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    Published: December 17, 2013

    One leg at a time: The morphology of millipedes

    Stephanie Ware, Manager, Morphology Labs, SEM

    WILSON GUILLORY

    Freshman Biology major at University of Arkansas

    REU Mentor: Dr. Petra Sierwald (Curator, Arachnida and Myriapoda, S&E)

    Symposium Presentation Title: A Thousand-legged Mystery: The Evolution of Millipedes

    Symposium Presentation Abstract: Millipedes (Arthropoda: Diplopoda) are an exceptionally diverse group of arthropods with over 13,000 known species and an estimated 80,000 total, and are important nutrient cyclers in forest ecosystems worldwide. However, relatively little is known about their anatomy, ecology, and evolution, making the analysis of millipede phylogeny, morphology, and behavior very challenging. The present study generated image data for the creation of a comprehensive millipede morphological atlas. Atlas images will form the base for detailed morphological descriptions; the morphological data, when combined with molecular data, will be employed as characters for phylogenetic analyses of the interrelationships between millipede families. Selected morphological images will be integrated in a world-wide, illustrated family identification tree. Millipede specimens of four species from the orders Spirobolida, Polydesmida, and Stemmiulida were dissected and cleaned using an ultrasonic cleaner and enzymatic treatment with pancreatin. The specimens were then photographed with a light microscopic imaging system to generate detailed color images with high depth of focus. The specimens were subsequently dried and mounted for scanning electron microscopy, where they were separately imaged to allow for the examination of surface structures and features difficult to see with a light microscope due to transparency or small size. Males and females of the same species were both imaged in cases of sexual dimorphism. Several apomorphic and synapomorphic characters were noted, with especial attention paid to the mandibles and gnathochilaria. Apomorphic characters in Spirobolida included the presence of a small anterior tooth and the lack of an anterior fringe on the molar plate, while differences between families were also found. Mouthparts of Polydesmida and Stemmiulida were morphologically similar to each other, supporting a closer relationship between those two groups than to Spirobolida.

    Original Project Title: One leg at a time: The morphology of millipedes

    Original Project Description: Millipedes are the main nutrient recycler in forest ecosystems; they chew down the leaf litter for further decomposition. Despite their ecological importance for soil health, their biodiversity, morphology and general biology are severely underexplored.  The millipede research program at the Field Museum of Natural History will produce a morphological atlas of various millipede groups to develop a comprehensive identification key to millipede families. Such tools promote further research into the group, such as local species richness,  biogeography, and phylogeny. The 2014 REU project will investigate the morphology of the millipede orders Polydesmida, Julida and Stemmiulida in detail, using the scanning electron microscope and various light microscopes. High quality images will be generated for the comparative analysis of complex structures in various millipede groups, such as sense organs, mouth parts, eyes and copulatory organs.

    Research methods and techniques: The intern will be trained in millipede morphology, identification, and dissections. S/He will acquire skills to operate light and scanning electron microscopes, to produce and to manipulate images using sophisticated software. The newly generated morphological data will be added to the existing data pool, allowing comparative analyses and phylogenetic inference using these data.


    Stephanie Ware
    Manager, Morphology Labs

    Stephanie started volunteering at the Field Museum in 1998, working with Curator John Bates in the Bird Division. In 1999, John Bates hired her as a research assistant. After that project finished in 2007, she went to work for Carl Dick in the Division of Insects helping him to complete his work on the museum's Bat Fly collection. She spent a great deal of time generating images for the Bat Fly portion of theDiptera Taxonomy Database. When Carl left for University of Kentucky in 2009, she continued her imaging work in the Insect Division. In the intervening years, she has imaged hundreds specimens, mostly types, from the rove beetle (Staphylinidae), ant and myriapoda collections.

    Stephanie began working with the Chicago Peregrine Program in 2006.  Initially, she monitored the Metropolitan Correctional Center nest in downtown Chicago.  Over time, her duties have expanded to include other nests in the metro region, emphasizing the identification of nesting adults.  In March of 2007, Stephanie created a group called Midwest Peregrine Falcons on the photo sharing website Flickr with the goal of providing a place for photographers across the country to submit their photographs of peregrine sightings in the Midwestern United States. She also has many of her own peregrine photos on Flickr as well.