Bromalitos de la Formacion Ameghino (=Nordenskjöld) Jurasico superior de la peninsula Antarctica

We present the study of the bromalites retrieved from the Upper Jurassic Ameghino (=Nordenskjöld) Formation at Longing Gap inthe Antarctic Peninsula. The material was morphologically and chemically analyzed. We made a qualitative study and a taphonomic analysis ofthe specimens and tested paleobiological and paleoecological hypotheses. We conclude that the samples analyzed are coprolites and proposea new ichnotaxon, Antarctoscoprus longinensisichnogen. and ichnosp.nov., characterized by being a small and flat coprolite differing from otherichnogenera by its composition, which consists mainly of actinopterygian remains (e.g., scales, vertebrae, skull bones, and teeth). Antarctoscopruslonginensisincludes three morphotypes (i.e., circular, subcircular, and elongated) derived from an elongated three-dimensional original form bycompactation. Based on the internal content, we infer the producers of the coprolites were carnivorous predators, putatively an ichthyophagoustaxon. Due to the abundance of actinopterygians—mainly aspidorhynchids and ichthyodectids— and the size of the coprolites we proposemacropredator fishes as the putative producers. The mainly undisrupted fish carcasses and coprolites allow us to conduct further studies thatmight lead to a better understanding of the ancient communities living in the Late Jurassic Sea that surrounded Antarctica.