Date of Award
Program or Major
Doctor of Philosophy
Marianne K Litvaitis
In a first survey of the Colombian polyclad fauna, a total of 25 species were collected from the rocky littoral of the Tayrona National Park, Santa Marta, Colombia and deposited at the Museo de Historia Natural Marina del INVEMAR. Six species represented first records for Caribbean region. Furthermore, a new combination Phrikoceros mopsus nov. comb, was proposed, and a possible new species of Pleioplana Faubel, 1983 was found. In addition, a new polyclad family Anocellidae was erected and four deep-sea species were described; two species from the North Pacific Ocean, Anocellidus profundus gen. nov. sp. nov. and Oligocladus voightae sp. nov., and two from the continental slope of the Gulf of Mexico, Oligocladus bathymodiensis sp. nov. and Didangia carneyi sp. nov. All except D. carneyi, were found in association with bivalves. The type material was deposited at the Field Museum of Natural History, Chicago, Illinois, USA. All taxonomic work was based on major external features and serial sagittal sections of the reproductive system. Finally, the central nervous systems (CNS) of 12 species of polyclad flatworms belonging to 11 families were examined using traditional light microscopic techniques. Even though some morphological features of the CNS probably were related to the body shape and behavior of the species, three categories could be established. These categories were based on the presence and development of globuli cell masses, the cross-sectional shape of the main nerve cords, and the tissue type surrounding the nerve cords. Well-developed globuli cell masses characterize all acotylean species examined. Furthermore, the cotylean Pericelis cata also had well-developed globuli cell masses, providing additional evidence of the close phylogenetic relationship of Pericelidae with the Acotylea. Cotylean polyclads on the other hand, exhibit only weakly developed globuli cell masses. Unique features of the CNS were found in Boninia divae which represent autapomorphies for the family and which can be linked to the behavior and body shape of this taxon. The presence of external globuli cells masses in some polyclads, forming structures similar to arthopod mushroom bodies, may be an indication of an early evolutionary adaptation.
Quiroga, Sigmer Y., "Systematics and taxonomy of polyclad flatworms with a special emphasis on the morphology of the nervous system" (2008). Doctoral Dissertations. 449.