New Methods for Classifying Fossil Spiders

Research by April Kinchloe, Recent Graduate, Department of Geological Sciences, University of Colorado

UCM #17706, Family Salticidae, Palaeodrassus cockerelli, Common Name: Jumping Spider (scale in mm). Collector Unknown. Florissant Formation

It is often difficulty to identify fossil spiders that are preserved in shale as many of their physical characteristics can be difficult to see. As a result, many spider fossils have been misidentified. April Kinchloe, a recent graduate, used a new method called morphometrics to more accurately identify Florissant fossil spiders.

Morphometrics means measuring shape, and it allows scientists to compare subtle differences in the shape of objects, which in April's work, was the shape of the spiders' carapace or outline of the body. April compiled a dataset of 202 modern spider carapace shapes, and, using morphometrics, was able to group these shapes into their respective spider families. Then she measured the carapace shapes of fossil spiders from Florissant.

	UCM # 17704, Family Aranaeidae, Eostentatrix cockerelli, Common Name: Orb Weaver Spider (scale in mm). Collector Unknown. Florissant Formation

Using both morphometrics and more traditional methods, she was able to re-evaluate and change the family-level placement of several previously misidentified fossil spiders. April discovered that seven spiders had been correctly identified, thirty-one spiders had been misidentified and twenty-two more had not been classified at all.

This study showed that there is great potential for using morphometric techniques to identify fossil spiders. Although this study focused on spiders from Florissant Fossil Beds, these methods are likely to be useful for the identification of other fossil organisms from other locations as well.

Research Collaborators:
Dena Smith, Curator of Invertebrate Paleontology, CU Museum
Robert Guralnick, Curator of Invertebrate Zoology, CU museum
Paula Cushing, Curator of Invertebrate Zoology, Denver Museum of Nature and Science

UCM #17709, Family Clubionidae, Clubiona florissanti, Common Name: Tube Spider (scale in mm). Collector Unknown. Florissant Formation.		UCM #17707, Family Salticidae, Palaeodrassus florissanti, Common Name: Jumping Spider (scale in mm). Collector Unknown. Florissant Formation

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