Five New Species of Acanthobothrium (Tetraphyllidea: Onchobothriidae) From the Freshwater Stingray Himantura Chaophraya (Batoidea: Dasyatidae) in Malaysian Borneo

Abstract

Five new species of Acanthobothrium (Tetraphyllidea: Onchobothriidae) are described from the spiral intestine of the Freshwater whipray, Himantura chaophraya, in the Kinabatangan River in Malaysian Borneo. Based on criteria set forth in a previous categorization scheme for species of Acanthobothrium, these consist of 3 Category 1 species, Acanthobothrium asnihae n. sp., Acanthobothrium saliki n. sp., and Acanthobothrium zainali n. sp.; a Category 8 species, Acanthobothrium etini n. sp.; and a Category 2 species, Acanthobothrium masnihae n. sp.. Acanthobothrium asnihae n. sp. differs from all Category 1 species in its possession of a horizontal band of weak musculature that divides the posterior loculus in half. Among Category 1 species, A. saliki n. sp. differs from all but Acanthobothrium southwelli in its possession of postovarian testes. It differs from A. southwelli in its possession of fewer testes and a greater number of proglottids. Acanthobothrium zainali n. sp. differs from the 25 other Category 1 species in a combination of overall size, muscular pad and hook shape, arrangement and number of testes, ovary configuration in cross section, position of ovarian isthmus, and genital pore position. Acanthobothrium etini n. sp. is distinguished from all 5 other Category 8 species in its lack of testes from the proglottid antiporal and postporal regions and in testis number. Acanthobothrium masnihae n. sp. differs from the 35 other Category 2 species in its possession of fewer testes, postporal testes, or a greater number of proglottids. A key to Acanthobothrium species parasitizing H. chayophraya is presented. This represents the first report of Acanthobothrium from freshwater stingrays belonging to a family other than the Potamotrygonidae.

Five new species of Acanthobothrium (Cestoda: Tetraphyllidea) from an unusual species of Himantura (Rajiformes: Dasyatidae) from northern Australia

“…At this point, 30 category 1 species are recognized (i.e., the 4 species described by Reyda and Caira [2006] and the 25 listed in their table 2, and A. marymichaelorum Twohig, Caira et Fyler, 2008). Acanthobothrium oceanharvestae conspicuously differs from A. foulki Reyda et Caira, 2006, A. larsoni Reyda et Caira, 2006, A. marymichaelorum, A. saliki Fyler et Caira, 2006and A. southwelli Subhapradha, 1955 in its lack of post-ovarian testes. It differs from A. asnihae Fyler et Caira, 2006 andA.…”

“…For the purposes of phylogenetic analyses, molecular data were generated for 2 specimens of each of the 5 new species of Acanthobothrium and also, for comparative purposes, for 2 specimens of Acanthobothrium masnihae Fyler et Caira, 2006 from the freshwater whipray, Himantura polylepis (Bleeker) (as Himantura chaophraya Monkolprasit et Roberts) from Borneo and for 2 specimens of an undescribed species of Acanthobothrium from the Tubemouth whipray, Himantura lobistoma Manjaji-Matsumoto et Last from Borneo. Also included in these analyses were 2 previously sequenced species of Acanthobothrium for which hologenophores and 28S rDNA data were available from GenBank: Acanthobothrium parviuncinatum Young, 1954 With respect to the selection of outgroups, the position of the genus Acanthobothrium within the larger framework of tetraphyllidean cestodes is unclear.…”

“…The tetraphyllidean genus Acanthobothrium van Beneden, 1850 is both a ubiquitous and conspicuous component of the cestode fauna of species of the Indo-Pacific stingray genus Himantura Müller et Henle examined to date (e.g., Srivastav and Capoor 1980, Campbell and Beveridge 2002, Fyler and Caira 2006, Reyda and Caira 2006, Twohig et al 2008). In such systems, Acanthobothrium species appear to exhibit oioxenous specificity for their stingray hosts.…”

“…In such systems, Acanthobothrium species appear to exhibit oioxenous specificity for their stingray hosts. In addition, it is not uncommon to find multiple members of the genus parasitizing a single species of Himantura (see Campbell and Beveridge 2002, Fyler and Caira 2006, Reyda and Caira 2006. The opportunity for JNC and KJ to spend time on a commercial trawling vessel working in the Arafura Sea off northern Australia, provided access to some of the larger species of batoids not yet examined for cestodes and that would have been difficult to obtain otherwise.…”

Taxonomia das linhagens de Acanthobothrium van Beneden, 1850 (Eucestoda: Tetraphyllidea) parasitas de Potamotrygonidae (Chondrichthyes: Myliobatiformes)

“…Testículos com 30120 (73,47 ± 17,40, n=75) de diâmetro, 4375 (58 ± 6, n=192) Acanthobothrium descritas (Southwell et al, 1912;Southwell, 1925;Yamaguti, 1934Yamaguti, , 1952Goldstein, 1964;Williams, 1969;Campbell & Beveridge, 2002;Fyler & Caira, 2006. Nesses estudos, evidenciase a ausência de esforços de coletas em um grupo particular de hospedeiros que compreenda um grupo monofilético -ou seja, proximamente relacionado -e/ou a preocupação em obter um número representativo de uma determinada espécie -seja ela de parasitas ou de hospedeiros.…”