Análise filogenética dos Mesoeucrocodylia basais da América do Sul e a evolução do Gondwana (Archosauria: Crocodyliformes)

Mesoeucrocodylia includes the crocodylians usually divided in two groups - Mesosuchia and Eusuchia. Although the latter is mainly represented by living forms, today restrict to warm and wet habitats in the Tropics, the former includes a diverse set of forms, often found in sedimentary deposits from the main Mesozoic Brasilian basins. Many are the relationship hypotheses for the Mesoeucrocodylia. However, there is dispute between the phylogenetic relationships of the basal terrestrial groups, especially in regard to gondwanic forms (to those of Gondwanic distribution). lt is near a consensus between authors that gondwanic mesoeucrocodylia form a polyphiletic group. ln the present work, were analyzed 17 basal Mesoeucrocodylia taxa from the South American Mesozoic and Gondwanic related areas. An heuristic tree search under a maximum parsimony phylogenetic analysis revealed a single fully resolved relationship hypothesis to those taxa stressing the following conclusions. The Notosuchia forms a monophyletic group that includes a few monophyletic groups, highly supported under bootstrap analysis and Bremer indexes. The monophyly of the families Peirosauridae, Baurusuchidae, and Uruguaysuchidae were confirmed, although a few taxa were transferred to maintain monophyly. Three previously unrecognized groups were identified to maintain a monophyletic taxonomy. Brooks parsimony analysis was employed to investigate the relationships of the continental blocks derived from Gondwana. Contrary to previous authors propositions, the results indicate an isolated Africa during the Upper Cretaceous, while South America was linked to Antarctica, lndia, and Madagascar.CAPESOs Mesoeucrocodylia compreendem os crocodilianos classicamente reunidos em dois grupos - Mesosuchia e Eusuchia. Enquanto o segundo é representado principalmente pelos crocodilianos viventes, hoje restritos a ambientes quentes e úmidos dos Trópicos, o primeiro inclui uma gama diversa de formas e hábitos, comumente encontrados em ambientes deposicionais das principais bacias sedimentares mesozóicas brasileiras. Diversas são as propostas de relacionamentos para os Mesoeucrocodylia, porém as controvérsias existem em relação aos grupos basais terrestres, principalmente os crocodilianos de distribuição gonduânica. O quase consenso entre autores sugere que estes formam um grupo polifilético. Nesta contribuição foram analisados 17 táxons de Mesoeucrocodylia basais do Mesozóico sulamericano e áreas relacionadas da Gondwana. Uma análise filogenética de parcimônia máxima por busca heurística de árvores revelou uma única hipótese de relacionamento completamente resolvida para estes táxons, evidenciando as seguintes conclusões. Os Notosuchia revelaram-se um grupo monofilético, no qual foram identificados alguns grupos monofiléticos inclusos fortemente suportados, tanto por análise de bootstrap quanto pelo índice de Bremer. Confirmou-se o monofiletismo das famílias Peirosauridae, Baurusuchidae e Uruguaysuchidae, ainda que tenham sido acrescidas de alguns táxons transferidos. Três novos grupos foram reconhecidos para a manuntenção de uma taxonomia monofilética. Uma análise de parcimônia de Brooks foi utilizada para investigar o relacionamento das massas continentais derivadas do supercontinente de Gondwana. Ao contrário das proposições de alguns autores anteriores, os resultados indicam um isolamento da África durante o Cretáceo Superior, enquanto a América do Sul se encontrava ligada a Antártica, Índia e Magadascar

Aurora do Tocantins, Brasil

El proyecto de investigación que enmarcó este viaje de campaña tiene como principal objetivo la prospección de las numerosas cavernas cársticas presentes en la zona en busca de restos fósiles y subfósiles, es decir, aquellos restos que datan de menos de 5 mil años, de animales vertebrados. Estos restos están en los sedimentos que rellenan total o parcialmente los corredores de las cavernas.Fundación Museo La Plat

Aurora do Tocantins, Brasil

El proyecto de investigación que enmarcó este viaje de campaña tiene como principal objetivo la prospección de las numerosas cavernas cársticas presentes en la zona en busca de restos fósiles y subfósiles, es decir, aquellos restos que datan de menos de 5 mil años, de animales vertebrados. Estos restos están en los sedimentos que rellenan total o parcialmente los corredores de las cavernas.Fundación Museo La Plat

