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Taxonomy and Biology of benedeniine capsalid monogeneans

Abstract The Benedeniinae, the largest of nine capsalid subfamilies, includes genera with an aseptate, apapillate haptor and a pair of discrete testes. Eight of 13 nominal benedeniine genera, Benedenia Diesing, 1858 (the type genus); Allobenedenia Yamaguti, 1963; Allometabenedeniella Velasquez, 1982; Dioncopseudobenedenia Yamaguti, 1965; Lagenivaginopseudobenedenia Yamaguti, 1966; Oligoncobenedenia Yamaguti, 1965; Pseudallobenedenia Yamaguti, 1966 and Tareenia, Hussey, 1986 are revised using type material of most nominal species with observations for some species from new material. Allobenedenia and Allometabenedeniella are transferred to the Trochopodinae Price, 1936 emend. Sproston, 1946 because all valid species of both genera bear septa on the ventral haptor surface. Allobenedenia ishikawae (Goto, 1894) Yamaguti, 1963 is transferred to Benedenia because its haptor is aseptate. I recognize Menziesia Gibson, 1976, based on the form of the male copulatory organ and associated structures and include five species in it. Tareenia Hussey, 1986 is synonymised with Benedenia because characters used to differentiate the two genera do not indicate discontinuities at the generic level. Benedeniella Johnston, 1929, Calicobenedenia Kritsky and Fennessy, 1999 and Trimusculotrema Whittington and Barton, 1990 are considered to belong in Entobdellinae Bychowsky, 1957, pending further studies on that group. The anatomy of Calicobenedenia is outlined briefly; the other genera are not discussed here in detail. Lachishia n. g. is described, based on the structure of the male copulatory organ and a species is transferred to it from Dioncopseudobenedenia. I describe four new species of benedeniines from teleosts caught at Heron and Green Islands, Australia namely: Benedenia ernsti n. sp. from the gills of Symphorus nematophorus; Benedenia fieldsi n. sp. from the fins of Cephalopholis boenak, C. cyanostigma and C. miniatus; Benedenia haywardi n. sp. from the skin of S. nematophorus and Dioncopsudobenedenia ancoralis n. sp. from the gills of Siganus lineatus. Benedenia akaisaki Iwata, 1990 is synonymised with B. ovata (Goto, 1894) Johnston, 1929, B. kintoki Iwata, 1990 is synonymised with B. elongata (Yamaguti, 1968) Egorova, 1997, B. sargocentron Zhang, Yang and Liu, 2001 is synonymised with B. hawaiiensis Yamaguti, 1968 and Pseudallobenedenia arabica Timofeeva, 1995 is synonymised with P. opakapaka Yamaguti, 1966. Benedenia madai Ishii and Sawada, 1938, B. pagrosomi Ishii and Sawada, 1938 and Allobenedenia pedunculata Raju and Rao, 1980 are considered species inquirendae. I examined an outbreak in aquaculture of the pathogenic benedeniine, Neobenedenia melleni (MacCallum, 1927) Yamaguti, 1963 and report this species for the first time in Australia. I examined the pathogenesis caused by this parasite by histology of host tissue. Possible routes of introduction to the farm in question are investigated and studies are detailed that should be undertaken in Australia to manage future outbreaks of N. melleni. Capsalids usually colonise new hosts by an infective ciliated oncomiracidium. An experiment was conducted to ascertain whether cleaner fish Labroides dimidiatus could transfer adult skin-parasitic monogeneans from one host fish to another. I have shown that transmission of adult monogeneans between two individuals of Hemigymnus melapterus by cleaner fish can occur. In coral reef environments, frequent contact between unrelated hosts involved in cleaning interactions might create previously unsuspected evolutionary pressures. I discuss the implications of this discovery for host-specificity and lateral transmission of monogeneans. General biological studies of monogeneans are necessary to understand the evolution, pathology, epidemiology, phylogeny and taxonomy of these parasites. My study provides a taxonomic system which, when applied to other capsalid subfamilies, should help prevent errors and create a clear system of classification for the entire family.

Identiferoai:union.ndltd.org:ADTP/291158
CreatorsDeveney, Marty R.
Source SetsAustraliasian Digital Theses Program
Detected LanguageEnglish

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