No abstract

DAS DA FORMAÇÃO BOTUCATU (BRASIL). São expostos os resultados de uma expedição pela Argentina, durante a qual foi examinado o material icnoldgico argentino referente aos tetrápodes, do Carbonffero ao Pleistocene. São descritas, classificadas, ilustradas e revisadas, aqui, de maneira preliminar, apenas as icnofaunas argentinas de idade triássica e jurassica. Tais dados são comparados com as icnofaunas de tetrápodes da Formação Botucatu, no Estado de São Paulo. Esta icnofauna é de difícil classificação, posto que se trata de uma associação completamente nova. Deve ser mencionado que o material não é, em geral, de boa qualidade. As associações Triássicas da Argentina, representadas pelas localidades de Lãs Higueras, Campo de Ischigualasto, Quebrada Los Rastros, Rio Los Tarros-Sur Pagancillo e Los Menucos, são caracterizadas pela presença, em quantidades variáveis, de terápsides e poucos arcossauros, entre os quais predominam os tecodontes quadrúpedes. Os mamíferos são raros. Pelo contrátrio, na associação jurássica de Laguna Manantiales, há uma predominância dos mamíferos, acompanhada de quatro formas dinossaurianas, e ausência de terápsides e tecodontes quadrúpedes. A Formação Botucatu, nos arredores de Araraquara, possui uma icnofauna na qual predominam os mamíferos primitivos, acompanhados de poucos dinossauròides bfpedes e poucos terápsides atribuídos tentativamente a Tritylodontoidea. A comparação detalhada entre a estrutura das diversas associações permite atribuir a Formação Botucatu, pelos menos no Estado de São Paulo, ao Jurássico Inferior ou Médio.

Recent discovery of small, tridactyl vertebrate tracks in a remote region of northwestern China has expanded the data set for the interpretation of similar trackways elsewhere in the world. Previously, similar tracks reported found in Peru from the Formation des Couches Rouges, were attributed to ornithopod dinosaurs, and then used to reinterpret the age of the section as Late Cretaceous. Similarly, the Chinese trackways were, prior to this study, assigned to the very broad chronological interval Cretaceous through Oligocene.Comparison with the similar ichnofaunas in North America and Europe where the age of the tracks is well constrained to Paleogene, and where the tracks are attributed to odd-toed ungulates (perissodactyls), necessitates careful analysis of the affinity and age of the Chinese and Peruvian trackways. In all regions the track assemblages are mammalian (i.e., of ungulate affinity). The Northern hemisphere tracks maybe be attributed to perissodactyls, but the South American tracks probably represent native ungulate groups such as the Notungulata and Litopterna, that show convergent foot morphology. Even at the high taxonomic level of odd toed ungulate such broad biostratigraphic (palichnostratigraphic) correlations are useful in providing insights into the geologic and tectonic history of terrestrial successions, where the age and faunas are poorly known.

No abstract

A new ichnotaxon is described from the Lower Jurassic (Upper Hettangian-Lower Sinemurian) carbonate tidal flats on the central-eastern Italian Alps. The narrow-gauge trackway is that of a large quadrupedal dinosaur. The pes is functionally tetradactyl with three rounded antero-medially directed digits, and the manus is pentadactyl. This quadrupedal form is close to Otozoum and Pseudotetrasauropus jaquesi both traditionally related to sauropodomorph trackmakers. The similarity with Otozoum is so marked that Lavinipes and Otozoum could be cogeneric. But the overall evidence today is that the Otozoum trackmaker was generally bipedal, whereas the trackmaker of L. cheminii is fully quadrupedal. The manual prints of L. cheminii show five short clawless digits and are different from the tetradactyl slender toed manual prints of Otozoum. The possible sauropodomorph affinity of the L. cheminii trackmaker is here discussed with an attempt to a revision of the Late Triassic-Jurassic tracks which have been traditionally related to sauropod and prosauropod.

No abstract

The Rio do Peixe rift basin developed during the Lower Cretaceous (Neocomian) and comprises the Sousa, Uiraúna-Brejo das Freiras, Pombal and Vertentes basins. In these basins, there is an abundant ichnofauna mainly composed of theropod, sauropod and ornithopod dinosaur trackways that represent the palaeontological heritage of the region. As the majority of the fossiliferous areas are located in the Sousa basin, an inventory and assessment of the scientific, educational and touristic values, together with the vulnerability of 25 palaeontological sites, is here presented and discussed. The aims of the study are to guide the strategies of geoheritage protection in the Sousa basin and to evaluate the scientific potential of the area as a geopark. In general, the geosites of the Sousa basin have low scientific and touristic values, moderate educational value and high vulnerability. The fossiliferous areas are suffering from strong natural and anthropic threats and are at high risk of degradation. For these reasons, based on the quality of the palaeontological sites, the region currently has little potential to become a geopark.

No abstract