Morphology and molecular characterization of a new species of Tereancistrum parasite from the gills of Brycon nattereri.

Abstract

A new species of Tereancistrum Kritsky, Thatcher & Kayton, 1980, collected from the gills of Brycon nattereri (Bryconidae) in the Cerrado, in the state of Goiás, Brazil, is described based on morphological and molecular data, based on the mitochondrial cytochrome c oxidase subunit 1 (COI) gene region. Tereancistrum campanum n. sp. is distinguished from all its congeners by the unique 'bell-shaped' accessory piece in the male copulatory complex. Molecular analysis revealed that the specimens analyzed formed a distinct group from other Tereancistrum sequences and that the sequences of Tereancistrum kerri showed genetic divergence when compared to T. campanum n. sp., confirming the molecular distinction between the two species. This study also expands the knowledge of parasitic diversity in the Tocantins-Araguaia River Basin and extends the geographical distribution of the genus Tereancistrum. The combination of morphological and genetic data was essential for delimiting this new species, highlighting the importance of integrative approaches in understanding the diversity of monogeneans in freshwater fish in Brazil.