Meeting Abstract
P1.129 Jan. 4 Phylogenetic Relationships among Unionicola Mussel-Mites: Inferences from Morphological and Molecular Characters EDWARDS, D.D.*; ERNSTING, B.R.; VIDRINE, M.F.; Univ. of Evansville; Univ. of Louisiana, Eunice de3@evansville.edu
North American water mites of the genus Unionicola commonly occur in parasitic association with freshwater mussels, living on the gills or mantle and foot of their hosts. Although the taxonomy of theses mites has been reasonably documented, phylogenetic relationships among members of the group are less well known. This study uses morphological characters and sequence data of mitochondrial COI gene (694 bp) to reconstruct evolutionary relationships among subgenera of Unionicola from North America that parasitize freshwater mussels. Maximum parsimony analysis of 29 morphological characters yielded a single tree with high bootstrap support. The topology of the tree indicated 2 major clades, with subgenera that parasitize a host�s mantle tissues forming one clade and subgenera that infest a host�s gills forming the other. The phylogeny of these mites based on COI sequence data was incongruent with the morphological tree, with two subgenera of mantle-mites being incorporated into a clade containing gill mite subgenera. Combined parsimony analysis of the morphological and molecular data yielded a tree with the same topology as the tree derived from sequence data alone. Although the gene tree and combined tree raise questions about the diversification of parasitic lifestyles (gill vs. mantle parasites) among Unionicola mussel-mites, the typology of these trees are open to question given that most branches for both trees were not well supported in bootstrap analyses. The high bootstrap support for the morphological tree, in conjunction with incongruencies between the morphological and molecular trees and the lack of support for the molecular and combined trees suggests that molecular data from the additional mitochondrial and nuclear loci may be required when using molecular character information to resolve evolutionary relationships among these mites.
