Molecular systematics and zoogeography of the "glacial relict" element

Doctoral thesis, University of Helsinki (1994). 16 pp. + 6 articles. ISBN 952-90-5483-1 The "glacial relict" zoogeographical element comprises a diverse group of crustacean species with largely coincident northern lacustrine distributions. They mostly represent genera which also have coincident overall distributions, encompassing taxa (i) in circumarctic coastal waters, (ii) in boreal and subarctic lakes of Eurasia and North America, and (iii) in the Caspian Sea. It has long been debated whether the evolution of the non-marine taxa from marine ancestors took place relatively recently in connection with Pleistocene glacial events, or much earlier in the Tertiary. In this study, inter- and intraspecific molecular variation (allozymes) was used to elucidate the phylogeny and zoogeographical history of the "relict" crustacean genera Mysis and Pontoporeia (sensu lato) and their acanthocephalan parasites in Echinorhynchus (sensu /ato).