Molecular evidence supports the validity of three Parabrachiella species infecting mugilids

MONTES, MARTIN MIGUEL; CASTRO-ROMERO, RAUL; ÖKTENER, AHMET; BALCAZAR, DARIO; CARDARELLA, GERMAN FLAVIO REIG; MARTORELLI, SERGIO

ACTA TROPICA

ELSEVIER SCIENCE BV

Año: 2022 vol. 225

0001-706X

The parasitic copepod genus Parabrachiella is composed of 70 species, 14 of which are found in South America.The finding of new specimens of Parabrachiella mugilis from Turkey allowed us to compare the nucleotide sequencesof the mitochondrial cytochrome c oxidase subunit I (COI) gene of this species with those of the SouthAmerican Parabrachiella exilis and Parabrachiella platensis; all these species are parasites of mugilids. In addition,specimens of Parabrachiella fasciata, Parabrachiella oralis and Parabrachiella dispar from Chile, and Parabrachiellachevreuxi from Argentina were included in the comparison. Our results confirmed that the three Parabrachiellaspecies parasitizing mugilids, which had been identified by morphology, are valid entities. However, P. exilis wasrecently synonymized with P. mugilis. The latter species showed a great genetic distance from P. exilis (16%) andwas closer to Parabrachiella fasciata (13%) and to species with long posterior processes. Parabrachiella exilis andP. platensis (parasite on Mugil cephalus and Mugil liza, respectively) had a low genetic distance (9%) and Parabrachiellakabatai (parasite of Isacia conceptionis) had a low genetic distance (12-13%) from P. fasciata, P. platensisand P. exilis. In addition, the three parasitic copepods from South America have short and round posteriorprocesses compared to other species, which have long posterior processes. Most species with long posteriorprocesses are clustered together in a Pacific Ocean clade (P. hugu from the North Pacific Ocean), with theexception of P. chevreuxi, which has been found in the South Atlantic Ocean. This study adds seven new sequences,making a total of nine sequenced South American species of Parabrachiella.