Morphological identification and DNA barcoding of a new species of Parabrachiella (Siphonostomatoida: Lernaeopodidae) with aspects of their intraspecific variation

MONTES MARTIN MIGUEL; CASTRO ROMERO RAUL; MARTORELLI SERGIO

ACTA TROPICA

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2017

0001-706X

We present a detailed morphological description and DNA barcoding of Parabrachiella platensis n. sp. collected from Mugil liza Valenciennes in Samborombon Bay (Buenos Aires, Argentina). This new species was compared with two Parabrachiella species parasitic on mugilids: Parabrachiella exilis (Shiino, 1956) and Parabrachiella mugilis (Kabata, Raibaut et Ben Hassine, 1971) and differs from them in some characters like the shape of posterior processes, anal slit with two pairs of bipartite papillae, size of cephalothorax, trunk, maxilla, microhabitat on the host, and lack of caudal rami in Parabrachiella platensis n. sp. but present in P. exilis and P. mugilis. The new species was located in the nostrils and between the fin and the body of the host. Some minor morphological differences were observed in relation to the locations on the host. The molecular analysis conducted based on mtDNA-COI between specimens of the new species from fins and nostrils showed a genetic similarity of 99.8% supporting the fact that the specimens found represent a single species. The new species was also molecularly compared to other four species of Parabrachiella including P. exilis (parasitizing mugilid from Chile), Parabrachiella anisotremis, Parabrachiella auriculata, Parabrachiella merluccii, and P. hugu (the last two sequences were taken from the GenBank). The genetic distance of 9% among P. platensis n. sp. and the close morphological related species, P. exilis, allow to states that this two copepods on mugilids belong to different species validating the morphological differences found between them.