Two new species of Cacatuocotyle (Monopisthocotyla: Dactylogyridae) from Neotropical characiform fishes.

Two new species of Cacatuocotyle are described from characiform fishes from the upper Paraná River basin, Brazil: Cacatuocotyle fluvialis n. sp. from the skin of Psalidodon bockmanni (Characiformes, Acestrorhamphidae) and Cacatuocotyle calicata n. sp. from the gills of Bryconamericus iheringii (Characiformes, Stevardiidae). Cacatuocotyle fluvialis n. sp. can be distinguished from most of its congeners mainly by the morphology of the male copulatory organ (MCO), with clockwise rings, accessory piece, and sclerotized structures of the haptor. Cacatuocotyle calicata n. sp. differs from other congeners mainly by the shape of the bar (which is broadly V-shaped with anterior and posterior margins slightly irregular, and the median region wider than extremities); the size of anchors (which is the smallest among species of Cacatuocotyle), and the morphology of accessory piece. Molecular data based on mitochondrial (mtCOI) and ribosomal (28S rDNA) markers were obtained for the new species described, and the phylogenetic analysis revealed that species of Cacatuocotyle compose a monophyletic group which is related and sister to Diaphorocleidus spp., also parasites of characiforms.