Small vertebrates from the Late Pliocene Las Higueruelas locality of central Spain with new biochronological and palaeoecological inferences

The Late Pliocene fossil locality of Las Higueruelas (central Spain) has been known for many decades; however, in this paper, we describe the fauna of small-sized vertebrates (fish, amphibians, squamate reptiles, and rodents) for the first time based on pre-existing collections in the Museo Provincial de Ciudad Real. In addition to updating the taxonomical nomenclature of previously-published faunal lists, we also report the new occurrences of four fish taxa, a lizard (Lacertidae indet.), and several snakes (Malpolon gr. monspessulanus-mlynarskii, cf. Zamenis scalaris, and a large-sized indetermined viperid, probably from the Oriental vipers group or genus Daboia). The only rodent is identified as Stephanomys minor. Overall this assemblage indicates the predominance of open, dry environments and shrubby vegetation close to more grassy and riparian woodland under warm (15.1 +/- 1.8 degrees C) and semi-arid (556 +/- 40 mm) conditions. There was 4-month period of summer aridity similar to a modern Mediterranean climate. Most of the aquatic taxa (Pleurodeles, Pelophylax, and Natrix) were able to tolerate brackish environments, and the amphibians suggest the presence of deep and stable water bodies, with a long hydroperiod and aquatic vegetation, necessary for reproduction. Las Higueruelas is confirmed as being assigned to subchron 2An.1r (3.116-3.032 Ma) like the Camp dels Ninots Konservat-Lagersta center dot tten (Girona, Spain). Palaeoclimate reconstruction for both localities is consistent with the later stages of the mid-Piacenzian Warm Period. Palaeontological comparison between the two sites may support either a small difference in age, or most probably, varied climate zonations within the Iberian Peninsula, with a north-eastern area allowing a local survival of Early Pliocene taxa that are absent from Las Higueruelas.