Diversity and paleoenvironmental implications of an elasmobranch assemblage from the Oligocene-Miocene boundary of Ecuador - Carrillo-Briceño, Jorge Domingo (University of Zurich. Palaeontological Institute and Museum) ; Villafaña Navea, Jaime A. (University of Vienna. Department of Paleontology) ; de Gracia, Carlos (University of Vienna. Department of Paleontology) ; Flores-Alcívar, F. Fernando (Universidad Estatal de la Peninsula de Santa Elena) ; Kindlimann, René (University of Zurich. Palaeontological Institute and Museum) ; Abella, Juan (Institut Català de Paleontologia Miquel Crusafont)