A Microsporidian Infection in Phoronids (Phylum Phoronida): Microsporidium phoronidi n. sp. from a Phoronis embryolabi
Microsporidia-like spores (2.0–3.0 9 1.3–1.5 lm) were discovered upon examination
of histological sections taken from Phoronis embryolabi Temereva,
Chichvarkhin 2017 found inhabiting burrows of shrimps Nihonotrypeae japonica
(Decapoda, Callianassidae) from the Sea of Japan, Russia. Ultrastructural
examination of spores revealed one nucleus and a uniform polar filament of 7–
11 coils. Representatives of the phylum Phoronida have never been recorded
as hosts of microsporidia. Parasites developed in vasoperitoneal tissue and
caused formation of multinucleate syncytia. Basing on unique host and fine
morphology, we assign the novel finding to Microsporidium phoronidi n. sp.
and place provisionally in the collective genus Microsporidium.