institution (Associated Unit to CONICET) hosts CONICET researchers and fellows who work in various lines of research on fossil vertebrates (paleoherpetology and paleomastozoology), covering the Mesozoic and Cenozoic to the present.

Objetivo: quantificar os homens que foram convidados, incentivados e sabem sobre o direito em participar do pré-natal e parto. Método: trata-se de um estudo transversal, descritivo e com abordagem quantitativa, realizado com 67 homens que já vivenciaram a paternidade. A coleta de dados ocorreu em julho de 2019, em um município no interior de Mato Grosso, Brasil. Utilizou-se um questionário semiestruturado. Para análise, aplicou-se estatística descritiva. Resultados: observou-se desconhecimento dos participantes sobre o pré-natal (84%). A maioria relatou que nunca foram convidados (80%) ou incentivados (72%) a participarem do pré-natal no processo gestacional e desconhecem seu direito de participar do parto (88%). Conclusão: o quantitativo de homens que são convidados, incentivados e sabem sobre o direito em participar do pré-natal e parto é insuficiente para a efetivação do pré-natal masculino, logo, tornando essa realidade distante de melhores perspectivas de paternidade.