Mammifères miocènes de Azambujeira, niveau inférieur (Santarém, Portugal)

Abstract

Key-words: Mammals, Lower Vallesian; Azambujeira; Lower level; Tagus Basin; Santarém; Portugal Many vertebrale remains were found af Azambujcira (lower level), one of the scarce localities that yielded teeth and bones belonging to small and large sized mammals. This gives a fairly broad view of the whole faunal spectrum. The conservation of these teeth and bones (usually abraded and corroded) was possible owing to carbonate from neighbouring - Maciço Calcário - carried by a river that mainly transported feldspathic sands from Maciço Hespérico . The forms so far recognized are indicated in the Tableau. A new species, Fahlbuschia ultima. is described. Mammal fauna points out to a lowermost Upper Miocene age (lower Vallesian, lower part of MN9 zone), even though Hipparion was never found. The overall conformity between the study results of large and small sized mammals is noteworthy. It seems to be somewhat later than Nombrevilla's fauna, but older than that from Pedregueras 2c (localities in Aragon, Spain); otherwise if is a litle later than Hostalets de Pierola fauna, but older than Can Llobateres (Catalonia). Aa far as portuguese localities are concerned it is distinctly later than marine beds at Cerradoda Pedra and a little later than Aveiras de Baixo's. Typical forest forms are scarce, watery environment dwellers being almost absent. Most of the known forms (and individuals) are terrestrial. As a whole the fauna suggests a drier climate !han that of the same area during upper Middle Miocene. Very scarce freshwatcr mollusks. Characeae and Trapa, strongly suggest that the permanence of water was quite exceptional in a region crossed by a river with a very irregular hydraulic system.