During investigations of young-of-the year smallmouth bass (Micropterus dolomieu) mortalities in the Susquehanna River, Pennsylvania, U.S.A. and affected tributaries, raised areas were noted in the muscle in the vicinity of the caudal peduncle. The raised areas were caused by plasmodia of a myxozoan parasite. Spores found within plasmodia were similar to those of Myxobolus inornatus previously described from the caudal peduncle of fingerling largemouth bass (Micropterus salmoides) in Montana. Here, M. inornatus is redescribed based on histologic comparisons and spore measurements. The addition of spore photographs, line drawings, a voucher specimen, and partial small-subunit ribosomal (rSSU) DNA gene sequence are new in this study. This is also the first description of M. inornatus from smallmouth bass. The plasmodia of M. inornatus were grossly observed at the base of the caudal and dorsal fins and were 280.3 ± 33.5 (range 77.1–920.3) μm long and 320.6 ± 41.0 (range 74.85–898.4) μm wide. In some instances, plasmodia of M. inornatus were large enough to rupture the epidermis or were associated with misaligned vertebrae. The slightly pyriform spores were 11.3 ± 0.2 (range 8.6-17.4) μm in length and 8.6 ± 0.2 (range 7.1–13.7) μm wide with an iodinophilous vacuole and a sutural ridge with 8 to 10 sutural folds. The SSU rDNA gene sequence places M. inornatus in a sister group with Myxobolus osburni.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 98 • No. 6