A new giant cricetine from the basal Pliocene of Mallorca (Balearic Islands, western Mediterranean): biostratigraphic nexus with continental mammal zones

Abstract

A new insular giant species of Apocricetus (M1 length > 4.22 mm, upper teeth row length > 10.90 mm) is described from dental, mandibular and cranial material recovered at the Na Burguesa-1 site (Mallorca, Balearic Islands, western Mediterranean), a Zanclean palaeokarst deposit chronologically close to the refilling of the Mediterranean after the Messinian Salinity Crisis. Apocricetus darderi sp. nov. shows a close relationship with the mainland species A. alberti (MN13), an Iberian taxon, from which it differs in size, the presence of labial and lingual anterolophids in m1, triple anterolophulids frequently developed, a reduced anterosinusid in m2 and m3 and, occasionally, the presence of an ectomesolophid in m3. Apocricetus darderi sp. nov. becomes the first endemic Balearic mammal that can be confidently assigned as having a direct mainland relative, providing the first solid palaeontological evidence of a Messinian origin for the Plio-Pleistocene fauna of Mallorca. Tragomys macpheei from the Caló den Rafelino site (Early Pliocene, probably late MN14 or early MN15) displays a peculiar selenodont teeth pattern and a high degree of hypsodonty, and is considered to be either a direct descendant of Apocricetus darderi sp. nov. or a sister taxon derived from a common ancestor.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:0EBF0B6E-2922-4A14-A6C3-8FC8D751647F

Keywords:

• Insular fauna
• rodents
• Apocricetus
• Early Pliocene
• Mallorca
• Balearic Islands

Acknowledgements

We are indebted to Dr. Harald Pieper for supplying us two subadult specimens of Cricetus and Dr. Rainer Hutterer (Zoologische Forschungsmuseum Alexander Koenig, Bonn) for the temporary loan of two adult specimens of the same species. We are also thankful to Dr. D. Jaume (IMEDEA) for his assistance. The SEM images were acquired at the Serveis Científico-Tècnics of the Universitat de les Illes Balears (Fernando Hierro). The breccias from NB-1 were discovered by Dr. Damià Vicens and permission to collect the material was obtained under the authorisation of land owners (Zaforteza family) and the General Direction of Heritage of the Consell de Mallorca. This paper has been greatly improved by the comments of Dr. Raef Minwer-Barakat and an anonymous reviewer, to whom we are most grateful. Dr. M.S.N. Carpenter post-edited the English style and grammar.