A new Late Agenian (MN2a, Early Miocene) fossil assemblage from Wallenried (Molasse Basin, Canton Fribourg, Switzerland)

Excavations of two fossiliferous layers in the Wallenried sand- and marl pit produced a very diversified vertebrate fauna. New material allows the reassessment of the taxonomic position of the ruminant taxa Andegameryx andegaviensis and endemic Friburgomeryx wallenriedensis. An emended diagnosis for the second species is provided and additional material of large and small mammals, as well as ectothermic vertebrates, is described. The recorded Lagomorpha show interesting morphological deviations from other Central European material, and probably represent a unique transitional assemblage with a co-occurrence of Titanomys, Lagopsis and Prolagus. Rodentia and Eulipotyphla belong to typical and well-known species of the Agenian of the Swiss Molasse Basin. Abundant small mammal teeth have allowed us to pinpoint the biostratigraphic age of Wallenried to late MN2a. The biostratigraphic age conforms to data derived from the charophyte assemblages and confirms the oldest occurrence of venomous snake fangs. The palaeoenvironmental context is quite complex. Sedimentary structures and fauna (fishes, frogs, salamanders, ostracods) are characteristic for a humid, lacustrine environment within a flood plain system

A review of the molar morphology and phylogenetic affinities of Sillustania quechuense (Metatheria, Polydolopimorphia, Sillustaniidae), from the early Paleogene of Laguna Umayo, southeastern Peru

The early Paleogene mammalian assemblages known from the red mudstones of the Lower Muñani Formation at Laguna Umayo, southeastern Perú, add significant information on the early phases of the evolution of Metatheria in South America. Two early Cenozoic vertebrate associations have been found from the Laguna Umayo area: localities LU-3 and Chulpas, both including metatherians. The Chulpas local fauna includes at least three indeterminate didelphimorphians and three polydolopimorphians: Chulpasia mattaueri, Chulpasia jimthorselli, and Sillustania quechuense (Sillustanidae). The Laguna Umayo associations have alternatively been referred to the Late Cretaceous or the early Paleogene. The highly derived, enigmatic morphology of the only known upper molar of Sillustania quechuense granted the recognition of a new family of South American metatherians: Sillustaniidae. Crochet and Sigé (1993) preliminary assumed that Sillustania was probably a caenolestoid paucituberculatan, but in their formal description they recognized the Sillustaniidae as a new family belonging to the polydolopoid polydolopimorphians. A review of the holotype and tentatively referred specimen of Sillustania quechuense led us to reassess its upper molar morphology and homologies, as well as its phylogenetic affinities. The discussion of these aspects constitutes the main purpose of this work.Fil: Chornogubsky Clerici, Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales ; ArgentinaFil: Goin, Francisco Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales ; Argentin