Lizards and amphisbaenians (Reptilia, Squamata) from the middle Eocene of Mazaterón (Soria, Spain).

The assemblage of lizards and amphisbaenians (Reptilia, Squamata) from the middle Eocene locality of Mazaterón (Spain) is described. Considering the rather limited material available for the study, the assemblage shows a moderate diversity with eight taxa corresponding to five different families. In most cases the scarcity and fragmentary nature of squamate specimens precludes a precise identification, but provides insights on identity of the groups represented. Mazaterón fills the gap between early and late Eocene Iberian localities, showing the persistence of iguanids (possibly Geiseltaliellus), lacertids (possibly Dormaalisaurus), and glyptosaur (tribes glyptosaurini and "melanosaurini") and anguine anguids through most of the Iberian Eocene. It also records the return of amphisbaenians (Blanidae) after their temporary retrieval from Europe during most of the middle Eocene, and the presence of two scincids, one of them possibly corresponding to a new taxon. The information provided by squamates complements what is already known from mammals, crocodylians, and turtles in what is arguably one of the most important vertebrate Paleogene localities of the Iberian Peninsula.