PHENOTYPIC PLASTICITY OF LOWER AND MIDDLE CAMBRIAN TRILOBITES OF THE LAURENTIAN CONTINENTAL MARGIN ASSESSED BY IMAGE BASED METHODS

Comparative studies of morphometric qualities of cranidia in trilobite specimens are used to determine ranges of plasticity in basal trilobite taxa, potentially offering insights into the role phenotypic plasticity plays in the divergence of these lineages. High resolution digital and film images of trilobites in the orders Redlichiida, Ptychopariida, and Agnostida are collected for analytic purposes. Fossil specimens are obtained by hand collection from Lower and Middle Cambrian strata in the Pioche Shale of the Highland Peak NV locality; hand collection from the Middle Cambrian Wheeler Shale at Sinbad Canyon and Swasey Peak localities in the House Range of western UT; and by image collection from catalogued specimens at the Peabody Museum of Natural History, New Haven CT. Images are digitized and processed using SCION and ArcGIS software to facilitate rapid data analysis.