Rodent faunas of the Mio-Pliocene continental sediments of the Teruel-Alfambra region, Spain

Abstract

In the large inland basin of Teruel-Calatayud the area around the town of Teruel is well known for its numerous remains of fossil mammals. They are found in Upper Miocene and Pliocene deposits, and some groups have already been studied in detail. Simultaneous with the collecting of fossil smaller mammals a detailed lithostratigraphic survey was carried out in the area between the village Alfambra and Teruel. Five formations are recognized, of which only the Alfambra Formation appears to contain a larKe number of sites from which smaller mammals could be collected. In the layered basin deposits altogether 46 species of rodents from 34 sites were present in sufficient numbers to be recognized as separate units. They belong to the Muridae, Arvicolidae, Cricetodontinae, Cricetinae, Trilophomyidae, Zapodidae, Gliridae, Sciuridae and Castoridae. The new genus Tempestia belongs to the Gliridae. There are three new species and two new subspecies of the Muridae: Occitanomys sondaari, Stephanomys ramblensis, Apodemus gudrunae, Parapodemus gaudryi barbarae and Castillomys crusafonti gracilis. Two new species of the Cricetodontinae are described, Hispanomys peralensis and H. freudenthali. Because for many of the sites the succession could be established in the field, a reliable biozonation is the result. Six biozones are recognized which cover the Upper Vallesian, Turolian and Ruscinian Stages of the chronostratigraphic scale for continental deposits. Since the type section of the Turolian is in the area of study this correlation has a sound basis. The six biozones are compared with the units of the earlier established zonations of Thaler and Mein. Furthermore the faunal associations of a large number of European mammal localities are placed in connection with the associations of the newly established zones. The attempt to explain the quantitative composition of the Upper Vallesian and Turolian faunas (with some 80% of Muridae) failed because of the absence of a sufficient number of reliable (paleo) ecological data. The drop in percentage of the Muridae and simultaneous increase of the Arvicolidae in the Ruscinian possibly are the result of a general cooling of the climate.