This palynological study presents a systematic update of the Cerro de Las Cabras Formation at its type section. Thirty-three genera and 81 species of palynomorphs are incorporated, including forms recorded for the first time in the Triassic of Argentina. Additionally, 53 forms of palynomorphs were synonymized with new or already known species of the unit from the taxonomic revision of previously published material. Four new combinations were proposed: Secarisporites argenteiformis, S. lobatoverrucosus, S. verrucosus and S. volkheimerii. The palynoflora is dominated by species of the Alisporites/Falcisporites, the Cycadopites/Monosulcites, the Secarisporites/Leptolepidites, and the Densoisporites/Lundbladispora complexes. The locally common presence of Illinites (∼14%), cf. Rimaesporites (∼4%), Minutosaccus (∼2.7%), Staurosaccites (∼2.3%), Protodiploxypinus (∼2%), Angustisulcites (∼1.7%), and Brachysaccus (∼1.7%) is noteworthy. The Permian taxa Cladaitina sp., Limitisporites rectus, Lueckisporites sp., Platysaccus sp. cf. P. trumpii, Protohaploxypinus goraiensis, Punctatisporites gretensis, and Retusotriletes sp. cf. R. nigritellus are interpreted to occur in situ. The common presence of typical north-central European species such as Illinites chitonoides and Illinites kosankei, along with the co-occurrences of Densoisporites playfordii, Angustisulcites gorpii, Ovalipollis notabilis, Samaropollenites speciosus, and Staurosaccites quadrifidus, enable the constraining of the age of the palynoflora to the late Anisian–early Ladinian. On the other hand, the present study reveals a greater number of species shared with the Northern Hemisphere and low-mid latitudes of Gondwana, including typical Onslow elements such as cf. Rimaesporites aquilonalis, Samaropollenites speciosus, Staurosaccites quadrifidus, and Minutosaccus crenulatus, which allow us to ascribe the studied assemblage to a mixed Onslow-Ipswich palynoflora.

Taphonomic studies were carried out at Laguna Flecha Negra locality (Bahía Laura Complex, Middle–Late Jurassic), Santa Cruz Province, Argentina. Sedimentary facies and preservational styles were defined to recognize plant taphofacies in the studied sequence. Eleven taphofacies were identified and plant sources within a volcanic and geothermal system are proposed. Plant remains are of autochthonous to para-autochthonous origin and best preservation was found in distal facies of siliceous hot spring (sinter) systems. Lateral and vertical taphonomic differences were found in the studied sequence. These are due to changes in the sedimentary input and distance to the geothermal fluids. Results enable the reconstruction of the depositional history of this region of the Deseado Massif geological Province. We infer formation of a hot-spring (sinter) system that was subsequently destroyed by a phreatic eruption process at the margin of an andesitic effusive dome in partially reworked fall pyroclastic subfacies. After the destruction of the geothermal system, a fluvial and lacustrine epiclastic subfacies developed preserving a plant community typical of the Middle-Late Jurassic of Gondwana. Later, volcanic activity produced pyroclastic subfacies, with thick ash-fall and flow deposits from different sources and separated by a time gap that promoted fossilization of an in situ forest. Taphonomic studies of these plant communities allowed reconstruction of a chain of geological events and how these processes have influenced the preservation of a Jurassic flora from Patagonia, thus contributing to an understanding of the paleoecology of the Deseado Massif geological province.

Sites corresponding to Marine Isotope Stage MIS 5c and MIS 4 like Artazu VIII, with a continental record but no hominin imprints or carnivore activities, are very scarce in the Iberian Peninsula. The Artazu VIII cave fill (Arrasate, northern Spain) was discovered in 2013 and is presented here for the first time, including detailed stratigraphic and sedimentological descriptions of the differentiated 12 levels, as well as an ordered chronology of most levels, covering at least 36.000 years. In addition, the small mammal assemblage yielded a total of 8,129 identifiable skeletal remains corresponding to 14 taxa. The conditions inferred from the ecological preferences of the small mammal associations have been correlated with four different stages and substages from MIS 5c to MIS 4 in which the woodland mass expanded and retreated, depending on the relative temperature and humidity in each period. Finally, considering the species variability and estimated palaeoenvironment, a comparison with the NGRIP δ¹⁸O curve and other sites with the same chronology has been performed, showing that Artazu VIII is one of the few deposits attributable to the Marine Isotopic Stages previously mentioned and the only one that correlates to the Greenland Interstadial 18 from the Iberian Peninsula.

Modiomorphid bivalves from the Silurian and Devonian beds of the Central Andean Basin of Western Gondwana are herein presented. This paper is not only a systematic updated revision of certain species of modiomorphids but also includes the description of newly found ones in Bolivia. They were collected from 17 scattered outcrops along Eastern Cordillera, Eastern Altiplano, Interandean, and Subandean regions of Bolivia. A total of 55 specimens, well- to regularly-preserved, were studied. The Sphenotomorpha orientalis new species from the Interandean of Mataral is described. The genus Sphenotomorpha is reported for the first time from Ludlowian layers of the Central Andean Basin with Sphenotomorpha sp. A. Other species described and systematically discussed are Modiomorpha concentrica, Modiomorpha cf. pimentana, Sphenotomorpha ulrichi and Sphenotomorpha cf. bodenbenderi? Forms classified as Modiomorphidae indet. A, B, and C are studied and some discussions about their previous and current taxonomic designations are herein presented. The biostratigraphic distribution of the two cosmopolitan genera, Sphenotomorpha, 1916, and Modiomorpha, 1869, is proposed. From the Eifelian to the Frasnian, endobyssal forms, such as Modiomorpha concentrica, coexisted with foot forms like Modiomorphidae indet. C and Sphenotomorpha sp. B, which would have developed a discreet byssus. This research contributes to the still inaccurately known Silurian and Devonian palaeogeography of the Central Andean Basin.

A new basal notoungulate, Nanolophodon tutuca gen. et sp. nov., is described. This is represented by maxillary and dental fragments and by isolated teeth. The holotype and referred material were found at the “1968 Fissure” of the Itaboraí Basin, Rio de Janeiro State, Brazil. This basin has been regarded as early Eocene in recent contributions. The generalized appearance and brachydonty of the studied specimens, together with the presence of certain typical traits (poorly developed entolophid, well-developed metacone column, etc.) indicate that N. tutuca can be considered among the group of genera traditionally known as henricosborniids, easily distinguishable from Typotheria by the absence of crista 1 and from Toxodontia by the absence of crista intermedia. It is also different from all other henricosborniids by a combination of characters, such as the presence of a long crochet, the development of two small cristae in the ectoloph, and the large paraconid, among others. In the context of a phylogenetic analysis performed, we do not find conclusive evidence about the synonymy between Itaboraitherium atavum and Othnielmarshia pristina. In turn, we question the reference of these forms as henricosborniids, based on the complex occlusal dental pattern observed in both cases. Finally, based on the observations made in the present study, we discuss the identification of the paraconid in notoungulates, which may be associated with some cusps located mesially to the metaconid and identified as pseudoparaconids in past studies.