MORPHOLOGICAL IMAGING AND INTEGRATION INTO PHYLOGENETIC RESEARCH IN FOSSIL SPIDERS

The vast majority of fossil spiders are found in Cenozoic ambers, while most Mesozoic and Paleozoic finds are from Fossil-Lagerstätten deposited in water-lain sedimentary environments. Extracting morphological data of phylogenetic importance from soft-bodied animals can be challenging because the details used to identify comparative extant relatives are often small and may not preserve well. Amber presents the lesser problem, unless it is opaque, in which case modern techniques such as synchrotron x-ray computed tomography can extract exquisite details. Among sedimentary matrix-preserved fossils, however, different study techniques are necessary, and different for each facies in the fossils occur. For spiders, these range through lacustrine volcaniclastics, mudstones, siltstones and carbonates, to estuarine and marine settings. I review techniques used to extract morphological data from fossil spiders, giving some examples of amber preservation, but mostly concentrating on the wide variety of strategies used to visualize spider fossils in matrix preservation, including macrophotography, photomicrography, and scanning electronic microscopy. Using case studies, I show how the digital revolution in photography has allowed paleoarachnologists to observe morphological details which, until recently, would have been considered unpreserved or undetectable, thus enabling fossil spiders to be included in phylogenetic studies alongside their modern counterparts.