The karyotype of Cabassous unicinctus (Dasypodidae, Xenarthra)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

The fetomaternal interface in the placenta of three species of armadillos (Eutheria, Xenarthra, Dasypodidae)

Background: Placental characters vary among Xenarthra, one of four supraordinal clades of Eutheria. Armadillos are known for villous, haemochorial placentas similar to humans. Only the nine-banded armadillo has been well studied so far. Methods: Placentas of three species of armadillos were investigated by means of histology, immunohistochemistry including proliferation marker, and transmission and scanning electron microscopy. Results: The gross anatomy differed: Euphractus sexcinctus and Chaetophractus villosus had extended, zonary placentas, whereas Chaetophractus vellerosus had a disk. All taxa had complex villous areas within the maternal blood sinuses of the endometrium. Immunohistochemistry indicated the validity of former interpretations that the endothelium of the sinuses was largely intact. Tips of the villi and the columns entering the maternal tissue possessed trophoblast cell clusters with proliferation activity. Elsewhere, the feto-maternal barrier was syncytial haemochorial with fetal vessels near the surface. Conclusions: Differences among armadillos occurred in regard to the extension of the placenta, whereas the fine structure was similar. Parallels to the human suggest that armadillos are likely to be useful animal models for human placentation.

Icnofósseis (paleotocas e crotovinas) atribuídos a mamíferos extintos no sudeste e sul do Brasil

ICHNOFOSSILS (PALEO-BURROWS and CROTOVINES) ATTRIBUTED TO EXTINCT MAMMALS IN SOUTHEASTERN and SOUTH BRAZIL. This work presents information regarding tunnels which are attributed to large extinct mammals. These structures can be found in several places in southeastern and southern Brazil, in different types of substrate, occurring as hollow structures (paleo-burrows) or those filled with sediments (crotovines). The dimensions and osteoderm and claw imprints found along the internal walls of the paleo-burrow found on aluvial fan deposits near the town of Cristal (Rio Grande do Sul State) suggest that a dasypodid xenarthran might have dug this structure. Comparison with similar structures found in Argentina can provide more detailed information regarding the paleoecology and biostratigraphy of the organisms that made these burrows.

Geologia e paleontologia de depósitos fossilíferos pleistocênicos do Rio Grande do Norte

This study deals with origin, sedimentary filling and fossil content of three tanks situated at Antônio Martins, Barcelona, Rui Barbosa, and Apodi counties, Rio Grande do Norte State. In addition, fossil materials from the Câmara Cascudo Museum - UFRN - Fundação Amigos do Lajedo Soledade - FALS, and from private ownership were investigated. The following families were identified: Megatberiidae, Gomphotheriidae, Mylodontidae, Equidae, Felidae, Canidae, Hydrochoeridae, Camelidae, Cervidae, Dasypodidae, Glyptodontidae, Macraucheniidae, Toxodontidae, and an undetermined Edentata Pilosa. The megafauna analysis indicated that herbivorc families occur mainly in tanks, whereas carnivore families occur in a vast proportion in an investigated ravine. Taphonomie analyses were limited to physical features because the vast majority of fossils were previously colleted without appropriate care for this kind of study. The main fossization processes were identified during diagenetie investigation. Permineralization is the most important process and replacement is the secondary one during fossilization. The study concluded that paleoenvironmental conditions during the late Pleistocene were more humid than the current one. Tropical savana, characterized by fields and cerrados , was the dominant vegetation

Importance of xenarthrans in the eco-epidemiology of Paracoccidioides brasiliensis

