Bustylus (Eutheria, Adapisoriculidae) and the absence of ascertained marsupials in the Palaeocene of Europe
Résumé
The recent description of the new adapisoriculid placental Bustylus cernaysi from the Thanetian of Cernay, and possibly of Walbeck, permits a new assessment of the systematic position of the supposed marsupial 'Perudectes' marandati from the Montian of Hainin (Belgium). The affinity between the two species is demonstrated and the species 'P.' maranduti is included in the genus Bustylus (family Adapisoriculidae) and is excluded from the direct ancestry of B. cernaysi only because of the apparent absence of the D cusp in the known sample. Comparison with the oldest known placental, Prokennafestes (otlestid), supports the eutherian nature of Bustylus muranduti and B. cernaysi. It also shows that the adapisoriculids are morphologically closer to the primitive otlestids than to the paleoryctids, which are more specialized in several respects. One general conclusion is the absence of known marsupials in the Palaeocene of Europe, their occurrence in this continent being ascertained only from the beginning of the Eocene (i.e. early Sparnacian or MP 7 reference level). Terra Nova, 3, 586-592