부산대학교 도서관

Ciliates of the order Mobilida are obligate symbionts of a broad spectrum of invertebrates and vertebrates. Rigid structures of their adhesive disc, which serves for attachment to the host, are traditionally used for species identification. Using a holistic morpho-evo-eco approach, we attempted to address whether (1) also host organisms and their life histories represent important features in the mobilid taxonomy, (2) morphological similarities estimated from characters of the adhesive disc correspond to genetic similarities, and (3) which molecular markers are reliable DNA barcodes in the mobilid taxonomy. Multidimensional analyses revealed that morphometric data of the adhesive disc are not sufficient to delimit closely related species that are, however, phylogenetically and ecologically distinct. Out of the seven tested molecular markers, only the mitochondrial 16S and COI genes were found to be reliable DNA barcodes allowing unambiguous delimitation of also closely related species. Stochastic mapping suggested that higher taxonomic groups and life histories of host organisms also represent important extrinsic characteristics of mobilid species, especially when they are put in the phylogenetic context. Links of ciliates with freshwater fishes and with marine mollusks were recognized as statistically significant correlates during the mobilid evolution. The new standard in the inventory of the diversity of mobilid ciliates is exemplified by a holistic characterization of two species, Trichodina unionis and T. baltica, associated with aquatic mollusks. [ABSTRACT FROM AUTHOR]