Background. Several pathogens that cause important zoonotic diseases have been frequently associated with armadillos and other xenarthrans. This mammal group typically has evolved on the South American continent and many of its extant species are seriously threatened with extinction. Natural infection of armadillos with Paracoccidioides brasiliensis in hyperendemic areas has provided a valuable opportunity for understanding the role of this mammal in the eco-epidemiology of Paracoccidioidomycosis (PCM), one of the most important systemic mycoses in Latin America. Findings. This study aimed to detect P. brasiliensis in different xenarthran species (Dasypus novemcinctus, Cabassous spp., Euphractus sexcinctus, Tamandua tetradactyla and Myrmecophaga tridactyla), by molecular and mycological approaches, in samples obtained by one of the following strategies: i) from road-killed animals (n = 6); ii) from naturally dead animals (n = 8); iii) from animals that died in captivity (n = 9); and iv) from living animals captured from the wild (n = 2). Specific P. brasiliensis DNA was detected in several organs among 7/20 nine-banded armadillos (D. novemcinctus) and in 2/2 anteaters (M. tridactyla). The fungus was also cultured in tissue samples from one of two armadillos captured from the wild. Conclusion. Members of the Xenarthra Order, especially armadillos, have some characteristics, including a weak cellular immune response and low body temperature, which make them suitable models for studying host-pathogen interaction. P. brasiliensis infection in wild animals, from PCM endemic areas, may be more common than initially postulated and reinforces the use of these animals as sentinels for the pathogen in the environment. © 2009 Bagagli et al; licensee BioMed Central Ltd.

Vertebrados fósseis do estado de Goiás, com ênfase em sua fauna de amniotas, compreendida entre o período permiano e a época pleistoceno

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Evolução cromossômica na Ordem Xenarthra

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Filogenia molecular dos xenarthra (Mammalia): análise do grupo cingulata a partir de sequências nucleotídicas do gene mitocondrial rRNA 16S

Os Xenarthra são o grupo de mamíferos que inclui os tatus, os tamanduás e as preguiças. A América do Sul serviu de cenário para a história natural do grupo que, somente no fim do Cenozóico, dispersou-se para a América Central e, com uma perda de variedade, chegou à América do Norte e à algu-mas ilhas do Caribe. Trinta e uma espécies estão descritas dentro da linha-gem dos Xenarthra. Elas estão classificadas em 13 gêneros, quatro famílias (Bradypodidae, Megalonychidae, Myrmecophagidae e Dasypodidae) e duas ordens (Cingulata e Pilosa). A filogenia deste grupo tem sido alvo de diver-sas pesquisas que analisaram tanto dados morfológicos, quanto moleculares. Delsuc et al. (2003) analisaram seqüências de genes mitocondriais e nucleares e confirmaram a monofilia das três subfamílias (Dasypodinae, Euphacti-nae e Tolypeutinae) inclusas na família Dasypodidae. Delsuc et al. (2003) geraram a seguinte árvore: (((Bradypus, Choloepus)100, ((Myrmecophaga, Tamandua)100, Cyclopes)100), ((D. kappleri, D. novemcinctus)100, (Toly-pentes, (Priodontes, Cabassous)54)100, (Zaedyus, (Euphractus, Chaetophrac-tus)60)100)). Gaudin (2005) apresentou um trabalho que reviu e ampliou as análises morfológicas apresentadas até então, concluindo que os tatus atu-ais estão divididos em dois grupos, um mais basal (Dasypodinae) e outro mais derivado (Euphractinae), de acordo com o seguinte arranjo: (Bradypus, Tamandua), (Dasypus, (Priodontes, (Cabassous, (Tolypeutes, (Euphractus, Chaetophractus, (Zaedyus, Chlamyphorus)42)36)72)72)40)85). Neste traba-lho utilizou-se parte do gene mitocondrial rRNA 16S de 12 táxons atu-ais de Xenarthra para analisar a filogenia do grupo através do critério de máxima verossimilhança. Nossos resultados são apresentados analisando-se o gene 16S e analisando o banco de dados do 16S mais o de Delsuc et al. (2003). Nas duas situações, as filogenias apresentadas apóiam os resulta-dos de Delsuc et al. (2003): (Bradypus, (Choloepus, ((Cyclopes, (Myrme-cophaga, Tamandua)100)100, (Dasypus, (((Cabassous, Priodontes)68, Toly-peutes)100,((Chaetophractus, Euphractus)65, Zaedyus)100)100)100)100)100). Uma melhora nos valores de bootstrap nos ramos dentro das sub-famílias da família Dasypodidae é percebida em relação ao trabalho de Delsuc et al. (2003). Acreditamos que Elementos de Transposição do tipo (LINES) são os marcadores moleculares mais adequados para confirmar o arranjo obtido com as seqüências de genes mitocondriais e nucleares.

