Grillotia (Cestoda: Trypanorhyncha) plerocerci in an anglerfish (Lophius piscatorius) from the Tyrrhenian Sea

Abstract

Trypanorhynch cestodes are common parasites of marine fish with complicated life cycles which have been suggested as model taxa to study the evolution of marine helminth parasites and their life cycles. Among the Trypanorhyncha, the genus Grillotia includes 18 valid species, of which only four have been found in Mediterranean fish hosts. Morphological, histopathological, and molecular data are presented on a massive Grillotia plerocercus infection in an anglerfish (Lophius piscatorius) from the Tyrrhenian Sea. BLAST analysis of the 28S rDNA sequences revealed 99% similarity between specimens here found and a G. (Bathygrillotia) rowei sequence available in GenBank with a total of six nucleotide site differences. A morphological study suggested that the Grillotia sp. here reported did not match important characters to those previously reported from the Mediterranean Sea. Taking in account these differences, we prefer to place these specimens within Grillotia sensu lato until more material is available for study including sequences from adult specimens of Grillotia spp. from the Mediterranean Sea.

First molecular detection of the parasites Molicola uncinatus and Hepatoxylon trichiuri (Cestoda: Trypanorhyncha) infecting the silver scabbardfish Lepidopus caudatus from the Central Mediterranean Sea: Implications for the seafood quality and safety

“…Abdelsalam et al (2016) identified, by molecular markers, plerocerci of Callitetrarhynchus gracilis (Rudolphi, 1819) in the little tunny (Euthynnus alletteratus Rafinesque, 1810), caught in the South-Eastern Mediterranean Sea. A massive infection with plerocerci of Grillotia (Guiart, 1927) was molecularly identified in an anglerfish by Santoro et al (2018). In addition, the presence of Gymnorhynchus isuri Robinson, 1959 in Mola mola (Linnaeus, 1758) from the Mediterranean Sea was also genetically detected (Santoro et al, 2020).…”

“…Indeed, the retraction of the tentacular apparatus inside the tentacular sheaths of the merocercoids makes difficult to refer the recovered specimens to the genus level; this happened also in the case of the specimens collected in the present work. Conversely, molecular systematics applied to these taxa allows the correct identification of several species, even at the larval forms, capable of infecting a wide range of intermediate and/or transport hosts (Abdelsalam et al, 2016;Olson et al, 2010;Santoro et al, 2018, Santoro, Palomba, Mattiucci, Osca, & Crocetta, 2020. Abdelsalam et al (2016) identified, by molecular markers, plerocerci of Callitetrarhynchus gracilis (Rudolphi, 1819) in the little tunny (Euthynnus alletteratus Rafinesque, 1810), caught in the South-Eastern Mediterranean Sea.…”

“…Their occurrence in the muscles alters the fish flesh quality, reducing the marketability of commercially important fish species (Dias, Sao Clemente, Pinto, & Knoff, 2011;da Fonseca, de Sao Clemente, Felizardo, Gomes, & Knoff, 2012;Deardorff, Raybourne, & Mattis, 1984;Giarratana et al, 2014;Samn, Metwally, Zeina, & Khalaf Allah, 2014;Abdelsalam et al, 2016;Santoro et al, 2018;Oliveira, Kuraiem, Fonseca, Gomes, & Knoff, 2019;Guardone et al, 2020). Heavily infected fish fillets result unappealing to consumers; thus, the presence of these parasites causes economic loss to the fishing industry (Abdelsalam et al, 2016;Deardorff et al, 1984;Giarratana et al, 2014;Samn et al, 2014;Santoro et al, 2018). Few cases of accidental human ingestion of Trypanorhyncha larvae were reported, showing no clear evidence of pathogenic effects in humans (Bates, 1990;Lima dos Santos & Howgate, 2011).…”

“…However, the identification of the larval stages of trypanorhynch tapeworms may be difficult when based on morphological characters, especially due to the retraction of the tentacular apparatus inside the tentacular sheaths (Palm, 1997;Santoro et al, 2018). In this concern, the genetic/molecular methodologies are a valuable tool for the characterization and identification of the species of Trypanorhyncha, largely contributing to disentangle their systematics (Olson et al, 2010;Palm et al, 2009), as well as to establish phylogenetic relationships among taxa.…”

A molecular and ecological study of Grillotia (Cestoda: Trypanorhyncha) larval infection in small to mid‐sized benthonic sharks in the Gulf of Naples, Mediterranean Sea

“…Moreover, no molecular data exist from the Mediterranean Sea except for a recent report of a massive infection of plerocerci by an unidentified Grillotia species in the anglerfish Lophius piscatorius Linnaeus, 1758 (Santoro et al, 2018).…”