The first record of Ligophorus Euzet & Suriano, 1977 (Monogenea: Dactylogyridae) on Crenimugil buchanani (Teleostei: Muglidae) from Thailand based on morphological and molecular analyses

Abstract

Ligophorus satunensis n. sp. was collected from the bluetail mullet, Crenimugil buchanani (Bleeker, 1853), caught off Satun, Thailand, representing the first report of the Ligophorus species in Thailand. The new species is most similar to Ligophorus fenestrum Soo & Lim, 2012 in its fenestrated dorsal hamuli, a ventral bar with a long, bifurcated anteromedian protuberance (AMP) without lateral pieces, and a non-sclerotized vagina. However, it differs from the latter in its dorsal hamuli (up to two layers of fenestrations of the dorsal hamuli in L. satunensis n. sp. vs six layers in L. fenestrum), ventral hamuli (nonfenestrated vs fenestrated), penis (turning a full circle before reaching the genital pore vs turning less than half a circle), and its accessory piece (non-grooved basally and grooved distally vs simply grooved along its entire length). A single specimen, very similar to L. satunensis n. sp., obtained from the same host fish, which can be differentiated from the latter by a considerably shorter AMP of the ventral bar and a smaller and slender dorsal hamuli, is tentatively designated here as Ligophorus sp. Moreover, the phylogenetic trees constructed from the concatenated sequences of partial large-subunit nuclear ribosomal DNA (28S) and nuclear ribosomal internal transcribed spacer 1 (ITS1) regions support that L. satunensis n. sp. is a new species closely related to L. fenestrum.

First morphological and phylogenetic data on Ligophorus kaohsianghsieni (Platyhelminthes: Monogenea) from the Black Sea and the Sea of Japan and molecular evidence of deep divergence of sympatric Ligophorus species parasitizing Planiliza haematocheilus

“…Monogeneans of Ligophorus Euzet et Suriano, 1977 are specific gill parasites of fish from the family Mugilidae Jarocki, 1822. The genus currently includes 66 nominal species (Euzet & Suriano, 1977; Dmitrieva et al , 2007, 2012, 2013a; Abdallah et al , 2009; Soo & Lim, 2012, 2013; El Hafidi et al , 2013a, b; Kritsky et al , 2013; Sarabeev et al , 2013; Marchiori et al , 2015; Rodríguez-González et al , 2015a, 2015b; Khang et al , 2016; Pakdee et al , 2018). Identification of Ligophorus species is based mainly on the morphology of hard structures of the haptor and the distal parts of the female and male reproductive systems (Euzet & Suriano, 1977; Sarabeev et al , 2013).…”

“…Many species are very morphologically similar to each other, creating difficulties for delimitation of species (Euzet & Suriano, 1977; Dmitrieva et al , 2007, 2013a). Some of them were distinguished on the basis of DNA sequence data (Marchiori et al , 2015; Pakdee et al , 2018). However, these data are discrete or insufficient, representing 127 sequences of the different parts of the nuclear DNA ribosomal cluster for only 32 species (), including 12 species from the Mediterranean Sea and two species from the Azov Sea (Mollaret et al , 2000; Plaisance et al , 2005; Blasco-Costa et al , 2012; Rodríguez-González et al , 2015a), two species from the West Atlantic Ocean off Brasilia (Marchiori et al , 2015), 14 species from the East Indian Ocean off Malaysia (Soo et al , 2015; Khang et al , 2016) and for three species from the South China Sea (Wu et al , 2006, 2007; Pakdee et al , 2018).…”

“…Some of them were distinguished on the basis of DNA sequence data (Marchiori et al , 2015; Pakdee et al , 2018). However, these data are discrete or insufficient, representing 127 sequences of the different parts of the nuclear DNA ribosomal cluster for only 32 species (), including 12 species from the Mediterranean Sea and two species from the Azov Sea (Mollaret et al , 2000; Plaisance et al , 2005; Blasco-Costa et al , 2012; Rodríguez-González et al , 2015a), two species from the West Atlantic Ocean off Brasilia (Marchiori et al , 2015), 14 species from the East Indian Ocean off Malaysia (Soo et al , 2015; Khang et al , 2016) and for three species from the South China Sea (Wu et al , 2006, 2007; Pakdee et al , 2018). Data on DNA sequences for Ligophorus species from the Black Sea and the Sea of Japan are still lacking.…”

Molecular-genetic approaches to species identification of platyhelminthes of the genus <i>Ligophorus</i> (Monogenea) parasitising flathead mullet

“…The 18S, ITS1, 5.8S and 28S fragments were obtained for 12 species from the Mediterranean Sea and 2 species from the Black Sea (Blasco-Costa et al, 2012;Rodríguez-González et al, 2015). For two species off the coast of Brazil, 18S, ITS1, 5.8S and 28S were sequenced (Marchiori et al, 2015), and 18S, 28S and ITS1 fragments were obtained for 14 species from the Indian Ocean (Soo et al, 2015;Khang et al, 2016;Pakdee et al, 2019). Several studies (Blasco-Costa et al, 2012;Rodríguez-González et al, 2015;Khang et al, 2016) have compared morphological and genetic variability, showing a greater degree of congruence between phylogenetic reconstructions based on these data, suggesting that the use of ribosomal cluster sequences for genotyping species of this genus is promising.…”