CONICET | Buscador de Institutos y Recursos Humanos

Throughout the last 4 years of explorations at the marine Upper Jurassic-lowermost Cretaceous Ameghino Formation in the Longing Gap (Antarctic Peninsula), a large number of vertebrates and invertebrates were recovered. The vast majority of the material is currently under preparation and study. Preliminary data indicates that the assemblage comprises mainly diverse actinopterygian fish taxa, as well as varied marine invertebrates. Also, fossil-bearing strata seem to differ in faunal content, specimens size, and preservation along three main litho/taphofacies: A) the lowermost section characterized by black siltstones and shales dominated by disarticulated fish remains (i.e., isolated bones, scales and heads), few isolated ichthyosaurs and crocodylomorphs, and several medium-sized invertebrates (ammonites, belemnites and bivalves); B) the medium section dominated by gray shales with complete, well-preserved, pyritized small fishes (halecomorphs and teleosts), delicate crustaceans, small ammonites, and bivalves; C) the upper section characterized by yellow to reddish mudstones, sandstones, and shales dominated by medium-sized, almost complete fishes (e.g., aspidorhynchiforms, pachycormiforms), isolated plesiosaurs vertebrae, an articulated marine reptile, abundant medium-sized ammonites, belemnites, and bivalves. Bromalites are extensively found in all the sections, but only at section B they are preserved in 3D providing information about diet. The rich assemblage recovered from the Longing Gap brings new perspectives for the study of the evolutionary history of marine faunas, also playing a key role for paleoenvironmental and paleogeographical inferences for southern Gondwana during Jurassic?Cretaceous times.