481 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 © 2013 International Society of Zoological Sciences, Institute of Zoology/ Chinese Academy of Sciences and Wiley Publishing Asia Pty Ltd Integrative Zoology 2014; 9: 481–497 doi: 10.1111/1749-4877.12053 ORIGINAL ARTICLE Pleistocene history of Iberomys, an endangered endemic rodent from southwestern Europe Gloria CUENCA-BESCÓS, 1 Juan Manuel LÓPEZ-GARCÍA, 2 María Angeles GALINDO- PELLICENA, 3 Rosa GARCÍA-PEREA, 4 Julio GISBERT, 4 Juan ROFES 1,5 and Jacint VENTURA 6 1 Research Group Aragosaurus-IUCA, Paleontology, Earth Sciences Department, University of Zaragoza, Zaragoza, Spain, 2 Research Group of Paleobiology and Prehistory, Human Studies Department, University of Ferrara, Ferrara, Italy, 3 Research Institute of Evolution and Human Behavior, UCM-ISCIII, Madrid, Spain, 4 GALEMIA, Conservation and Study of Forgotten Vertebrates, Madrid, Spain, 5 Department of Stratigraphy and Paleontology , Faculty of Sciences and Technology, University of the Basque Country, Gipuzkoa, Guipúzcoa, Spain and 6 Department of Animal Biology, Plant Biology and Ecology, Faculty of Biosciences, University Autonoma de Barcelona, Barcelona, Spain Abstract The extant Cabrera’s vole, Microtus cabrerae, differs in morphology and evolutionary history from the other species of Microtus. This arvicoline has unique derived features in the cranium, mandible and dentition. Proba- bly its most conspicuous features are its large size, the high skull in lateral view, the long and distally broad na- sals, and the triangle shape of the anteroconid complex, with a marked labio-lingual asymmetry of the occlusal surface of the irst lower molars. In this study, we propose a phylogenetic lineage that includes Cabrera’s vole in what until now has been the Microtus subgenus Iberomys. Paleontological information and several life histo- ry traits support the elevation of Iberomys to the rank of genus. Genus Iberomys comprises species that have ap- peared in succession during the Quaternary: in the Early Pleistocene, the extinct I. huescarensis in the Middle Pleistocene, the extinct I. mediterraneus and in the Late Pleistocene, the extant I. cabrerae. Interestingly, the ex- tant species shows several biological singularities, such as multiple polymorphic copies of the SRY male-spe- ciic gene in both males and females, and the lowest basal metabolic rate in relation to weight among arvicoline species. Likewise, its habitat requirement is unique among the Iberian arvicolines. Accordingly, the biological and paleontological data that we present in this work support the elevation of its taxonomic rank to that of ge- nus. This study also suggests a modiication of nomenclature: Microtus (Iberomys) brecciensis is replaced with I. mediterraneus and the common name of the extant M. (I.) cabrerae changed from ‘topillo’ to ‘iberon’ to im- prove conservation and protection actions. Key words: Cabrera’s vole, conservation, Iberoccitanian endemism, Iberomys, origin Correspondence: Gloria Cuenca-Bescós, Grupo Aragosaurus- IUCA, Área de Paleontología, Departamento de Ciencias de la Tierra, Universidad de Zaragoza, Zaragoza, Spain. Email: cuencag@unizar.es INTRODUCTION The extant Microtus cabrerae Thomas, 1906 is an Iberoccitanian endemism. It is actually distributed along an arch, from the southwest to the center to the south-