A NEW MICROSPORIDIUM, NOSEMA-CRISTATELLAE N-SP IN THE BRYOZOAN-CRISTATELLA MUCEDO (BRYOZOA, PHYLACTOLAEMATA)

A microsporidian infecting cells of the body wall of the phylactolaema te bryozoan Cristatella mucedo is described, All stages of the parasit e are diplokaryotic and lie in direct contact with the host cell cytop lasm. Sporogony is probably disporoblastic, Spores measure 7.5 x 5.1 m u m and have 22-32 coils of the polar tube arranged in several rows an d a bell-like polaroplast of compact membranes. The parasite is assign ed to the genus Nosema as a new species, Nosema cristatellae. It is di fferentiated from the previously described parasites of Alcyonella (=P lumatella) fungosa (Bryozoa), named Myxosporidium bryozoides and Nosem a bryozoides, by spore characters and tissue specificity. Although it was found in a different species of bryozoan, it is not known whether N. cristatellae is infective to P. fungosa. (C) 1997 Academic Press.