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A recurrent aspect of the fossil record is the observation of a disproportionate number of specimens or individuals of a single taxon in some deposits, which is stated as dominance. Commonly, the dominance is explained as the result of catastrophic or short-term mass death events or are proxies for palaeoecological inferences regarding gregariousness. However, taphonomic, stratigraphic and chronologic analyses of fossiliferous deposits have shown that this is not always true. To contribute to the study of dominance in fossil assemblages, we describe a probable Quaternary skeletal accumulation dominated by the extant gregarious rock-dwelling rodent Kerodon rupestris recovered from Sumidouro do Sansao, a 65 m deep pitfall cave in northeast Brazil, and discuss the palaeoecological implications of our findings. We provide taxonomic identification, taphonomic analyses, and chronological assessment. Besides K. rupestris (minimum number of individuals, MNI = 35), we recorded three taxonomic groups, that are the ground sloth Catonyx cuvieri (MNI = 1), the anteater Tamandua tetradactyla (MNI = 1), and the cougar Puma concolor (MNI = 1). The taphonomic analysis of the K. rupestris remains supports the idea that entrapment of individuals was the main process of bone accumulation and that the death of cave inhabitants followed by short transport to the main hall possibly occurred. Kerodon rupestris remains persisted on the surface of the cave deposit for different time spans and were exposed to fragmentation, weathering, invertebrate boring and encrustation inside the cave environment. Direct dating suggests differences in the ages obtained and intermittent deposition of the individuals inside the cave. It highlights the influence of taphonomic controls on gregarious taxa, such as K. rupestris, towards dominating attritional time-averaged assemblages. Furthermore, it demonstrates that such assemblages do not necessarily support inferences about single event mortality and gregariousness of the dominant taxon.

The Serra da Capivara National Park, in the southeast of State of Piaui, is widely recognized for its important archeological sites. However, in the areas surrounding the park there are also paleontological sites, especially limestone caves, where fossils of small mammals have been found. This material was recovered from deposits attributed to the Late Pleistocene and Early Holocene. Previous works have listed the occurrence of eight species of bats in two caves, Toca do Gordo do Garrincho and Toca da Janela da Barra do Antoniao. The present study reports new data on the Chiroptera from Serra da Capivara, based on cranio-mandibular fragments from three caves. From Toca do Barrigudo we identified Tonatia sp., Phyllostomus discolor and Artibeus planirostris. The latter two species have also been identified from Toca do Serrote do Artur, in addition to Lophostoma sp. and Eptesicus fuscus. From Toca do Gordo do Garrincho, the record of Desmodus rotundus is confirmed, along with the identification of Lophostoma sp. Thus, the following taxa are recorded for the first time for the Quaternary of the Serra da Capivara region: Lophostoma sp., Phyllostomus discolor and Eptesicus fuscus. All taxa currently occur in the area, except Eptesicus fuscus, which has previously been recorded for the Quaternary of Brazil, in the states of Rio Grande do Sul and Bahia, suggesting a much wider geographical distribution at least until the beginning of the Holocene, which is corroborated by the Serra da Capivara findings.

São Paulo is one of the largest cities in the world and has several characteristics that favor a diversity of urban and wild mosquitoes. Little is known about how variations in mosquito diversity and feeding preferences for different hosts in different vegetation strata can influence the risk of pathogen transmission to humans. We investigated vertical stratification of mosquitoes and its relationship with vertebrate hosts in environments with different degrees of conservation in two conservation units in the city of São Paulo. Adult mosquitoes were collected using CDC traps, aspiration and Shannon traps. After morphological identification, host blood in engorged females was analyzed by PCR with a vertebrate-specific primer set based on mitochondrial cytochrome b DNA of vertebrates commonly found in the two conservation units. Although a higher abundance of the species Anopheles cruzii and Culex nigripalpus was found in the canopy, blood not only from birds but also from humans and rodents was identified in these mosquitoes. In one of the units, Wyeomyia confusa and Limatus durhamii were found occupying mainly niches at ground level while Culex vaxus was frequently found in the canopy. Haemagogus leucocelaenus, the main vector of yellow fever, was found in low abundance at all collection points, particularly in the canopy. Species richness and composition tended to vary little between canopy and ground level in the same environment, but the abundance between canopy and ground level varied more depending on the species analyzed, the most abundant and frequent species exhibiting a predilection for the canopy. Even those mosquito species observed more frequently in the canopy did not show an association with hosts found in this stratum as most of the blood identified in these species was from humans, suggesting opportunist feeding behavior, i.e., feeding on the most readily available host in the environment. The two most common species in the study, An. cruzii and Cx. nigripalpus, may be able to act as bridge vectors for pathogens to circulate between the forest canopy and ground level.

