Dr. D.F. (David) Mayhew

Research interests

My main current research interests are:

• evolution and taxonomy of  voles (Arvicolidae, Rodentia)
  

• biostratigraphy of the Pliocene and Pleistocene in Europe, especially the North Sea Basin
  

Arvicolid evolution and taxonomy

 The evolution of voles was rapid during the last 4 million years, and they provide unusually precise information for relative dating of  deposits, better than other lines of evidence. However, the taxonomy of fossil and recent arvicolids is complicated, with many hundreds of species having been created in the last century. Taxonomic revision is required to obtain better biostratigraphic results.

The original descriptions of many arvicolid taxa are insufficient for modern work. I am documenting with digital photography the types and referred specimens of as many of the fossil taxa as possible, in order to come to soundly based revision and simplification. This work involves international collaboration and a travel program to musea.

  Stachomys TYPE (PAN, Cracow)                     Pitymimomys TYPE, NHMUS, Budapest): 

©2010 DFMayhew/PAN Cracow/NHMUS

NOTE: These are well preserved specimens from fissure fillings. However, most of the type material of fossil arvicolids consists of  isolated teeth!

 Biostratigraphy of the Pliocene and Pleistocene in Europe, especially the North Sea Basin

Plio-Pleistocene deposits of the North Sea Basin can be subdivided on the basis of  arvicolid evolution, and cross correlations made between UK and Netherlands deposits, enabling a more complete sequence to be defined.The research program carried out in the last five years has enabled a new and more precise dating of deposits and correlation with the arvicolid biozonation of Tesakov (2004). Research is at present directed to finer subdivision of this biostratigraphy, leading to the most accurate present technique for dating the Gelasian marine deposits of the North Sea Basin and their terrestrial equivalents.

The oldest arvicolid fossils from the Netherlands were described by Mayhew et al. 2008. The remains (Mimomys hajnackensis , a primitive water vole) date back to mid-Pliocene, but were found in later inshore marine deposits of the Maassluis Formation, having probably been reworked after fossilisation. 

A major part of the program consists of revision of the UK crag arvicolids described by Mayhew and Stuart (1986), using abundant new material and leading to more precise dating of the sediments. The current interpretations of the UK sequence are demonstrated to need revision. In particular the palaeomagentic data inferences need re-examination.

 Current projects include:

• Sidestrand (UK) arvicolids (new material) in collaboration with NHM  and  University of Cambridge. Providing a more complete record of the late Gelasian faunas and enabling more precise correlation with NL.
• the Moriaanshoofd borehole (collaboration Naturalis and Rotterdam Natural History Museum) . A multidisciplinary biostratigraphic investigation into the sediments and fossil evidence underlying Zeeland, extending back into the  Early Pleistocene and Pliocene. The publication of this work is in preparation.
  
• Review of the type materials of Arvicolids in the Hungarian Natural History Museum and Geological Survey collections. So far seven type revisions are published or in press.
  
• Review of the fauna of Kislang, Hungary (in press). This paper confirms that the fauna of Kislang is a mixture of material of different age.
• Review of the fauna of Beremend-15, Hungary to establish the age of the fauna and provide a reference point
  
• Biostratigraphic correlations around the North Sea Basin. Relating the UK and NL marine and terrestrial sequences at a detailed level.
  
• The Norwich crag faunas of the crags of the Blyth Valley area, Suffolk, England. The first part of this work was presented at the INQUA SEQS meeting  Rostov, June 2010. 
  
• The Norwich crag faunas of the Sizewell area, Suffolk England (collaboration Naturalis with University of Cambridge and  Rotterdam Natural History Museum).
  
• Databank of Microtine types
• Virtual collection of  fossil microtine images per locality