The genus Acanthobothrium (Cestoda : Tetraphyllidea : Onchobothriidae) parasitic in Australian elasmobranch fishes

Abstract

The onchobothriid tetraphyllidean cestode genus Acanthobothrium van Beneden, 1849, parasitic in the spiral intestine of elasmobranch fishes, was investigated in the Australian region. Thirty-three species are recognised, including 27 that are new. Diagnoses compare the morphological taxonomic characters of all congeners. New species are: Acanthobothrium adlardi; A. angelae; A. arlenae; A. bartonae; A. blairi; A. brayi; A. cannoni; A. chisholmae; A. clarkeae; A. cribbi; A. edmondsi; A. gasseri; A. gibsoni; A. gloveri; A. jonesi; A. lasti; A. laurenbrownae; A. martini; A. mooreae; A. ocallaghani; A. odonoghuei; A. pichelinae; A. robertsoni; A. rohdei; A. stevensi; A. thomasae; and A. walkeri. Additional morphological data are provided for A. australe Robinson, 1965, A. pearsoni Williams, 1962, A. heterodonti Drummond, 1937 and A. urolophi Schmidt, 1973, reported previously from Australia. Acanthobothrium rhynchobatidis Subhapradha, 1955 and A. semnovesiculum Verma, 1928 are reported from Australia for the first time and are redescribed. Additional morphological details are provided for A. ijimae Yoshida, 1917 and A. grandiceps Yamaguti, 1952. Acanthobothrium wedli Robinson, 1959 is redescribed from the type host from New Zealand waters and considered a sister species of A. blairi from Tasmania. Seven new host genera for Acanthobothrium are reported: Hypnos Duméril, 1852 (Hypnidae); Pristiophorus MÜller & Henle, 1837 (Pristiophoridae); Sutorectus Whitley, 1939 (Orectolobidae); Aptychotrema Norman, 1926 and Trygonorrhina MÜller & Henle, 1838 (Rhinobatidae); Parascyllium Gill, 1862 (Parascylliidae); and Aetomylaeus Garman, 1908 (Myliobatididae). Species of Acanthobothrium are reported from the families Hypnidae, Pristiophoridae and Parascylliidae for the first time. New host species for Acanthobothrium are: Pristiophorus cirratus (Latham, 1794); Parascyllium ferrugineum McCulloch, 1911; Sutorectus tentaculatus (Peters, 1865); Aptychotrema vincentiana (Haacke, 1885); Trygonorrhina fasciata MÜller & Henle, 1841; Raja whitleyi Iredale, 1938; Raja cerva Whitley, 1939; Hypnos monopterygium (Shaw & Nodder, 1795); Dasyatis annotata Last, 1987; Urolophus cruciatus (Lacépède, 1804); Urolophus expansus McCulloch, 1916; Urolophus lobatus McKay, 1966; Urolophus paucimaculatus Dixon, 1969; Gymnura australis (Ramsay & Ogilby, 1886); Aetomylaeus nicofii (Schneider, 1801); and Myliobatis australis Macleay, 1881 (Myliobatididae). New host records for Australia include the above 16 elasmobranch species and the following three host species also known to harbour Acanthobothrium in other geographic localities: Rhynchobatis djiddensis (Forsskål, 1775) (Rhynchobatidae); Himantura uarnak (Forsskål, 1775); and Pastinachus sephen (Forsskål, 1775) (Dasyatidae). Four additional records for hosts previously reported for Acanthobothrium from Australian waters are Squalus megalops (Macleay, 1881) (Squalidae), Heterodontus portusjacksoni (Meyer, 1793) (Heterodontidae), Orectolobus maculatus (Bonnaterre, 1788) (Orectolobidae) and Trygonoptera ‘testacea’ MÜller & Henle, 1841 (Urolophidae). An emended diagnosis of the genus, key to Australian species, host-parasite checklist, phylogenetic analysis of the Australian species and an updated world list of all species of Acanthobothrium are provided.

Morphology of the blood cells from three species of wobbegong sharks (Orectolobus species) on the east coast of New South Wales

“…It is also expected that wild populations of fish including sharks would have a higher number of parasites than species living in captivity due to implemented parasite control measures. Campbell and Beveridge [2002] have recently reviewed the Acanthobothrium of Australian elasmobranchs and included some species from the spotted wobbegong shark, but to date, no other parasites have been described from the other two species of shark in this study. Animals in this study did have some unidentified intracellular parasites in some erythrocytes.…”

A new tetraphyllidean genus and species, Caulopatera pagei n. g., n. sp. (Tetraphyllidea: Phyllobothriidae), from the grey carpetshark Chiloscyllium punctatum Müller & Henle (Orectolobiformes: Hemiscylliidae)

“…Although the tetraphyllidean fauna of some of these orectolobiform species has been the focus of several studies (e.g. Butler, 1987;Campbell & Beveridge, 2002;Caira et al, 2004;Ruhnke et al, 2006a;Caira et al, 2007), more comprehensive sampling of these often endemic Australian sharks, as well as more extensive sampling of C. punctatum from regions along Australia's northern coastline, may lead to the discovery of more species of Caulopatera and expand our understanding of the new genus.…”

Acanthobothrium Blanchard, 1948 from the northwest Atlantic and their phylogenetic relationships with freshwater lineages

“…Acanthobothrium is distributed worldwide and represent the most diverse genus of the Onchobotriidae, representing almost 76% of the species in the family Campbell & Beveridge, 2002;Machado & Marques, 2012), with more than 195 nominal species described (Caira et al, -2018. Members of this genus parasitize several species of Elasmobranchii: rays, skates (Myliobatiformes, Rajiformes, Rhinopristiformes and Torpediniformres) and sharks (Charchaniformes, Orectolobiformes, Heterodontiformes and Squaliformes) .…”

“…Each bothridia exhibits a pair of bipronged hooks, and an apical muscular pad bearing an apical sucker (Campbell & Beveridge, 2002;Machado & Marques, 2012).…”

“…The degree of host specificity of cestodes of elasmobranchs observed in South America freshwater (SAFW) and marine environments are remarkably different. In marine stingrays, the infection by Acanthobothrium is characterized by a pattern of one parasite species in a single or few hosts -with few exceptions (Campbell & Beveridge, 2002;Fyler, 2009). Whereas in SAFW, the same Acanthobothrium species can be distributed in more than 15 different hosts (Cardoso Jr., 2010).…”