Triodus is a well-known genus of Xenacanthiformes, previously recorded from the late Bashkirian (Lower Pennsylvanian, Carboniferous) to the middle Artinskian (Cisuralian, Permian), mainly from Laurasian deposits (Europe and USA). For the first time, this genus is recorded from the Western Gondwana, based on isolated teeth that are referred to Triodus richterae sp. nov. The new species were found associated with other shark teeth (another xenacanthiforms and a possible euselachian), palaeoniscoid teeth and scales, labyrinthodont teeth, tetrapod bony remains, macroscopic charcoal and leaf fragments. This fossil assemblage was collected in a conglomerate layer from the Barro Alto site (Sao Gabriel municipality, Rio Grande do Sul State, Brazil), with an estimated Capitanian age, from the Morro Pelado Member, Rio do Rasto Formation, Parana Basin. The new species has teeth with an almost oval base and the aboral surface has a smooth concavity and a rounded to horseshoe-shaped basal tubercle. The coronal surface of these teeth has a tricuspid crown, a rhomboid-shaped coronal button with rounded edges with a lingually directed shaft and some oral foramina predominantly situated at the lingual margin of the base and flanking the lingual shaft. The lateral cusps bear a variable number of non-branching vertical cristae, distributed from the apex to their proximal portion, making the transversal section of these cusps asterisk-shaped. Microstructurally, these teeth have both base and cusps composed of orthodentine with an opened pulp cavity. T. richterae sp. nov. represents the youngest species of Triodus, considering it comes from Capitanian (late Guadalupian) beds, which are at least 15 Ma younger than T. kraetschmeri, the previously youngest species of this genus. The depositional interpretation, as well as the fossil assemblage in the type locality of the new species and of the Rio do Rasto Formation as a whole, indicates another freshwater record for xenacanthid sharks.

The Sanga do Cabral Formation of southern Brazil has a rich fossil tetrapod assemblage and is suggested to have an Early Triassic age mainly based on the presence of the parareptile Procolophon trigoniceps . However, a Permo-Triassic age can be also suggested for this unit taking into account the presence of putative Permian taxa and some previous stratigraphic assessments. We describe here several large vertebrae from the Sanga do Cabral Formation that display a distinctive morphology that includes the presence of a transverse distance across postzygapophyses more than twice the transverse width of the centrum, and accessory articulation structures in the neural arch that remind the hyposphene and hypantrum present in some basal parareptiles and diadectomorphs. Vertebrae with a similar large size and morphology had been previously reported from the same locality as belonging to the genus Procolophon based on their parareptile appearance (mainly the presence of a swollen neural arch) and the fact that the vertebrae were collected at the same locality where a large fragmentary skull assigned to this taxon was found. However, these vertebrae lack a comparable consistent morphology with those of Procolophon and basic statistical analyses demonstrate that these vertebrae are significantly larger than those expected in the largest known Procolophon skulls of South Africa. The morphology of these vertebra is consistent with that present in seymouriamorphs, pareiasaurs and diadectomorphs, but the absence of exclusive diagnostic characters precludes an assure assignation to either of these taxa. According to their current stratigraphic range, seymouriamorphs are the most plausible postulation, as their younger representatives are known from Late Permian deposits of Russia, but the other candidates cannot be excluded. The presence of any representative of those groups in the Sanga do Cabral Formation would be important because: (1) they would represent the first and only known record of seymouriamorphs or diadectomorphs in Gondwana, regarding the characters that the described vertebrae share with these groups; (2) they would suggest a survivorship for pareisaurs up to the Latest Permian or through the Permian-Triassic boundary, according to geochronological data currently available for this unit; (3) they might also suggest a Late Permian age for at least part of the Sanga do Cabral Formation if the intraformational conglomerates that yielded the vertebrae resulted from the rejuvenation of older levels of the same unit, and they do not include reworking of stratigraphically older strata.

