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Fossil freshwater carideans are very rare worldwide. Here, we present new taxonomic remarks about Beurlenia araripensis from the Early Cretaceous laminated limestones of the Crato Formation, Araripe Basin, northeastern Brazil. We analyzed five fossil samples, testing the morphological variations such as, rostrum with 5 to 14 supra-rostral spines and 2 to 3 sub-rostral spines, which appears as serrate for Caridea. This variation demonstrates a morphologic plasticity also seen in extant species of the group, such as those of the genera Macrobrachium and Palaemon.

Fossil amniotic eggs have great informative potential, especially regarding reproductive and evolutionary aspects of vertebrates. However, there are only few intact specimens or with fossilized embryos within, and the rare reported cases are mostly related to dinosaurs. In Brazil, the records of these ichnofossils are practically restricted to the Bauru Basin. This research aims to describe the first amniotic egg found in carbonate concretions in the Romualdo Formation, adding information to the study of these fossils and to the paleontological context of the basin. The specimen was collected at the Sitio Pe da Serra do Felix, in the Municipality of Simoes, Piaui State, Brazil. The methodology employed was based on Scanning Electron Microscopy, Energy Dispersive Spectroscopy and Optical Microscopy techniques, as well as computed tomography analyses. The morphological and microstructural characteristics of the shell suggests the identification of the fossil as a crocodylomorph egg. This specimen differs from other fossil eggs assigned to the aforementioned group by its small size and considerably thick shell. The tomographic sections revealed possible basic structures of an embryo inside the egg, suggesting that this is the first fossilized egg with a crocodylomorph embryonic trace found in the world. Keywords: ichnofossil, amniotic egg, embryo, Crocodylomorpha, Aptian, Romualdo Formation. Ovos amnioticos fosseis possuem um grande potencial informativo, especialmente em relacao aos aspectos reprodutivos e evolutivos dos vertebrados. Contudo, existem poucos exemplares intactos ou dotados de vestigios embrionarios em seu interior e os raros casos registrados sao em sua maioria relacionados a dinossauros. No Brasil, os registros desses icnofosseis estao praticamente restritos a Bacia Bauru. O presente trabalho objetiva descrever a primeira ocorrencia de um ovo amniotico encontrado em concrecoes carbonaticas da Formacao Romualdo, acrescentando informacoes ao estudo desses fosseis e ao contexto paleontologico da bacia. O especime foi coletado no Sitio Pe da Serra do Felix, no Municipio de Simoes, Piaui, Brasil. A metodologia empregada baseou-se nas tecnicas de Microscopia Eletronica de Varredura, Espectroscopia por Energia Dispersiva e Microscopia Optica, bem como analises de tomografia computadorizada. As caracteristicas morfologicas e microestruturais da casca sugerem que o fossil se trata de um ovo de crocodilomorfa. O especime analisado difere de outros ovos fosseis atribuidos ao referido grupo taxonomico pelo tamanho reduzido e casca consideravelmente espessa. As secoes tomograficas revelaram possiveis estruturas basicas de um embriao no interior do material, sugerindo que se trata do primeiro ovo fossilizado de crocodilomorfa com restos embrionarios do mundo. Palavras-chave: icnofossil, ovo amniotico, embriao, Crocodylomorpha, Aptiano, Formacao Romualdo.

The preservation of fossils depends on several interactions of organic and inorganic chemical processes. The hard parts, which are more suitable for fossilization, might record valuable information of biogenic processes, while the taphonomic characteristics supply information on postmortem chemical transformation. Here, X-ray fluorescence, X-ray diffraction, and infrared spectroscopy analyses were carried out in Early Eoholocene fragments of bones collected from the subsurface at Gruta do Urso Fóssil, Ubajara National Park, northeast of Ceará State in Brazil. It is suggested a lower degree of decomposition, a preservation of the original mineral composition, along with some incidence of encrustation, and the occurrence of different animal species are analyzed. These preliminary data serve as a basis for future studies involving fossil biota from the deposits of Gruta do Urso Fóssil using spectroscopic techniques.

This paper deals with xenarthrans osteoderms assigned to Dasypus aff. D. novemcinctus, Euphractus sexcinctus and Cabassous sp. The material was collected in subsurface, from 0.10 to 0.60 m in the Urso Fóssil Cave, Parque Nacional de Ubajara, State of Ceará, northeastern Brazil. The ages of sediment samples from levels 4 and 5 (depths of 0.40 and 0.50 m) were determined by thermoluminescence technique, and indicated ages of 8,000 and 8,200 years BP for each layer respectively. The presence in these layers of early Holocene xenarthrans taxa can contribute to the understanding of the biotic evolution of the northwest region of Ceará during the last 10,000 years. Two of the three identified taxa still occur in the region: Dasypus novemcinctus and Euphractus sexcinctus. The Dasypodidae fauna here reported includes animals with generalist feeding habits and current wide geographical distribution. It is suggested, therefore, that the climatic and environmental conditions in the early Holocene were very similar the actual ones, and that the absence of Cabassous may be conditioned to other factors, such as anthropogenic action and loss of habitat by fragmentation of the vegetation. Este artigo refere-se a osteodermos de xenarthras atribuídos a Dasypus aff. D. novemcinctus, Euphractus sexcinctus e Cabassous sp. O material foi coletado em subsuperfície, de 0,10 a 0,60 m na Gruta do Urso Fóssil, Parque Nacional de Ubajara, no estado do Ceará, nordeste do Brasil. As idades das amostras de sedimento dos níveis 4 e 5 (profundidades de 0,40 e 0,50 m) foram determinadas pela técnica de termoluminescência, e indicaram idades de 8.000 e 8.200 anos AP, respectivamente. A presença de táxons de xenarthras nestes níveis do Holoceno inicial, pode contribuir para um melhor entendimento da evolução biótica da região noroeste do Ceará durante os últimos 10.000 anos. Dois dos três táxons identificados ainda ocorrem na região: Dasypus novemcinctus e Euphractus sexcinctus. A fauna de Dasypodidae aqui relatada compreende animais de hábitos alimentares generalistas e com ampla distribuição geográfica atual. Sugere-se, pois, que as condições climáticas e ambientais no início do Holoceno foram muito semelhantes às atuais, e que a ausência de Cabassous pode estar condicionada a outros fatores, como ação antrópica e perda do habitat por fragmentação vegetacional.