During a survey ofmyxozoan parasite

During a survey ofmyxozoan parasites of common
carp Cyprinus carpio in Honghu Lake, Hubei Province,
China, a parasite was collected that was identified as
Myxobolus dispar based on an earlier description from
China. However, the small subunit ribosomal DNA of this
species shared only 90 % similarity with M. dispar, instead
matching M. musseliusae with 100 % identity. To resolve this
apparent taxonomic conflict, the validity of M. dispar reported
from China was investigated. The species encountered here
and in the earlier report from China both bear spores that are
notably smaller than those of M. dispar in Europe. In the
present study, a mucous envelope was adhered to the posterior
of many fresh spores and was observed to expand and
surround the spore. This structure has never been reported
from fresh spores of M. dispar. Histology showed extravascular
plasmodia in the gill filaments in close contact with the
cartilaginous ray of the filament, which contrasts with the
plasmodia of M. dispar which develop in the arteries of the
gill filaments. Phylogenetically, the current species is distinct
from M. dispar, instead forming a sister group with M. musseliusae.
The data presented here allow us to conclude that the
species isolated is M. musseliusae and that prior reports of M.
dispar in China are unsubstantiated.