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

MONTES, MARTIN MIGUEL; VERCELLINI, CLARA; OSTOICH, NICOLAS; SHIMABUKURO, MARINA IBAÑEZ; CAVALLO, GASTÓN; REIG CARDARELLA, GERMAN; MARTORELLI, SERGIO

PARASITOLOGY RESEARCH

SPRINGER

Lugar: Berlin; Año: 2023 p. 1 - 10

0932-0113

The family Bucephalidae is comprised of nine subfamilies, the most important being Bucephalinae with eight genera. Amongthese, the genus Rhipidocotyle has been found in marine and freshwater environments all over the world. Previous studies ofRhipidocotyle santanaensis have dealt with its morphology or host’s ecology. Here, we provide a phylogenetic analysis based ontwo 28S rDNA sequences from R. santanaensis parasitizing the freshwater fsh Acestrorhynchus pantaneiro from the Ibera Lagoon(Corrientes Province, Argentina). The 28S rDNA tree showed that it clustered together with Rhipidocotyle species from Middleand North America, suggesting a common history. Bucephalinae appears to have undergone four evolutionary processes: frst, thediversifcation within the same host family; second, more than one successful infection of the same host family in diferent geographic regions; third, “jumping” between host families; and, fnally, successful invasion of the freshwater environment (occurringin at least four diferent 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 LateQuaternary. This is the frst sequenced Bucephalinae species from South America. Further sequencing will help shed light on theevolutionary relationships between South American members of this group from marine and, especially, freshwater environments.