Quantitative assessment of the vertebral pneumaticity in an anhanguerid pterosaur using micro-CT scanning

Research on the postcranial skeletal pneumaticity in pterosaurs is common in the literature, but most studies present only qualitative assessments. When quantitative, they are done on isolated bones. Here, we estimate the Air Space Proportion (ASP) obtained from micro-CT scans of the sequence from the sixth cervical to the fourth dorsal vertebra of an anhanguerine pterosaur to understand how pneumaticity is distributed in these bones. Pneumatisation of the vertebrae varied between 68 and 72% of their total volume. The neural arch showed higher ASP in all vertebrae. Anhanguerine vertebral ASP was generally higher than in sauropod vertebrae but lower than in most extant birds. The ASP observed here is lower than that calculated for the appendicular skeleton of other anhanguerian pterosaurs, indicating the potential existence of variation between axial and appendicular pneumatisation. The results point to a pattern in the distribution of the air space, which shows an increase in the area occupied by the trabecular bone in the craniocaudal direction of the vertebral series and, in each vertebra, an increase of the thickness of the trabeculae in the zygapophyses. This indicates that the distribution of pneumatic diverticula in anhanguerine vertebrae may not be associated with stochastic patterns

A new hyladelphine marsupial (Didelphimorphia, Didelphidae) from cave deposits of northern Brazil

Based on very small upper and lower molars recovered from the Quaternary limestone caves in the State of Tocantins, northern Brazil, we describe a new genus and species of a didelphimorphian marsupial. A phylogenetic analysis based on morphological + karyotypic data set recovered the new genus and species as the sister taxon to the living didelphid, Hyladelphys kalinowskii Voss, Lunde & Simons. The new taxon differs from the latter in having a slightly larger size, more inflated and blunt cusps, greater reduction in number and size of the stylar cusps, in the absence of an anterior cingulum, a deeper ectoflexus in M2, paracone and metacone subequal in M2, and narrower and eccentric protocones. The new marsupial probably weighed no more than 40 g and its molar morphology is suggestive of mixed, insectivorous-frugivorous feeding habits. Although we regard the fauna of Gruta dos Mouras cave as Pleistocene, we do not negate the possibility that a temporal mixing (“time-averaging”) of Pleistocene and Holocene specimens existed and that the newly described taxon is a living marsupial in the study area.Fil: Oliveira, Édison Vicente. Universidade Federal de Pernambuco; BrasilFil: Nova, Patricia Villa. Universidade Federal do Rio de Janeiro; BrasilFil: Goin, Francisco Javier. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Avilla, Leonardo Dos Santos. Universidade Federal do Rio de Janeiro; Brasi

A Quaternary very young juvenile Tapirus Brisson, 1762 (Mammalia, Perissodactyla) from a cave deposit in northern Brazil: taxonomy and taphonomy

During fieldworks carried out from 2009 to 2013 in Aurora do Tocantins (northern Brazil), three isolated deciduous teeth of Tapirus were recovered. Those fossils come from a sedimentary deposit of presumed Late Pleistocene–early Holocene age in a karstic cave. This contribution aims to present a new locality of fossil Tapirus from northern Brazil, describe for the first time deciduous fossil teeth for South American Tapirus and evaluate the taphonomic aspects of those fossils. The specimens probably belong to the same individual due to there are no repeated teeth and they have the same wear pattern. Furthermore, the crowns of those teeth show no evidence of abrasion produced by transport. However, some abrasion is observed on the borders of the pulp chamber of teeth. These polishing are probably resulting of a very short transport (parautochthonous). These specimens are the only record of Tapiridae in Gruta do Urso cave; due to correspond to isolated and deciduous teeth, its identification to species level was not possible. There is not yet clear evidence that may indicate the kind of death of the individual studied here.Facultad de Ciencias Naturales y Muse

A Fauna de Morcegos Fósseis como Ferramenta na Caracterização de Paleoambientes Quaternários.

