An assemblage of early Oligocene lizards (Squamata) from the locality of Boutersem (Belgium), with comments on the Eocene-Oligocene transition

A diverse, new lizard assemblage from the early Oligocene of Belgium is described. The Boutersem railway local fauna is the most species-rich lizard assemblage yet reported from the European early Oligocene. Four lizard taxa are present: Lacertidae, Anguidae, Scincoidea and Platynota. One new species is described, Folisaurus boutersemensis sp. nov. This fauna provides new insight into the profound turnover that took place during the Eocene/Oligocene boundary in Europe. The new fauna confirms a marked decrease in diversity across the Eocene/Oligocene boundary. Two groups encountered in the European late Eocene became extinct (Iguanidae*, Glyptosaurinae). Estimates of species-level extinctions range up to 80%. These estimates include members of virtually all the families present in the late Eocene. The relative importance of climate change and biotic interactions in controlling this pattern is discussed, and negative interactions between lizards and new carnivorous mammals are favoured. (C) 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 155, 148-170.