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We describe for the first time the presence of straight, curved and quasi‐helical burrows preserved in plan, oblique and transversal views in the aeolian strata of the Permo‐Triassic Buena Vista Formation (Paraná Basin), Rio Grande do Sul, southern Brazil. The morphology of the burrows is similar to that of others found in Guadalupian to Early Triassic‐aged deposits in several parts of the world. Of these, middle Permian dicynodont‐bearing helical burrows (Daimonelix) and Early–Middle Triassic kidney‐shaped burrows (Reniformichnus), both from the Karoo Basin of South Africa, show a remarkable similarity to the Brazilian burrows, prompting a discussion of the probable producers. Dicynodonts, cynodonts, therocephalian and/or procolophonians are among the probable producers of such burrows, based on size compatibility between the burrows and estimates of body size for the fossil taxa, along with the presence of skeletal adaptations in Permo‐Triassic tetrapods for digging (bone micro‐ and macrostructure). Last, we discuss some behavioural aspects of the producer of the burrows, mainly due to the presence of passive filling and bilobate bottoms in the tunnels, which indicates that they remained open as long as they were occupied. The burrows were excavated in a dry aeolian system that occurred in the Guadalupian–Induan interval of Brazil, representing the oldest unambiguous record of tetrapod dwelling structures in such an environment, and providing new and unprecedented information regarding the colonization of deserts by tetrapods during the end‐Permian biotic crisis. [ABSTRACT FROM AUTHOR]

Dicynodonts represent a speciose clade of non-mammalian synapsids that lived from the middle Permian to the Late Triassic, exhibiting a Pangaean distribution. The South American Norian fossil record is represented by two species: Jachaleria colorata from Argentina and J. candelariensis from Brazil. The Brazilian specimens come from a relatively small quarry located in the site known as Botucaraí or Botucaraí Hill (Candelária, Rio Grande do Sul). We describe here four dorsal vertebrae of a single individual referred to cf. Jachaleria candelariensis from a site named Alto Guarda Mor, located in the Faxinal do Soturno municipality, State of Rio Grande do Sul, Brazil. This taxonomic proposal and the lithological features of the site support that the outcrop belongs to the Riograndia Assemblage Zone (AZ; Candelária Sequence, Santa Maria Supersequence). Although the specimen cannot be referred unambiguously to Jachaleria candelariensis due to the lack of cranial material, it likely represents the second record of the genus in the Triassic of Brazil. We further discuss the faunal composition and relative age of some sites referred to the Riograndia AZ, which exhibit odd faunal context likely representing an AZ between the top of the Hyperodapedon AZ and the base of the Riograndia AZ. [ABSTRACT FROM AUTHOR]

The Rio Grande do Sul Coastal Plain (southern Brazil) is composed of extensive marine and continental deposits related to at least four lagoon-barrier systems of Pleistocene−Holocene age. Part of these deposits is currently submerged and passing through erosion processes by waves. Vertebrate and invertebrate body and trace fossils are constantly exhumed from these deposits and redeposited on the modern beach face. Among them, a total of 253 fragments of crustacean burrows were collected for this study. Two ichnospecies of Ophiomorpha Lundgren, 1891 were recognized (O. nodosa Lundgren, 1891 and O. puerilis Gibert et al., 2006), but most of the materials can only be assigned to the 'SOT' group (Spongeliomorpha de Saporta, 1887, Ophiomorpha, and Thalassinoides Ehrenberg, 1944), mainly because of the lack of a pelleted lining. The absence of pellets and, as a consequence, the ichnotaxonomy of these specimens, is related to taphonomical processes (exhumation, reworking, and transportation) that acted during formation of the ex situ assemblage. The paleoenvironmental dynamics and a taphonomical model are presented to demonstrate how these processes affected the trace fossils since their construction, through exhumation until deposition. Neoichnological observations led us to infer larger producers in comparison to the extant ghost shrimp Sergio mirim (Rodrigues, 1971). [ABSTRACT FROM AUTHOR]

