Micromammals from the 1995 Mammoth Excavation at West Runton, Norfolk, UK: Morphometric data, biostratigraphy and taxonomic reappraisal

The micromammal assemblage from the West Runton Elephant Site so far totals 16 species from the West Runton Freshwater Bed (WRFB). There are strong similarities with the arvicolid spectrum of basal layer H8 in the Koněprusy C 718 profile (Czech Republic), which accumulated under cooler conditions preceding the thermal maximum of an early Middle Pleistocene interglacial. Rare steppic indicators (e.g. Cricetus) at West Runton also imply a somewhat cooler and more continental climate than the present day, but overall the fauna is fully temperate in character. West Runton shares several stratigraphically significant small mammal taxa with Voigtstedt (Central Germany) and morphometric comparisons suggest that Voigtstedt may be slightly younger than West Runton. The presence of Mimomys savini, with a latest occurrence in the early part of Marine Isotope Stage (MIS) 15, together with the palaeomagnetic evidence suggests the WRFB may have been emplaced during the early part of MIS 17. However, given the complexity of the marine isotope curve during the early part of the Brunhes Chron and differences between global and regional climatic evolution, it is difficult to assign the normally magnetised WRFB to a particular Marine Isotope Stage (MIS).