Karst caves are suitable environments for the accumulation and preservation of fossils. Cave deposits are often complex and the environmental conditions within cave sites result from intricate interactions between various biological, physical and chemical factors. However, it is not fully understood how the complexity of the environmental conditions of caves influences bone diagenesis. The study of the initial stages of bone diagenesis depends to a large extent on understanding the changes in the bone histology. To contribute to this issue, we examine a set of postmortem changes affecting the bone histology of Quaternary mammals that accumulated naturally in Locus 2, a pitfall site in Cuvieri Cave, located in the tropical region of Brazil. Our analyses show that bones deposited in caves may be subject to a peculiar set of environmental conditions that in tropical regions may prevent the preservation of bone histological structure. The effect of diagenetic processes on the bones differs depending on the taphonomic stage of the bone and the diagenetic alterations appear to have influenced each other. The deposition of bioclasts following the entrapment of individuals in Locus 2 favours the proliferation of bacteria on bones and appears to be important in directing the diagenetic alteration. The hydrological regime of the cave, that is recharge with potential phases of higher humidity, also is important in directing the diagenetic alteration and further decreased the preservation potential of the bone microstructure. The formation of macroscopic and microscopic cracks related to bone weathering in caves shows that the taphonomic processes peculiar to these environments are poorly understood, highlighting the need for more research to be conducted on cave taphonomy.

Myocastor Kerr, 1792 is a semi-aquatic caviomorph rodent that lives in southern South America. Pleistocene fossils of Myocastor are known from Argentina, Bolivia, Uruguay, and Brazil. This contribution is intended to clarify the taxonomic situation of the specimens of this taxon from the Brazilian Quaternary. The material was collected in late Quaternary localities from the states of Bahia, Minas Gerais, and Rio Grande do Sul. We assign these specimens to Myocastor coypus ( Molina, 1782 ). Although some variation was seen, we do not consider it significant enough to include the fossil specimens in other extinct previously described taxa or in a new taxon. The modern original range of Myocastor encompasses only southern South America, but in the late Pleistocene/early Holocene, its distribution was displaced, at least to Bahia (∼10°S), northeast Brazil. This fact could be related to the presence of more humid environments in the the late Pleistocene/early Holocene of this region in comparison with the modern days, where the Caatinga is predominant.

In this study, we performed a comparative analysis of the physical-chemical composition and pesticide residue content of lettuce, peppers, and tomatoes that were grown in organic and conventional systems. The vegetables were purchased at the Food Supply Centre of Pernambuco [Centro de Abastecimento Alimentar de Pernambuco – CEASA/PE], Pernambuco state, Brazil. The physical-chemical composition of the vegetables was determined according to the analytical procedures of the Association of Official Analytical Chemist. The minerals (Cu, Cr, Fe, K, Mn, Mg, Na, and Zn) and the heavy metals (Cd, Ni, and Pb) were assessed using atomic absorption spectrometry, and the pesticide residues were determined using a multi-residue analysis. The results were compared by means of a Student's t -test. Principal component analysis was performed to investigate the correlations between the minerals and the heavy metals. The measurements of weight, length, and width of all three of the vegetables that were assessed were higher in the conventional group. There were significant differences ( p p > 0.05). All three of the organic vegetables were higher in total dietary fibre. The composition of the minerals and heavy metals varied between all three vegetables. Contamination by pesticide residues was found in conventional peppers and organic tomatoes.

Introduction/Background Epiglottic retroflexion seems to be an important mechanism of airway protection during swallowing. Although epiglottic dysfunction has been correlated with aspiration, the kinematics alterations underlying this condition remain unclear. Two distinct movements of epiglottic inversion were described in videofluoroscopic swallowing studies (VFSS). The first epiglottic movement brings the epiglottis to a horizontal position and the second consists of its full inversion. Material and method Retrospective cohort study of 28 patients with post-stroke dysphagia admitted to our institution in 2017. Based on VFSS images, and in regard with the epiglottic mobility, two groups were assigned for comparison: one group with complete epiglottic inversion and other with partial inversion. Other parameters of VFSS were also compared. Results Of the 28 patients in the study, 68% were male (19) and 32% female (9); 28.6% of the patients had hemorrhagic stroke, 67.9% ischemic, and 3.5% ischemic stroke with hemorrhagic transformation. We found significant statistical correlation between epiglottic mechanics alterations and risk of laryngeal penetration (Fisher's exact-test; P = 0.036). Regarding other evaluated parameters, only the absence of the cough reflex was shown to statistically correlate with the risk of laryngeal penetration (Pearson's Chi2; P = 0.007). Conclusion The results suggest that epiglottis movement is an important mechanism to avoid penetration-aspiration. The absence of cough reflex in patients with laryngeal penetration (silent aspiration) emphasizes the importance of the VFSS. We are also of the opinion that this result may be related to the pre selection of patients with suspected silent aspiration. Further studies are needed to better understand the influence of these epiglottic movement alterations in the swallowing process.