Placentation in the anteaters Myrmecophaga tridactyla and Tamandua tetradactyla (Eutheria, Xenarthra)

Background: Since Xenarthra are serious candidates for being basal to Eutheria, their characteristics, e.g. the placental system, influence perceptions of evolution. However, in the subgroup containing the anteaters, data are very limited. The present study aims to elucidate the nature of the feto-maternal interface in the anteater placenta and to interpret these data within an evolutionary context. Methods: Placentas of two species were investigated with histology, immunohistochemistry and transmission electron microscopy. Results: Remnants of the maternal vessel endothelium were absent, resulting in a fully haemochorial barrier throughout the placenta. Two structurally different parts, the villous and trabecular areas were complex and intermingled. In particular, the trabeculae which consisted of cellular, proliferative trophoblast, associated with connective tissue, were attached to the decidua. The villi contained fetal capillaries and hypertrophied mesenchymal cells that occured near the surface near the end of gestation. The surface of the villi consisted of flat, syncytial trophoblast, interspersed with proliferative trophoblast cells. Conclusions: Based on fundamental differences between anteaters and armadillos, we inferred that placental evolution was more complex than previously thought. The haemochorial pattern of anteaters was likely an ancient condition of xenarthrans. Consequently, villous placentation may be attributed, at least in part, by convergent evolution, but was also characterized by some features that were widespread among xenarthrans.

Macroscopic and microscopic analysis of the tongue of the common opossum (Didelphis marsupialis)

We performed a macroscopic and microscopic study of the tongues of common opossums, Didelphis marsupialis, from South America. We studied two males and two females. We collected morphometric data on the tongue with precision calipers. For the light microscopy and scanning electron microscopy analyses, we fixed tissue fragments in 10% formaldehyde and 2.5% glutaraldehyde, respectively. The opossum tongues averaged 5.87 +/- 0.20 cm in length, 3.27 +/- 0.15 cm in width at the lingual body, and 3.82 +/- 0.15 cm in width at the root. The mean thickness of the lingual body was 1.8 +/- 0.1 cm, and the thickness of the root was 3.82 +/- 0.15 cm. Sharp filiform papillae were scattered across the entire tongue; conical filiform papillae occurred on the lingual body and tongue tip; fungiform papillae were scattered among the filiform papillae on the lingual body and tongue tip; and there were three vallate papillae at the root of the tongue. We found two strands of papillary projections in the tongue root. Despite the low variability observed in the lingual papillae, the morphological data obtained in this study may be related to the opossum's diverse food habits and the extensive geographic distribution of the species throughout America. Microsc. Res. Tech. 2012. (c) 2012 Wiley Periodicals, Inc.

Icnofósseis (paleotocas e crotovinas) atribuídos a mamíferos extintos no sudeste e sul do Brasil

ICHNOFOSSILS (PALEO-BURROWS and CROTOVINES) ATTRIBUTED TO EXTINCT MAMMALS IN SOUTHEASTERN and SOUTH BRAZIL. This work presents information regarding tunnels which are attributed to large extinct mammals. These structures can be found in several places in southeastern and southern Brazil, in different types of substrate, occurring as hollow structures (paleo-burrows) or those filled with sediments (crotovines). The dimensions and osteoderm and claw imprints found along the internal walls of the paleo-burrow found on aluvial fan deposits near the town of Cristal (Rio Grande do Sul State) suggest that a dasypodid xenarthran might have dug this structure. Comparison with similar structures found in Argentina can provide more detailed information regarding the paleoecology and biostratigraphy of the organisms that made these burrows.