Durham E-Theses Geometric Morphometric analysis of the Microtus M1 and its application to Early Middle Pleistocene in the UK. KILLICK, LAURA,ELIZABETH How to cite: KILLICK, LAURA,ELIZABETH (2012) Geometric Morphometric analysis of the Microtus M1 and its application to Early Middle Pleistocene in the UK., Durham theses, Durham University. Available at Durham E-Theses Online: http://etheses.dur.ac.uk/3550/ Use policy The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that: • a full bibliographic reference is made to the original source • a link is made to the metadata record in Durham E-Theses • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders. Please consult the full Durham E-Theses policy for further details. Academic Support Oce, Durham University, University Oce, Old Elvet, Durham DH1 3HP e-mail: [email protected] Tel: +44 0191 334 6107 http://etheses.dur.ac.uk 2 Geometric Morphometric analysis of the Microtus M1 and its application to Early Middle Pleistocene in the UK. Laura Elizabeth KillickDepartments of Archaeology and Anthropology, Durham University, 2012.Thesis submitted for the qualification of Doctor of Philosophy Abstract Species of the genus Microtus are known to be some of the most rapidly evolving taxa during the Quaternary. Their remains are common in archaeological and palaeontological contexts and are frequently used in palaeoclimatic and habitat reconstructions as well as providing a key component of biostratigraphic dating models. This study focused on the dental morphology of the lower M 1 in 6 species of Microtus found in the British early Middle Pleistocene. The study examined the potential for a new approach to gaining better resolution in biostratigraphic and palaeoclimatic reconstructions in this period, using Geometric Morphometric (GMM) analyses. GMM analyses of modern samples of known origin found that it was possible to identify M1 teeth to species level with a high degree of statistical significance ( <0.0001). The application of protocols developed on modern samples to those from the early Middle Pleistocene sites at Westbury sub-Mendip and Boxgrove suggested species identification on ancient material was also possible. Taxonomic revision of the extinct species Microtus arvalinus was suggested by their morphological similarity to both modern and ancient M. agrestis samples, not M. arvalis as has previously been suggested. Identification of a large morphological disparity between modern and early Middle Pleistocene examples of M. subterraneus also suggest a complex genetic history, which previously had not been identified. Additionally, evidence for morphological differences linked to climate was found. Variation in morphology between stratigraphic levels was found to be relatively low in II most cases, even when samples were thought to be separated by a significant period of time. These findings strongly support the use of GMM methods in determining Microtus remains to species level and suggest a strong potential for their use as palaeoclimatic and relative-dating proxies, requiring further research. III Acknowledgements Firstly, I would like to thank my supervisors, Una Strand Viðarsdóttir and Mark White for their encouragement, patience, help and guidance throughout this project. Thanks are also due to staff at the Natural History Museum, London, in particular Andrew Currant and Simon Parfitt for allowing me access to their specimens and their support and advice. Chris Stringer, Danielle Schreve and the entire AHOB team who secured funding for the project and were always available to help in all matters academic and otherwise. John Stuart has likewise allowed me access to specimens and his invaluable experience. I would also like to thank my fellow PhD students who have always provided support, friendship and on occasion, much needed perspective! Finally, I would like to thank my family, especially my parents, grandparents and Meyrick Irving for their continued support and encouragement without which completing this thesis would not have been possible. IV Contents Firstly, I would like to thank my supervisors, Una Strand Viðarsdóttir and Mark White for their encouragement, patience, help and guidance throughout this project. ........................ IV Thanks are also due to staff at the Natural History Museum, London, in particular Andrew Currant and Simon Parfitt for allowing me access to their specimens and their support and advice. Chris Stringer, Danielle Schreve and the entire AHOB team who secured funding for the project and were always available to help in all matters academic and otherwise. John Stuart has likewise allowed me access to specimens and his invaluable experience. ............ IV I would also like to thank my fellow PhD students who have always provided support, friendship and occasionally, much needed perspective! ........................................................ IV Finally, I would like to thank my family, especially my parents, grandparents and Meyrick Irving for their continued support and encouragement without which completing this thesis would not have been possible. ................................................................................................ IV 1.1 INTRODUCTION ....................................................................................................................... 1 1.2 BOXGROVE AND WESTBURY SUB-MENDIP IN THE CONTEXT OF THE BRITISH AND EUROPEAN EARLY MIDDLE PLEISTOCENE ..................................................................................... 4 1.2.1- INTRODUCTION ............................................................................................................... 4 1.2.2 THE LOWER MIDDLE PLEISTOCENE IN BRITAIN ............................................................... 6 1.2.3 THE RELATIVE AGES OF BOXGROVE AND WESTBURY SUB-MENDIP IN THE CROMERIAN ................................................................................................................................................ 16 1.2.4 CORRELATIONS OF THE BRITISH LOWER MIDDLE PLEISTOCENE WITH EUROPE ........... 19 1.3 THE BIOLOGY AND BEHAVIOUR OF MICROTUS SPECIES ...................................................... 22 1.3.1 INTRODUCTION .............................................................................................................. 22 1.3.2 COMPLEX GENETIC HISTORIES. ...................................................................................... 22 1.3.3 SEXUAL DIMORPHISM. ................................................................................................... 25 1.3.4 VARIATION IN SIZE AND SHAPE. .................................................................................... 27 1.3.5 DISPERSAL RATES AND MODES ...................................................................................... 31 1.3.6 DENTAL MORPHOLOGY ................................................................................................. 32 1.4 APPLICATIONS OF GEOMETRIC MORPHOMETRIC ANALYSES ............................................... 36 1.4.1 INTRODUCTION TO GEOMETRIC MORPHOMETRIC ANALYSES ...................................... 36 1.4.2 GEOMETRIC MORPHOMETRICS AND SYSTEMATICS. ..................................................... 38 1.4.3. THE APPLICATION OF GEOMETRIC MORPHOMETRIC METHODS IN ARCHAEOLOGICAL CONTEXTS. .............................................................................................................................. 41 1.4.4 DISCUSSION .................................................................................................................... 42 V 1.5 OVERVIEW OF THESIS ........................................................................................................... 44 2.1 INTRODUCTION ..................................................................................................................... 46 2.2 BOXGROVE ............................................................................................................................ 47 2.2.1 LOCATION ....................................................................................................................... 48 2.2.2 GEOLOGICAL SETTING .................................................................................................... 49 2.2.3 STRATIGRAPHIC SUMMARY ........................................................................................... 50 2.2.3a SLINDON FORMATION- UNITS 1-5a ......................................................................... 51 2.2.3B THE EARTHAM FORMATION- UNITS 5B-11 .............................................................. 58 2.2.4 PALAEOENVIRONMENTAL INTERPRETATION ................................................................ 60 2.2.4A: SLINDON FORMATION PALAEOENVIRONMENTAL RECONSTRUCTION .................. 60 2.2.4B EARTHAM FORMATION PALAEOENVIRONMENTAL RECONSTRUCTION ................. 62 2.3 WESTBURY SUB-MENDIP ...................................................................................................... 63 2.3.1 LOCATION ....................................................................................................................... 64 2.3.2 EXCAVATION HISTORY ................................................................................................... 65