Sharks are cartilaginous fish that appeared 245 million years ago and became a highly diversified group, occupying several niches successfully. On the coast of Rio Grande do Sul, Brazil, shark fossils are commonly found ex situ associated with accumulations of biodetrital gravels along the current beach line. The present study consisted of a faunistic and paleobiologic survey of sharks from the Quaternary in the southern region of the Rio Grande do Sul Coastal Plain (RSCP), southern Brazil. Based on taxonomy, about 3611 fossilized shark teeth collected on the beaches of Cassino and Hermenegildo were analyzed. A total of 13 taxa were identified, among them cf. Carcharhinus brachyurus , cf. Carcharhinus leucas , cf. Carcharhinus longimanus , Carcharhinus sp., Carcharias taurus , Carcharodon carcharias , Galeocerdo cuvier , Galeorhinus galeus , Isurus oxyrinchus , Notorynchus cepedianus , Rhizoprionodon sp., Sphyrna sp. and Squatina sp. Besides the already known species, here we also report the presence of Carcharhinus brachyurus , Carcharhinus longimanus , Galeorhinus galeus , Rhizoprionodon sp. and Squatina sp. as the first fossil record in the Pleistocene of Brazil for these taxa in the region. The study showed that the fossil taxa identified are similar to those extant taxa that inhabit the coast of Rio Grande do Sul. Evidence of climate oscillations that occurred during the Quaternary can be seen throughout the presence of the species Carcharhinus leucas , Carcharodon carcharias, and Galeocerdo cuvier (when compared to the composition of the modern shark fauna). Since, currently, the occurrence of these species are given as rare in the region. The present study expanded the occurrence of fossil species on the coast of the state of Rio Grande do Sul and confirmed the occurrence of populations of Carcharias taurus , Carcharodon carcharias , Carcharhinus sp., and Carcharhinus leucas during the Quaternary. • 13 shark fossil taxa from the Quaternary were identified in the Rio Grande do Sul Coastal Plain. • There are similarities between the fossil and recent Quaternary shark fauna on the east coast of Rio Grande do Sul, Brazil. • Climatic fluctuations during the Quaternary would alter the distribution of shark taxa. [ABSTRACT FROM AUTHOR]

Coprolites provide information about the presence, diet, and feeding behavior of the producer, besides the trophic relationships between extinct taxa and the regional paleoclimatic context where these organisms lived. Here, we present a paleobiological and paleoecological investigation of a Late Pleistocene carnivore coprolite found in southern Brazil (Touro Passo Formation, Rio Grande do Sul). Our analyses include morphological and morphometric approaches employing scanning electron microscopy, energy-dispersive X-ray spectroscopy, and CT-scanning. The analyzed coprolite is cylindrical, measuring 180 mm in length and 40 mm maximum in diameter, and contains a high proportion of phosphorus and calcium. Interestingly, it presents a large quantity of 102 osteoderms attributed to a Pleistocene ground sloth (Mylodontidae indet.). The size and contents of the coprolite suggest that it was produced by a large carnivorous animal comparable to representatives of Smilodon or another large carnivore mammal. The structure of the osteoderms resembles the morphological pattern found in Mylodontidae, but they are smaller than those described for adult individuals, suggesting that the coprolite producer possibly fed on a juvenile ground sloth. Palynological analysis was also performed, and the low pollen content indicates accidental consumption of plants or pollen, through the viscera of the prey or with the ingestion of water. These paleoenvironmental data suggest that the coprolite producer may have inhabited floodplain regions near river courses, where the coprolite was deposited. These results help to understand the ecological dynamics during the Late Pleistocene of South America. • A record of one of the few coprolites in South American Pleistocene. • Multi-proxy analysis indicate a large carnivore producer (e.g. Smilodon). • More than 102 Mylodontidae osteoderms preserved in the matrix. • The palynological analysis indicates dry and cold grassland environment. [ABSTRACT FROM AUTHOR]

Macroscopic charcoal has been recovered from a bonebed from the Barro Alto outcrop, Middle Permian (Guadalupian), Rio do Rasto Formation, in the southernmost part of the Paraná Basin, Brazil. During this time, a global biotic crisis was taking place and changes in the palaeofloristic composition can be observed. Records of palaeowildfires from the Guadalupian Period are scarce on a global scale. In the Paraná Basin low plant diversity, compared to the entirety of Gondwana, persists and just a few plant bearing localities have so far been described from the northern part of the basin. In the studied locality, macroscopic charcoal could be detected in an outcropping bonebed and the occurrence of palaeo-wildfires was confirmed. Besides representing the first palaeobotanical data for the Guadalupian of the southern part of the Paraná Basin, the charcoal remains analyzed here are also a significant record of the local environmental conditions during the increase in aridity observed during the Guadalupian and Lopingian in Gondwana. This contributes to the understanding of regional changes that took place during this interval. [ABSTRACT FROM AUTHOR]