Description of a New Digenean (Zoogonidae) Genus and Species from Sub-Antarctic Fish Patagonotothen tessellata

Abstract

Whitegonimus ozoufae n. gen., n. sp. (Digenea: Zoogonidae) is reported from the stomach of Patagonotothen tessellata in the harbor of Ushuaia in the Beagle Channel (Tierra del Fuego, Argentina) at a depth of 7–9 m. The female genital system structure indicates the new taxon belongs in the subfamily Lepidophyllinae (Zoogonidae). None of the genera previously described is similar to the new genus. The most important taxonomic features are the spined tegument, lack of enlarged circumoral spines, gonads arranged in tandem, long caeca, vitelline follicles extending from the level of the ventral sucker to the posterior end of anterior testis, and a Y-shaped excretory vesicle. Only 3 genera, Overstreetia, Anarhichotrema, and Pseudopalaeorchis, have testes arranged in tandem, but they differ from the new genus in possessing enlarged circumoral spines, oral sucker size, esophagus length, length of caeca, vitellaria restricted to hindbody, the form of the ovary, and an I-shaped excretory vesicle.