Microsporidian genus Berwaldia (Opisthosporidia, Microsporidia), infecting daphnids (Crustacea, Branchiopoda): Biology, structure, molecular phylogeny and description of two new species.

Structural, molecular and life cycle data are presented for two microsporidian species of the genus Berwaldia: B. singularis Larsson, 1981 (type species of the genus) and B. schaefernai Vávra and Larsson, 1994, parasites of Daphnia pulex Leydig, 1860 and Daphnia galeata Sars, 1863, respectively. Analysis of the SSU rDNA gene confirmed the species status of both species and showed that the GenBank sequence data submitted previously in GenBank for the genus Berwaldia, are from microsporidia that are not Berwaldia. Correct SSU rDNA gene sequences for B. schaefernai and B. singularis are now deposited in GenBank. The life cycle of these two species appears incomplete as the spores collected from their respective infected hosts will not infect the same host when fed per os. B. schaefernai appears as a frequent parasite of Daphnia longispina/galeata complex daphnids, influencing the behaviour of the infected host. In addition, two new species, of Berwaldia, one infecting fat body tissues of Daphnia longispina/galeata complex, and the other, infecting hypodermis and fat cells of Simocephalus vetulus (O. F. Müller, 1776) are described.