REASSESSING THE (?)EARLY OLIGOCENE VERTEBRATE ASSEMBLAGE OF MONTEVIALE (VICENZA, ITALY)

The Monteviale caves are known since the beginning of the 18th century as a lignite resource and they were mined until 1952. The lignite strata are basically constituted of black shales and black lignite accompanied by marls and sandstones. They lie on explosive basaltic breccia originally formed by a volcanic apparatus raised within a lagoon where the Calcareniti di Castelgomberto, Early Oligocene in age, originated. During the mining activity many fossil remains were found and most of them are currently housed at the Museo di Geologia e Paleontologia dell’Università di Padova. The collection consists of about 300 specimens of fishes, amphibians, reptiles and mammals acquired by the Museum from 1875 to 1946. The major goal of this resea rch is the systematic revision of the vertebrate fauna of Monteviale which has not been exhaustively reviewed since the 1930’s. Amphibians are represented by several specimens of tadpoles of palaeobatrachids; reptiles are represented by two species of chel onians, the trionychid Trionyx (s.l.) italicus and the geoemydid Bergouniouxchelys vallisnerii vallisnerii, and one species of crocodile. The poorly preserved and abundant crocodilian remains have been originally ascribed to Crocodylus monsvialensis and C. dalpiazi; both taxa are currently considered synonyms of Diplocynodon ratelii, a species rather common in the freshwater deposits of Europe from the Late Eocene to the Middle Miocene. However, some cranial and dental characters suggest that all crocodilian remains belong to a single species of Diplocynodon, distinct from D. ratelii. Among small mammals, the big bat Archaeopteropus transiens appears to be, despite its size, a michrochiropteran while Epapheliscus italicus clearly differs from apheliscids in having different dental characters. The systematic revision of the latter species and of ?Dyspterna helbingi is still in progress. Among the large-sized mammals, about 100 specimens are referred to the rhinocerotid Epiaceratherium bolcense. This cursorial species represents the smallest rhino among the first European representatives of Rhinocerotidae and displays some plesiomorphic characters. E. bolcense is currently known only from Monteviale. The fossil collection of Anthracotherium monsvialense includes about 100 specimens. The morphology of the low crowned teeth does not show a wide range of intraspecific variation with the exception of the sexually dimorphic canines. The small small-sized A. monsvialense and the large large-sized A. magnum (more recent and widely can be placed into a trend of increasing body mass, taking into account the extreme small size of the first Asian representatives of the genus. A few fossil remains represent the genus Anthracochoerus . The occurrence of at least two species A. stehlini and A. fabianii ) and a wide dental variability are probably related to the presence of different environments in the area. Propalaeochoerus paronae represents the oldest suoid in the European continent. Its closest relatives have been collected in South South-Eas t Asia and are Late Eocene in age. The systematic validity of this genus is still debated. The vertebrate assemblage, including several species of marshy habitats, suggests an age close to the Eocene Eocene-Oligocene boundary. Most of the mammal fauna of Montevi ale shows a clear affinity with older Southern Asian forms.