Description of Heteroplectanum oliveri sp. n.(Monogenea: Diplectanidae) and comments on the helminth fauna of Kyphosus elegans (Perciformes: Kyphosidae) from Chamela Bay, México - Léon-Regagnon, V.; Pérez-Ponce de León, G.; Garcia-Prieto, L. (Journal of the Helminthological Society of Washington, 1997)