A new species of Entobdella Blainville in Lamarck, 1818 (Monogenea: Capsalidae: Entobdellinae) from the Greenland halibut, Reinhardtius hippoglossoides

A previously undescribed species of Entobdella is reported from the skin of the Greenland halibut, Reinhardtius hippoglossoides (Pleuronectiformes, Pleuronectidae). Entobdella whittingtoni sp. nov. differs from other species of Entobdella, including skin parasites of the related pleuronectids Hippoglossus hippoglossus (Atlantic halibut) and H. stenolepis (Pacific halibut), in lacking papillae on the ventral surface of the haptor. Other characteristics of E. whittingtoni are as follows: the absence of vitelline follicles lateral to the pharynx thereby exposing gut caeca in this region of whole mounts; the presence of a circular feature of unknown function, resembling a rosette in sections, attached to the wall of the internal male accessory reservoir; the lack of eyes. Papillae are also absent from the ventral surface of the haptor of the gill-parasitic entobdelline Branchobdella pugetensis, a gill parasite of the pleuronectid Atheresthes stomias. This raises the question as to whether this gill parasite has evolved from a skin-parasitic ancestor similar to E. whittingtoni. An answer to this question requires a more detailed study of the male reproductive apparatus of B. pugetensis and the use of molecular techniques to explore the relationship between B. pugetensis and E. whittingtoni.

Revision of Allobenedenia Yamaguti, 1963 (Monogenoidea: Capsalidae) with the description of A. zhangi n. sp. from Epinephelus fasciatus (Teleostei: Serranidae) in the South China Sea

Allobenedenia Yamaguti, 1963 is revised to include capsalid species with five radial septa in the haptor. Megalocotyloides Bychowsky & Nagibina, 1967 and Allosprostonia Lawler & Hargis, 1968 are considered junior synonyms of Allobenedenia. Eight described species comprise the genus: A. convoluta (Yamaguti, 1937) Yamaguti, 1963 (type-species), A. epinepheli (Bychowsky & Nagibina, 1967) n. comb., A. patagonica (Evdokimova, 1969) n. comb., A. pedunculata Raju & Rao, 1980, A. pseudomarginata (Bravo-Hollis, 1958) n. comb., A. sebastodi (Egorova, 1994) n. comb., A. yamagutii (Egorova, 1994) n. comb. and A. zhangi n. sp. A. ishikawae (Goto, 1894) Yamaguti, 1963 is considered a species inquirenda; Megalocotyloides hongkongensis Wu, Lu & Woo, 2002 is placed in synonymy with A. yamagutii; M. grandiloba (Paperna & Kohn, 1964) Egorova & Aleshkina, 1984 is provisionally returned to Megalocotyle as M. grandiloba Paperna & Kohn, 1964; and specimens identified as M. grandiloba from Serranus cabrilla (Serranidae) by Buhrnheim et al. (1973) are considered an undescribed species of Allobenedenia. A. zhangi n. sp. is described from the external surface of Epinephelus fasciatus (Serranidae) of Allobenedenia. A. zhangi n. sp. is described from the external surface of Epinephelus fasciatus (Serranidae) in the South China Sea and is characterised by having an elongtate proximally uncoiled male copulatory organ extending to near the level of the anterior margin of the ovary, a large prostatic reservoir apparently external to the male copulatory canal, and a submedial protuberance on the dorsal surface of the accessory sclerite of the haptor.

The capsalidae (Monogenea: Monopisthocotylea): a review of diversity, classification and phylogeny with a note about species complexes

The Capsalidae are monogeneans parasitizing 'skin', fins and gills of marine fishes. Some capsalids are pathogenic to cultivated fish and a few have caused epizootic events. It is a cosmopolitan family with broad host associations (elasmobranchs and teleosts, including sturgeons). Approximately 200 capsalid species are placed in nine subfamilies and 44-46 genera, some of which are well known (Benedenia, Capsala, Entobdella, Neobenedenia). Sturgeons host two capsalid species (Nitzschiinae) and 15 species in five genera are reliably reported from elasmobranchs. The combination of ancient (shark, ray, sturgeon) and modem (teleost) host fish lineages indicates that capsalid evolution is likely a blend of coevolution and host-switching, but a family phylogeny has been lacking due to deficient knowledge about homologies. The current phenetic subfamilial classification is discussed in detail using a preliminary phylogeny generated from large subunit ribosomal DNA sequence data from representatives of five subfamilies. Monophyly of the Capsalidae is supported by possession of accessory sclerites. Hypotheses are proposed for the possible radiation of capsalids. A suggestion that Neobenedenia melleni, a pathogenic species atypical due to its broad host-specificity (>100 host teleost species from >30 families in five orders), may be a complex of species is supported from genetic evidence. This may explain peculiarities in biology, taxonomy, host associations and geographic distribution of N. 'melleni' and has implications for fish health. Holistic studies using live and preserved larval and adult capsalid specimens and material for genetic analysis are emphasised to further determine identity, phylogeny and details of biology, especially for pathogenic species.

Glands associated with the anterior adhesive areas of the monogeneans, Entobdella sp. and Entobdella australis (Capsalidae) from the skin of Himantura fai and Taeniura lymma (Dasyatididae)

Using scanning and transmission electron microscopy, investigations were carried out on the anterior adhesive areas of Entobdella sp. from the skin of Himantura fai and Entobdella australis from the skin of Taeniura lymma at Heron Island, Australia. All studies were of parasites detached from either host tissue or a substrate. Both species of monogeneans have two characteristic anteroventral adhesive pads, one on either side of the head, subdivided to a "diadem". Two types of gland cells are associated with the anterior adhesive areas in both species and each cell type produces a different secretion: a rod-shaped secretion and a smaller, roughly spherical secretion. Each secretion type differs in electron-density, with those putatively in the process of formation being less electron-dense. Both types of secretory bodies are membrane-bound. Microtubules are evident around forming rod-shaped bodies. The bounding membranes of the rods of both species show a periodic banding of approximately 12 nm. Both types of secretion are present at the surface of the adhesive pads in specimens of Entobdella sp. fixed when detached from the host. The secretory bodies observed in Entobdella sp. and E. australis from rays show some differences to those reported from Entobdella soleae, a parasite of a flatfish teleost. Other ultrastructural differences also exist. We conclude that the types of adhesive secretory bodies may remain constant within genera providing the hosts are similar.