This study proposes to reconstruct the paleoenvironment from Quaternary sites of the caves in the sertão baiano and Lagoa Santa region during the Pleistocene. The paleofauna of bats from these sites were compared to the extant fauna of 25 localities, representing most important Neotropical biome. This study was possible because all bat fossil species from both sites were elements of the extant Neotropical fauna, excepting Desmodus draculae. Because bats are considered goodenvironmental definers, the association of extant and fossil fauna permits the recognition of similar environments. The similarity between faunas was analyzed by Jaccard index with a posterior grouping analysis by UPGMA. The paleofauna of Lagoa Santa matched to Caatinga fauna, suggesting a dry and open environment adjacent to the Lagoa Santa cavesduring the Pleistocene. The paleofauna of sertão baiano caves matched to neither of the analyzed faunas. Most authorssuggest that fossil record of the sertão baiano caves represents a faunal mixture. The dissimilarity between the paleofaunaof bats from the sertão baiano caves and the other analyzed faunas resulted of this study is in agreement to the argumentof a faunal mixture represented by the former

Ecomorphology and feeding behavior of the Pleistocene South American equids (Mammalia, Perissodactyla, Equidae)

The fossil record of the South American Pleistocene presents two Equidae taxa: Hippidion Owen and Equus (Amerhippus) Hoffstetter. These equids were possibly sympatric and, although being considered closely related, present distinct cranial morphologies. This study aimed to verify possible variations on the masticatory patterns and dental wear between both genera, as well as to compare their rostral morphology and functional differences related to feeding habits. We performed quantitative analyses of macrowear and occlusion surface area of teeth from Toca dos Ossos (Bahia, Brazil). The morphofunctional analysis was conducted using photographs of specimens housed at the Museo de La Plata (La Plata, Argentina) and Museu de Ciências Naturais PUC Minas (Minas Gerais, Brazil), and based on the anatomy of the extant horse Equus caballus Linnaeus, due to its resemblance to E. (Amerhippus). Results showed that E. (Amerhippus) exhibits a more significant macrowear on the antero-posterior region of the teeth, while Hippidion has a more uniform wear. Analyses of occlusion surface area confirm the difference on the structure of dental enamel between genera, where Hippidion presents more complex folds. The morphofuctional analysis indicates that the rostral portion and the premaxillary shape of E. (Amerhippus) are similar to E. caballus. However, based on anatomical studies of the premaxillary region of other extinct ungulates, Hippidion exhibits morphological structures compatible with the presence of a vestibular proboscis and premaxillary region usually found on browsing ungulates. These results indicated that E. (Amerhippus) had the capacity to feed on more abrasive food items than Hippidion. Nevertheless, the morphofunctional dissimilarities on their skull suggest marked variations on their ecomorphological strategies. Therefore, these two different approaches corroborate our point of view that Hippidion and E. (Amerhippus), despite their possible sympatry, presented consistent mechanisms related to the reduction of niche overlap concerning the partition of food resources.Sesiones libresFacultad de Ciencias Naturales y Muse

Nova Ocorrência de Mamíferos do Quaternário nos Tanques de Taperoá (Paraíba) e Alagoinha (Pernambuco), Nordeste do Brasil: Implicações Paleoambientais

Este trabalho reporta novas ocorrências de mamíferos da Megafauna do Quaternário nos sítios paleontológicos de Campo Alegre (município de Taperoá, estado da Paraíba) e Lage Grande (município de Alagoinha, estado de Pernambuco), Nordeste do Brasil. São registrados os seguintes táxons: Hippidion principale (Perissodactyla, Equidae), Panochthus sp. (Cingulata, Glyptodontidae) e Gomphotheriidae indet. (Proboscidea) no depósito de tanque de Campo Alegre; e Equus (Amerhippus) neogeus (Perissodactyla, Equidae) no depósito de tanque de Lage Grande. Em termos paleoambientais e paleoclimáticos, a ocorrência dos táxons aqui reportados sugere um ambiente mais aberto associado a coberturas florestais e um clima relativamente mais úmido e quente na região de Taperoá, e áreas estritamente abertas e cobertas por pastagens e um clima relativamente mais árido em Alagoinha durante o Pleistoceno Final-Holoceno inicial