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

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

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

Técnica de Extração de Palinomorfos em Cálculos Déntarios de Gonfotérios Sul-Americanos

A laboratory technique was developed to extract palynomorphs from dental calculi of South American gomphotere Notiomastodon platensis individuals. The samples were obtained from molar specimens from Northeastern and Southern Brazil. The laboratory procedure consists in steps of maceration, addition of Lycopodium clavatum exotic spores, reaction with concentrated hydrochloric acid, washing with distilled water and sonication. Glycerin gelatin was used to prepare the microscope slides containing the microfossils. Pollen grains, pteridophyte spores and fragments of plant tissues were recovered. This methodology allows the extraction and observation of other microfossils, such as phytoliths, that might also be present in dental calculi of herbivorous mammals.Foi desenvolvida uma técnica de laboratório para a extração de palinomorfos de cálculos dentários de indivíduos do gonfotério sul-americano Notiomastodon platensis. As amostras foram retiradas de espécimes molares provenientes de localidades do Nordeste e do Sul do Brasil. O procedimento constitui-se em etapas de maceração, adição de esporos exóticos de Lycopodium clavatum , reação com ácido clorídrico concentrado, lavagem com água destilada e tamisação por ultrassom. A preparação das lâminas com os palinomorfos obtidos fez uso de gelatina glicerinada. Foram recuperados grãos de pólen, esporos de pteridófitas e fragmentos de tecidos vegetais. Esta metodologia permite a extração e observação de outros microfósseis, como fitólitos, que também podem estar presentes em cálculos dentários de mamíferos herbívoros

Les Xenarthra (Mammalia) du bassin de São José de Itaboraí (Paléocène supérieur, âge itaboraiense), Rio de Janeiro, Brésil

Nous présentons ici de nouvelles données anatomiques sur les plus anciens restes de Xenarthra. L’essentiel de ce travail porte sur des analyses morphologiques comparées entre les plaques osseuses et les os postcrâniens trouvés à Itaboraí (Paléocène supérieur, Brésil). L’ensemble du matériel se compose de plusieurs plaques osseuses, d’humérus, d’astragales isolés et d’un ulna qui appartiennent à au moins deux espèces. Les plaques osseuses sont attribuées à Riostegotherium yanei Oliveira &amp; Bergqvist, 1998, pour lequel une diagnose révisée est proposée. Les os des ceintures partagent des caractères communs à ceux de quelques taxons d’édentés. Pourtant beaucoup de ces caractères sont ambigus et la comparaison avec les Palaeanodonta du début du Tertiaire souligne des ressemblances dans l’anatomie du membre. Ainsi le Xenarthra d’Itaboraí pourrait être le groupe-frère de tout ou partie des Palaeanodonta.Here we present new information on the oldest Xenarthra remains. We conducted a comparative morphological analysis of the osteoderms and postcranial bones from the Itaboraian (upper Paleocene) of Brazil. Several osteoderms and isolated humeri, astragali, and an ulna, belonging to at least two species, compose the assemblage. The bone osteoderms were assigned to Riostegotherium yanei Oliveira &amp; Bergqvist, 1998, for which a revised diagnosis is presented. The appendicular bones share features with some “edentate” taxa. Many of these characters may be ambiguous, however, and comparison with early Tertiary Palaeanodonta reveals several detailed, derived resemblances in limb anatomy. This suggests that in appendicular morphology, one of the Itaboraí Xenarthra may be the sister-taxon or part of the ancestral stock of Palaeanodonta.</p

Comparative analysis of the vertebral pneumatization in pterosaurs (Reptilia: Pterosauria) and extant birds (Avialae: Neornithes).

Birds and pterosaurs have pneumatic bones, a feature likely related to their flight capabilities but whose evolution and origin is still poorly understood. Pneumatic foramina are present on the external surface of the bone and are reliable indicators of post-cranial skeletal pneumatization present in Pterosauria, Eusauropoda, and Neotheropoda. Here, we carried out a qualitative analysis of the position, size and number of pneumatic foramina of the cervical and thoracic/dorsal vertebrae of pterosaurs and birds, as they have the potential to challenge hypotheses about the emergence and evolution of the respiratory trait in these groups. We also discussed differences between pneumatic and vascular foramina for identification purposes. Besides phylogenetic representativeness, the pterosaur taxonomic sampling considered the preservation of specimens and, for birds, their life habit, as this relates to the level of pneumatization. Pneumatic foramina on the lateral faces of the centrum of the mid-cervical vertebrae of pterosaurs and birds differ in position and size, and those adjacent to the neural canal additionally differ in number. The avian posterior cervical vertebrae show a higher number of pneumatic foramina in comparison to their mid-cervicals, while the opposite is true for pterosaurs, suggesting differences in the cervical air sac of these clades. Pneumatic foramina were found at the base of the transverse processes of the notarial vertebrae of birds, while they were absent from some of the pterosaurs analyzed here, revealing the presence of a pneumatic hiatus in the vertebral column that might be explained due to the distance of this structure to the cervical air sac. These findings indicate that, although the overall skeletal pneumatization of pterosaurs and birds present deep homologies, some pneumatic features occurred convergently because variation in the number of pneumatic foramina along the vertebral column is related to the position of the air sacs in pterosaurs and birds and/or the habit of each species. There is an evident reduction of the pneumatic foramina in birds that have aquatic foraging and an increase in the ones which perform static soaring. Although we did not find any external anatomical difference between pneumatic and vascular foramina, we observed that vascular foramina occur at specific sites and thus identification on the basis of location is reliable