MYXOZOANS (CNIDARIA: MYXOSPOREA: MYXIDIIDAE) IDENTIFIED FROM THE GALLBLADDER OF FRECKLED MADTOM, NOTURUS NOCTURNUS (SILURIFORMES: ICTALURIDAE), FROM THE OUACHITA RIVER DRAINAGE OF SOUTHERN ARKANSAS.

Abstract

During August 2021 and again in July 2022 and July 2023, 4 freckled madtoms, Noturus nocturnus, were collected from a creek in Columbia County, Arkansas (Ouachita River drainage), and their gills, gallbladder, fins, integument, musculature, and other major organs were examined for myxozoans. The gallbladder of 1 (25%) was infected with apparently novel myxozoans. Qualitative and quantitative morphological data were from preserved formalin-fixed myxospores. Molecular data include 2,059 bp (for a Myxidium sp.) and 951 bp (for an unobserved Myxozoa sp.) sequences of the partial small subunit (SSU) ribosomal RNA gene. Phylogenetic analysis placed the Myxidium sp. among a clade of myxozoans that infect fish from the southern portion of North America. These represent the first myxozoans reported from the gallbladder of madtoms.