Stable isotopes (δ 13 C, δ 18 O) in teeth of extinct mammals have been used as indicators of diets and climate conditions, which in turn are used for paleoenvironmental reconstructions. The first analysis of stable isotopes in Pleistocene mammals from Southern Brazil is reported here. The analyzed taxa were the notoungulate Toxodon and the proboscidean Stegomastodon from Late Middle to Late Pleistocene fossiliferous beds exposed along Chui Creek, in the coastal plain of Rio Grande do Sul State. The δ 13 C isotopes indicate that Toxodon was a mixed-feeder that fed mostly on C4 plants, while Stegomastodon was a browser to mixed-feeder with preference for C3 plants, with less C4 plants in the diet compared to modern African elephants. Comparison with carbon isotopic values in fossils of these taxa from other Late Quaternary localities in South America shows an increased proportion of C3 plants in the diets of both Toxodon and Stegomastodon in higher latitudes. The values of δ 18 O in both taxa seem to reflect the isotopic composition of the ingested water rather than the isotopic content in the plants of which they fed on, and the observed variations are likely to mirror variations of the patterns of precipitation. Paleoclimatic inferences and possible causes for the (pseudo)extinction of these taxa in southern Brazil are also discussed.

Cynodonts are an important component of Triassic tetrapod faunas and are frequently one of the dominant groups. A summary of their record during the Triassic of Gondwana is presented. Cynodonts are represented by 63 species/57 genera in Gondwana with diversification peaks occurring during the Late Anisian (particularly in Africa) and the Carnian of South America and India. Data on the number of faunas of each age and the duration (in millions of years) estimated for these faunas were integrated with cynodont generic diversity values. One of the most important turnovers in cynodonts occurred at the Late Olenekian–Anisian, involving changes in two directions: a) the record of complex bucco-lingually expanded (gomphodont) postcanines, with traversodontid cynodonts already representing an important group at the end of the Anisian; b) the record, particularly during the Anisian, of significantly large-sized cynodonts (e.g. Cynognathus and Diademodon with basal skull length between 30 to 40 cm). Considering that the global maximum peak of cynodont diversity is during the Norian–Rhaetian, the diversity of Gondwanan cynodonts for that time, eight taxa, is remarkably low.

Background Puromycin aminonucleoside-induced nephrosis is characterized by increased renal excretion of plasma proteins. We employed this experimental model to study the urinary clearance of dextran sulfate. Methods The dextran sulfate eliminated by the urine was determined using a metachromatic assay. Polysaccharide fragments were analyzed by chromatographic and electrophoretic procedures. Disaccharide composition of the glomerular heparan sulfate was assessed using digestion with specific lyases. Results In normal rats dextran sulfate is partially degraded to lower molecular weight fragments and only then eliminated by the urine. Surprisingly, in puromycin aminonucleoside-induced glomerulosclerosis the molecular size of the fragments of dextran sulfate found in the urine is the same or even lower than in control animals in spite of the marked proteinuria. Furthermore, urinary excretion of dextran sulfate decreases in the experimentally induced nephrosis. This observation cannot be totally attributed to a reduced number of physiologically active nephrons since the glomerular filtration rate decreases ∼ 32% after puromycin aminonucleoside administration while the urinary excretion of 8 kDa-dextran sulfate decreases 3-fold. The glomerular heparan sulfate shows reduced sulfation when compared with normal animals. Possibly puromycin aminonucleoside decreases the activity of kidney endoglycosidases, which reduce the molecular size of the sulfated polysaccharide, leading to a decrease in its renal clearance. Reduced sulfation of the glomerular heparan sulfate in the puromycin aminonucleoside-induced nephrosis does not alter the size of the dextran sulfate eliminated by the kidney, as suggested for protein. Conclusions Each pathological process induces a particular modification in the kidney, which in turn can affect the renal selectivity to specific macromolecules in different ways.