Lacistorhynchidae family 28S alignment

Aim: Trypanorhyncha cestodes comprise a wide range of heteroxenous
parasites infecting elasmobranchs as definitive hosts, with crustaceans,
squids, and fishes acting as intermediate/paratenic hosts. Limited data
exist on the larval infection of these cestodes and the role of
intermediate and paratenic hosts in the life cycle of these parasites. In
this study, we investigated the factors that determine the occurrence and
the level of infection of Grillotia plerocerci in the skeletal muscles of
various deep sea benthonic sharks and analysed the parasites through an
integrative taxonomic approach. Location: Gulf of Naples, Mediterranean
Sea. Methods: Sharks obtained as bycatch of commercial trawling activities
(i.e., Etmopterus spinax, Galeus melastomus and Scyliorhinus canicula)
were used in this study. Data from a limited number of Dalatias licha and
Scyliorhinus stellaris were also included. Grillotia plerocerci were
molecularly characterized using the partial 28S large subunit rDNA.
Boosted regression trees were used to model the relationship between the
abundance of infection with both morphological and physiological
predictors in each host. Results: Plerocerci of Grillotia were detected in
all shark species except S. stellaris. Host species significantly differed
in terms of parasite abundance, with the highest and lowest prevalence and
abundance of infection detected in G. melastomus and E. spinax,
respectively. The relative influence of the traits involved in explaining
the parasite abundance were related to the host size in G. melastomus,
while both morphology- and physiology-related traits (e.g., gonadosomatic
and hepatosomatic indices) explained the patterns observed in E. spinax
and S. canicula. The 28S rDNA sequences shared identity of ∼99.40% with a
Grillotia species previously found in the Mediterranean Sea. At
intraspecific level, two different genotypes were found. A first type was
retrieved only from D. licha, whereas a second type was found in G.
melastomus, E. spinax, and S. canicula. Main conclusions: Present results
suggest that the two genotypes could be involved in different
consumer-resource systems and confirm most of the examined shark species
as transport hosts of Grillotia species for unknown larger top predators.