Biospeedotrema

Bray, R. A., Waeschenbach, A., Dyal, P., Littlewood, D. T. J. & Morand, S., 2014, New digeneans (Opecoelidae) from hydrothermal vent fishes in the south eastern Pacific Ocean, including one new genus and five new species, Zootaxa 3768 (1), pp. 73-87 : 74-75

Genus Biospeedotrema n. g.

urn:lsid:zoobank.org:act:6A819058-BDC2-4752-A4DB-9A47A5EC8BDD

Diagnosis. Body small, broadly pyriform to distinctly wider than long. Tegument unarmed, but may have annular wrinkles. Oral sucker subglobular to transversely oval, subterminal to terminal. Ventral sucker rounded to oval, larger than oral sucker, just pre-equatorial. Prepharynx short, dorsal to oral sucker. Pharynx large, subglobular to oval. Oesophagus distinct. Intestinal bifurcation about equatorial, dorsal to ventral sucker. Caeca blind, wide, divergent, reaching almost to or just past testes, not to posterior extremity. Testes two, oval, pyriform, may be lobate, symmetrical to slightly oblique, in anterior hindbody. Cirrus sac claviform, reaches dorsally to ventral sucker. Internal seminal vesicle saccular. Pars prostatica long, narrow, surrounded by gland-cells or indistinct. Ejaculatory duct short to long. Genital atrium distinct. Genital pore median to slightly dextrally submedian, immediately anterior to ventral sucker. Ovary subglobular, oval or subtriangular, just anterior to or overlapping right testis, overlapping ventral sucker. Seminal receptacle uterine. Laurer’s canal opens dorsally at about level of posterior margin in ventral sucker or anterior hindbody. Mehlis’ gland ventral to ovary. Uterus reaching between testes, or distinctly into post-testicular region. Eggs large, tanned, operculate, relatively few. Metraterm not distinct. Vitellarium follicular, in lateral fields from pharynx or oral sucker to just into post-testicular region, mainly lateral to caeca. Excretory pore terminal. Vesicle short, flattens into broad vesicle just posterior to testes. Type species Biospeedotrema jolliveti n. sp.

Etymology. This new genus is named after the Biospeedo expedition on which the material was collected.

Remarks. Biospeedotrema n. gen. is placed in the subfamily Stenakrinae as its members have a welldeveloped muscular cirrus sac and a uterine seminal receptacle. Cribb (2005) recognised six genera in the subfamily. The ovary is usually more or less globular to oval, but can be subtriangular. Utilising the key in Cribb (2005) the closest genus is Caudotestis Issaitschikov, 1928 (see below), but Biospeedotrema differs in the more or less symmetrical testicular configuration, with the uterus passing between the testes, sometimes distinctly into the post-testicular region. Of the four species of Stenakron Stafford, 1904 recognised by Cribb (2005), only one has symmetrical testes, namely Stenakron vitellosum ( Manter, 1934) from the shortbeard codling Laemonema barbatulum Goode & Bean ( Gadiformes , Moridae ) in 538 +m depth (294 + fathoms) off Tortugas, Florida ( Manter 1934). It has a trilobed ovary (a characteristic of the genus) and the uterus does not extend posteriorly to the testes. Biospeedotrema , Caudotestis and Stenakron are mainly parasites of deep-sea fishes ( Klimpel et al. 2009).