The family Xystodesmidae (Polydesmida) includes 521 species with a center of diversity concentrated in the Appalachian Mountains. Within this family, the genus Cherokia, a monotypic taxon with the type species Cherokia georgiana, is divided into three subspecies. The last revision of this genus was made by Richard Hoffman in 1960. Here, I used morphological and molecular data sets to review the genus, and evaluate whether it is a monophyletic group. I included material from literature records and three natural history collections. Newly collected samples were obtained through a citizen science project. Morphological characters such as the shape of the paranota, body size, and coloration were evaluated. Seven gene loci were used to estimate a molecular phylogeny of the genus, and a species delimitation analysis was used to evaluate the status of the subspecies. The geographical range of Cherokia was expanded to include a newly reported state (Virginia) and ca. 160 new localities compared to the previously known range. Morphological characters such as the shape of the paranota and body size that were historically used to establish subspecies, showed a direct relation with geographical distribution and elevation (clinal variation), but not with the phylogeny. Coloration was variable and did not accord with geography or phylogeny. The phylogeny recovered a monophyletic lineage, and the species delimitation test supports a single species. The molecular and morphological evidence showed that Cherokia is a monotypic genus with the sole species Cherokia georgiana being geographically widespread and highly variable in its morphology / Master of Science in Life Sciences / Millipedes are a mega-diverse group of soil dwelling animals that feed on leaf litter. The Appalachian Mountains has a huge diversity of millipedes, in particular those in the family Xystodesmidae. Within this family, I studied the genus Cherokia, commonly known as "Georgia flat-backed millipedes". The single species in this group, Cherokia georgiana, is divided into three subspecies. The last thorough study of this genus was done by Richard Hoffman in 1960, so a modern analysis with DNA sequencing was needed to test subspecies boundaries. Here, I used hundreds of specimens from three natural history museums, and fresh specimens obtained for DNA sequencing with the help of citizen scientists. I measured the shape and size of the body and coloration patterns to determine if they were related to the geographical distribution of Cherokia. I used DNA sequencing to make an evolutionary tree of the genus. I found Cherokia individuals in Virginia for the first time and found ca. 160 new sites or locations not reported previously. The shape and size of the body was related to millipede location and elevation. Coloration was not related to geography or phylogeny, and in some localities, multiple color patterns co-existed. The genetic information from DNA sequencing indicated that all Cherokia were more closely related to each other than to any other millipede genus. In conclusion, I found that the genus Cherokia is a single species, Cherokia georgiana, that has a wide geographical distribution and a considerable diversity of body shape and color. Diversity of shape and color does not reflect subspecies boundaries but instead reflects intra-population and geographic variation.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/103633 |
| Date | 02 June 2021 |
| Creators | Vasquez Valverde, Luisa Fernanda |
| Contributors | Entomology, Marek, Paul E., Andrews, Robin M., Shear, William A. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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