Phylogenetic position of the South American freshwater Rhipidocotyle santaensis (Digenea:Bucephalidae) based on partial 28S rDNA.

MARTIN MIGUEL MONTES; CLARA VERCELLINI; NICOLAS OSTOICH; MARINA IBAÑEZ SHIMABUKURO; GASTON CAVALLO; GERMAN REIG CARDARELLA; SERGIO R. MARTORELLI

PARASITOLOGY RESEARCH

SPRINGER

Lugar: Berlin; Año: 2023

0932-0113

The family Bucephalidae comprises nine subfamilies, the most important being Bucephalinae with eight genera. Among these, the genus Rhipidocotyle has been found in marine and freshwater environments from Asia, Europe, Oceania and America. Previous studies of Rhipidocotyle santanaensis have dealt with its morphology or host’s ecology. Here we provide a phylogenetic analysis based on two 28S rDNA sequences from R. santanaensis parasitizing the freshwater fish Acestrorhynchus pantaneiro from the Ibera Lagoon (Corrientes Province, Argentina). The 28S rDNA tree showed that it clustered together with Rhipidocotyle species from Middle and North America, suggesting a common history. Bucephalinae appears to have undergone four evolutionary processes: first, the diversification within the same host family; second, more than one successful infection by the same host family in different geographic regions; third, “jumping” between host families; and, finally, successful invasion of the freshwater environment (occurring in at least four different events in the subfamily). We hypothesize that R. santanaensis entered the freshwater environment by a jumping event from some unknown marine host family when a seawater ingression took place in South America during the Late Quaternary. This is the first report of a Bucephalinae species from South America to be sequenced. Further sequencing will contribute to shed light on the evolutionary relationships between South American members of this group from marine and, especially, freshwater environments.