A revision ofDendromonocotyleHargis, 1955 (Monogenea: Monocotylidae) with a description of a new species fromPastinachus sephen(Forsskål) (Myliobatiformes: Dasyatididae) from the Great Barrier Reef, Australia

Abstract

The genus Dendromonocotyle contains seven previously described species: D. octodiscus Hargis, 1955; D. taeniurae Euzet and Maillard, 1967; D. kuhlii Young, 1967; D. cortesi Bravo-Hollis, 1969; D. akajeii Ho and Perkins, 1980; D. californica Olson and Jeffries, 1983; and D. centrourae Cheung and Whitaker, 1993. An eighth species, D. ardea sp. nov., is described from the dorsal body surface of the ray Pastinachus sephen (Forsskål) from Heron Island, Queensland, Australia. Dendromonocotyle ardea is distinguished from other species in the genus by the distinctive morphology of the terminal papillar sclerite, distal portion of the male copulatory organ and proximal portion of the vagina. An accessory chamber which may serve as a second seminal receptacle is also a differentiating character. Dendromonocotyle octodiscus, the type species of the genus, is redescribed and illustrated, and supplementary data and illustrations for features of the other species of the genus are provided. A key to the species of the genus is included. Hamuli are present in D. ardea and are recorded for the first time in D. akajeii and D. californica. The developmental sequence of the male copulatory organ in D. ardea from juvenile to adult is described. Close correspondence between the shape of the distal portion of the male copulatory organ and the proximal part of the vagina suggests that species recognition in this genus may conform to the lock-and-key hypothesis.