Pilar A. Haye

Date of Award

12-2002

Level of Access Assigned by Author

Open-Access Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Biological Sciences

Advisor

Irv Kornfield

Second Committee Member

Leslie Watling

Third Committee Member

Christopher Campbell

Abstract

Cumaceans are small benthic crustaceans. They have a marine cosmopolitan distribution with diversity increasing with depth. There are approximately 1,400 described species of cumaceans. Despite the fact that they offer a good model for the study of morphological evolution and biogeography, the studies on the Order Cumacea are almost restricted to work at the alpha taxonomy level. This thesis contributes to the systematics of Cumacea. The phylogenetic relationships within the Cumacea were studied using newly obtained partial amino acid sequences from the mitochondria1 gene Cytochrome Oxidase I. Among other findings, phylogenetic analyses revealed that the families Bodotriidae, Leuconidae, and Nannastacidae, characterized by the presence of a pleotelson (telson fused to last abdominal segment), form a monophyletic and derived clade. The gene tree topology suggests that some characters traditionally used in cumacean diagnoses represent homoplasies. The cumacean family Bodotriidae is divided into three subfamilies and 34 genera with over 350 species, all of which were morphologically analyzed for 114 variable characters. Two main accomplishments were a result of this study. First, the phylogenetic relationships of the subfamilies and genera within the family were studied. The subfamily Mancocumatinae failed to resolve as a monophyletic group, the subfamily Vaunthompsoniinae are basal bodotriids, and the subfamily Bodotriinae is the most derived clade. A Tethyan origin for the bodotriid fauna is suggested, with radiation along the Atlantic Ocean during the Cretaceous. Phylogenetic and character evolution analyses support several changes to the classification of Bodotriidae. For example, the subfamily Mancocumatinae should be incorporated into the subfamily Vaunthornpsoniinae, the genus Coricuma should be incorporated into the Bodotriinae, and the species of the genera Heternma, Mossambicuma, Pseudocydaspis, should be incorporated into the genera Cumopsis, Eocuma and Cydaspis, respectively. Second, a comprehensive morphological work on the Family Bodotriidae was completed incorporating the suggested changes in the taxonomy . The generic review includes a dichotomous key and rediagnosis of each of the genera of the Family. A new species of Austrocuma from the eastern coast of lndii is described. Among other characters, the uniqueness of this species relies on the presence of onty four pleopods on the males.

Download

Share