View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by RERO DOC Digital Library [Palaeontology, Vol. 52, Part 5, 2009, pp. 1057–1097] MORPHOSPACE OCCUPATION IN THALATTOSUCHIAN CROCODYLOMORPHS: SKULL SHAPE VARIATION, SPECIES DELINEATION AND TEMPORAL PATTERNS by STEPHANIE E. PIERCE*, , KENNETH D. ANGIELCZYKà and EMILY J. RAYFIELD *University Museum of Zoology, Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK; e-mail
[email protected] Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, UK; e-mail e.rayfi
[email protected] àDepartment of Geology, The Field Museum, 1400 South Lake Shore Drive, Chicago, IL 60605, USA; e-mail kangielczyk@fieldmuseum.org Typescript received 16 June 2008; accepted in revised form 13 November 2008 Abstract: Skull shape variation in thalattosuchians is disparity with respect to snout morphotypes, indicating examined using geometric morphometric techniques in that each group tended to explore opposite areas of order to delineate species, especially with respect to the morphospace. Phylogeny was found to have a moderate classification of Callovian species, and to explore patterns influence on the pattern of morphospace occupation in of disparity during their evolutionary history. The pattern metriorhynchids, but little effect in teleosaurids suggesting of morphological diversity in thalattosuchian skulls was that other factors or constraints control the pattern of found to be very similar to modern crocodilians: the main skull shape variation in thalattosuchians. A comparison of sources of variation are the length and the width of the thalattosuchians with dyrosaur ⁄ pholidosaurids shows that snout, but these broad changes are correlated with size of thalattosuchians have a unique skull morphology, implying supratemporal fenestra and frontal bone, length of the that there are multiple ways to construct a ‘long snout’.