Invasive sClimatic and geological changes have had profound impacts on contemporary patterns of cave biodiversity in North America. The Mississippi River Valley has facilitated the genetic isolation, molecular divergence, and subsequent speciation in many groups of surface-dwelling animals, but its influence on the evolutionary history of cave-dwelling organisms has yet to be evaluated, in part, because the geological history of the Mississippi River and its influence on regional cave-bearing karst remain poorly understood. To investigate the evolutionary and geological processes shaping patterns of diversity in caves along the Mississippi River, we employed DNA to reconstruct the evolutionary histories of two ecologically distinct groups of terrestrial cave‐dwelling springtails (Collembola) from the Salem Plateau—a once continuous karst region, now bisected by the Mississippi River Valley in Illinois and Missouri. We find that cave-obligate springtail populations in Illinois and Missouri diverged 2.9–4.8 Ma, which we attribute to genetic isolation resulting from climatic and geological processes involved in Mississippi River Valley formation beginning during the late Pliocene/early Pleistocene—providing prima facie evidence of vicariance across the Mississippi River for terrestrial cave arthropods, and accordingly, the first biogeographic evidence for the initial timing of Mississippi River entrenchment and bisection through Salem Plateau karst in Illinois and Missouri. Lastly, the discovery of many deeply divergent, morphologically cryptic, and microendemic lineages reveals how little we understand microarthropod diversity in caves and presents major concerns for cave conservation biology.
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About the speaker
Dr. Katz recently received his Ph.D. in Entomology from the University of Illinois at Urbana-Champaign and is now a post-doctoral researcher at the U.S. Army Engineer Research and Development Center in Champaign, Illinois. His graduate research utilized springtails (Collembola)—a group of tiny, flightless, insect-like arthropods—as models to explore evolutionary and geological processes driving patterns of biodiversity. Dr. Katz has worked on several springtail research projects in Illinois and Missouri Caves, lava tubes in the Galapagos, California, and Hawaii, and beaches along the coasts of Panama.