Abstract
A new genus and species of
Clavella
-like specimens parasitic on
Macrourus holotrachys
, previously reported as a host for
Clavella adunca
, clearly differ from the latter in the position and condition of the antennal sympod and rami, which are uniramous in
C. adunca
but biramous in the new species. Additional morphological traits, such as antennule armature, maxillary size, and the absence of basal swelling on the cephalothorax, support these differences. Molecular analyses corroborate these distinctions. The 28S rDNA sequences of
Neoclavella holotrachia
gen. nov. et sp. nov
. show genetic divergence of 4.1–4.7% and 6.2–6.8% from those of
C. adunca
and Lernaeopodidae gen. sp., respectively, all of which cluster within a strongly supported clade.
Clavellomimus macruri
exhibits sequence divergence with
Clavellotis girellae
(15.3%) and with
Clavellotis dilatata
(15.5%), although the corresponding nodes in the phylogram are weakly supported. COI mtDNA sequences of
Neoclavella holotrachia
gen. nov. et sp. nov
. grouped together with
Clavella
spp. in a strongly supported node, with genetic distances ranging from 17.3% to 18.2% between the new genus and the other species. These results suggest that
Macrourus holotrachys
and possibly other
Macrourus
species are not hosts for
C. adunca
, as previously reported. Alternatively,
M. holotrachys
may be parasitized by both
C. adunca
and the new species. These findings suggest that some previous records of
C. adunca
from fishes off Chile may have been misidentified.