Molecular data confirm the species status of Neoechinorhynchus personatus and N. yamagutii (Acanthocephala, Neoechinorhynchidae) from the Atlantic and Pacific grey mullets (Teleostei, Mugilidae)

Abstract

Neoechinorhynchus is known to be the most
diverse acanthocephalan taxon with worldwide distribution; its species are characterized by uniformity
of anatomical organization. The taxonomic status of Neoechinorhynchus agilis s. l. from grey mullets was
recently reviewed that resulted in description of two new species, Neoechinorhynchus (Hebesoma) personatus
and Neoechinorhynchus (Hebesoma) yamagutii. In the current study,18S rRNA partial gene sequences
were obtained to molecularly characterize N. (N.) agilis, N. (H.) personatus and N. (H.) yamagutii
from grey mullets, Chelonlabrosus and Mugil cephalus, in the North-East Atlantic, the Japan, Azov and
Mediterranean Seas. The universal (F-566 and R-1200) and specific eukaryotic set primers were used to
amplify specimens from each species of Neoechinorhynchus. It has been found that three species can be
clearly recognized using universal primers, which allow to obtain sequences of 590 to 664 bp in length.
The genetic divergences estimated between three species sequenced here were relatively high, at ranged
between 2.08 and 6.57 %. Phylogenetic analysis demonstrates that the studied species of Neoechinorhynchus
from grey mullet fish share common ancestor, despite their different geographic location, and are
closely related. The terminal position of N. (N.) agilis and N. (H.) personatus on the evolution tree and
the low genetic divergence found between them suggests the recent emergence of this group and that the
colonization of the North-East Atlantic and the Mediterranean regions could represent a single event. Our
phylogenetic analysis, which included several species of the subgenera Neoechinorhynchus and Hebesoma,
showed that the latter is a polyphyletic taxon.