A new fossil resin with biological inclusions in Lower Cretaceous depositsfrom Alava (northern Spain, Basque-Cantabrian Basin)

The occurrence of amber in Sierra de Cantabria (Alava, Basque Country) has been known for more than two decades but biological inclusions have only re cently been found. The existence of crustaceans (amphipods and isopods), ch elicerates (acari and arachnids), 12 orders of insects, and several bird fe athers are reported in this preliminary study. In addition, there are leaf remains, molluscs, and a fair number of inorganic inclusions. Pollen analysis of the elastic series indicates an age between upper Aptian -middle Albian, which allows an assignment of this stratigraphic unit to th e Nograro Formation. Chemical analysis indicates that the amber has high ma turity, which reflects its Cretaceous age. Chemical composition analysis al so indicates an araucariacean origin, which is corroborated by pollen found within the amber deposit. This new fossil site provides information for the reconstruction of paleoco mmunities of arthropods and sedimentary environments in the extreme south o f the Basque-Cantabrian Basin during the Lower Cretaceous, characterized by coniferous forests with an understory of vascular cryptograms. Some of the identified arthropods add to the fossil record for various groups that are poorly known or unknown for this time period. This Lagerstatte constitutes one of the most important deposits of Mesozoic amber in the world.