Myxobolus ictiobus n. sp. and Myxobolus minutus n. sp. (Cnidaria: Myxobolidae) from the gills of the smallmouth buffalo Ictiobus bubalus Rafinesque (Cypriniformes: Castostomidae)

Authors: ROSSER, THOMAS - Mississippi State University; GRIFFIN, MATT - Mississippi State University; Quiniou, Sylvie; ALBERSON, NEELY - Mississippi State University; WOODYARD, ETHAN - Mississippi State University; MISCHKE, CHARLES - Mississippi State University; GREENWAY, TERRENCE - Mississippi State University; WISE, DAVID - Mississippi State University; POTE, LINDA - Mississippi State University

Submitted to: Systematic Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/21/2016
Publication Date: 7/1/2016
Citation: Rosser, T.G., Griffin, M.J., Quiniou, S., Alberson, N.R., Woodyard, E.T., Mischke, C.C., Greenway, T.E., Wise, D.J., Pote, L.M. 2016. Myxobolus ictiobus n. sp. and Myxobolus minutus n. sp. (Cnidaria: Myxobolidae) from the gills of the smallmouth buffalo Ictiobus bubalus Rafinesque (Cypriniformes: Castostomidae). Systematic Parasitology. 93(6):565-574.

Interpretive Summary: Smallmouth buffalo are occasionally grown in pond aquaculture and have been reported to suffer from Myxobolus parasite infections. A group of Smallmouth buffalo co-cultured with catfish were examined for the presence of parasitic infection. This survey identified two previously unknown species of Myxobolus parasites. The identification was done using both morphologic descriptions and DNA analysis. DNA analysis places these parasites within a group of parasites infecting sucker type fishes. Therefore those parasites are unlikely to infect catfish and pose little risk to the catfish aquaculture.

Technical Abstract: The smallmouth buffalo Ictiobus bubalus Rafinesque (Catostomidae) is native to North American waterways and occasionally grown in pond aquaculture. Species of Myxobolus Bütschli, 1882 have been reported from the gills, integument, and intestinal tract of buffalo fish, although there is ambiguity in some host records. In the summer of 2013, thirteen adult smallmouth buffalo were seined from a 0.1-acre (0.04-hectare) experimental research pond at the Thad Cochran National Warmwater Aquaculture Center in Stoneville, Mississippi, USA, and examined for the presence of parasitic infection. Two previously unknown species of Myxobolus were observed parasitising the gills. Plasmodia of the two species differed from each other in both size and shape. Morphologically the two species were distinct from one another and from other Myxobolus spp. previously reported from buffalo fish. Myxospores of Myxobolus ictiobus n. sp. were spherical and measured 12.7–14.5 (13.9 ± 0.4) µm in length and 10.7–13.6 (12.5 ± 0.7) µm in width with a thickness of 10.3–14.8 (12.6 ± 2.3) µm. Polar capsules measured 5.6–7.4 (6.6 ± 0.4) µm in length and 3.7–4.9 (4.5 ± 0.8) µm in width and each contained a coiled polar filament with 5–6 turns. Myxospores of Myxobolus minutus n. sp. were circular in shape and measured 7.4–9.6 (8.6 ± 0.7) µm in length and 7.5–9.9 (8.8 ± 0.7) µm in width with a thickness of 6.5–7.3 (6.7 ± 0.3) µm. Polar capsules measured 3.6–4.9 (4.3 ± 0.3) µm in length and 2.8–3.8 (3.3 ± 0.3) µm and each contained a coiled polar filament with 5–6 turns. Supplemental 18S rRNA gene sequencing identified unique sequences for each isolate. Phylogenetic analysis of 18S rRNA sequences demonstrated a strong clustering of both isolates with other species of Myxobolus from cypriniform fish.