Ancyrocephalids (Monogenea) from Morone spp. (Percichthyidae) in North America, including redescriptions of Onchocleidus mimus Mueller, 1936 and O. interruptus Mizelle, 1936

Abstract

The ancyrocephalids (Monogenea) parasitizing the temperate basses (Percichthyidae) of North America are reviewed. Onchocleidus mimus Mueller, 1936 is redescribed from material found on the gills of Morone chrysops (white bass) taken in Ontario. Onchocleidus rogersi (Hanek and Fernando, 1972) Beverley-Burton, 1984 is declared a synonym of O. mimus. Onchocleidus interruptus Mizelle, 1936 is redescribed from paratype material (14 specimens) found on M. mississippiensis (yellow bass) taken in Illinois. Additional morphometric and morphologic data for O. chrysops (Mizelle and Klucka, 1953) Beverley-Burton, 1984 are provided. Cleidodiscus sp. of S. Tedla and C. H. Fernando and "Tetraonchinae" of C. J. Sindermann are considered to be referrable to the genus Onchocleidus sensu Beverley-Burton. Following a study of type specimens of Aristocleidus hastatus Mueller, 1936 from M. saxatilis (striped bass) taken in Florida, the genus and species are recognised as valid. However, there is need for a revision of the generic diagnosis when new material becomes available as the morphology of the male copulatory complex appears to be distinctive and of a "type" as yet undescribed. Urocleidus nactus Mayes and Johnson, 1975 found on M. americana (white perch) taken in coastal waters of North Carolina is transferred to Pterocleidus Mueller, 1937 as Pterocleidus nactus (Mayes and Johnson, 1975) n. comb. The possibility that ancyrocephalids found on M. americana taken in estuarine waters of the Hudson River by V. M. Liguori and identified as U. biramosus (Mueller, 1937) are conspecific with P. nactus is discussed. Ancyrocephalids possessing the spiral filament penis type occur almost exclusively on fishes of the Percoidae. Possible evolutionary pathways involving ancestral dactylogyridans (sensu Beverley-Burton) parasitizing estuarine Percichthyidae or freshwater Centrarchidae are presented with particular reference to the ancryrocephalids found on Morone spp.