Phylogenetic position of the Neotropical Family Zonocotylidae (Paramphistomoidea) using partial 28S rDNA sequences

MONTES, M.M.; ARRASCAETA, F.K.; BARNECHE, J.A.; BALCAZAR, D.; REIG CARDARELLA, G.F.; MARTORELLI, S.R.

J. HELMINTHOL.

Cambridge University Press

Año: 2023 vol. 97

0022-149X

Six families belonging to the Paramphistomoidea superfamily have been reported in SouthAmerica, with only Zonocotylidae and Balanorchiidae being endemic. The Zonocotylidae wasinitially classified as Aspidogastrea and then as a paramphistomoid. This family comprises a singlegenus, Zononocotyle, with two species. It is primarily characterized by having an attachment organwith transverse ridges and a single testis. The placement of Zonocotylidae within Paramphisto-moidea is controversial, as some researchers speculate that this genus is the most primitivemember of the superfamily, while others consider it an aberrant form. The main objectives ofour study were to provide the first sequences of Zonocotylidae and elucidate its phylogeneticposition. We amplified the 28S gene from two parasites from Cyphocharax sp. from Punta Lara,Buenos Aires. Newly generated sequences were used to infer the phylogenetic relationships withother Paramphistomoidea species using a Bayesian approach. Zonocotylidae were clustered withDadayiinae and Kalitrematinae (Cladorchiidae) species found in freshwater fishes from SouthAmerica. Genetic analyses revealed that they formed a well-supported clade with cladorchiids infreshwater hosts from South America. However, the occurrence of genera of Cladorchiidae inNorth America, Middle America, Asia, and Australia suggested its polyphyletic nature and mayindicate the need for the erection of new families. Other Paramphistomoidea families may alsorequire further revision. The addition of new sequences to phylogenetic analyses along with acomprehensive and more detailed description of the genera will help resolve the relationshipswithin this group.