Systematic Studies Of Polydesmidan Millipedes (Diplopoda, Polydesmida).
thesisposted on 2016-02-25, 00:00 authored by Michael C. Jorgensen
The overall objective of this thesis is to advance our existing body of knowledge of polydesmidan systematics through three research projects. The first project (Chapter 2) is a review of the genus, Docodesmus (Pyrgodesmidae). A complete taxonomic history of the genus is presented for the first time. The diagnostic characters of the genus are evaluated and potential close affinities with several other pyrgodesmid genera are discussed. All 22 species currently assigned to the genus are listed with complete synonymies, citations and diagnoses, and some necessary taxonomic revision is made. The second project (Chapter 3) is a review of the concept of subspecies. The practice of designating subspecies is assessed here through a thorough review of all subspecies designations of polydesmidan millipedes over a 50-year period. The survey focuses on the justification given for subspecies recognition, the amount of data available for the designation, the handling of nominate subspecies and the criteria used for diagnosis. Several problematic issues are addressed and suggestions to enhance future work are provided. Three examples of subdivided species from the Euryuridae are presented in detail with some taxonomic revision. The third project, which is spread out over three chapters, is a thorough systematic study of the family Euryuridae. The first part (Chapter 4) concerns the description of a newly discovered species and the dismissal of another controversial one. This chapter also includes an introduction to the taxonomic history of the family name. The second part (Chapter 5) is a phylogenetic study based on genetic sequences and sexual traits. Although a robust phylogeny could be not be resolved due to discordance of the different data sets, the discordance itself is quite interesting and is discussed. Insight into the biogeographic history based on genetic information and distributional data concludes this part. Finally, Chapter 6 begins with a complete literature review and the taxonomic history of the family and every species ever associated with it. This chapter also comprises a morphological study, which includes SEM images of all body parts of all species and a discussion of morphological characters. All 14 species currently assigned to Euryuridae are listed with complete synonymies, citations and diagnoses.