First description of male Philometra thaiensis Moravec, Fiala et Dyková, 2004 (Nematoda: Philometridae) from the body cavity of the eyespot pufferfish Tetraodon biocellatus Tirant, and evolutionary relationships of this species with other dracunculoids as inferred from SSU rRNA gene sequences

Abstract

236 SummaryFinding male philometrid nematodes is essential for taxonomic identification among congeneric species. In this study, male Philometra thaiensis Moravec, Fiala et Dyková, 2004 were collected and described for the first time, from the body cavity of the freshwater fish (eyespot pufferfish) Tetraodon biocellatus Tirant (Tetraodontiformes, Tetraodontidae), and conspecific females were redescribed based on the additional morphological biometrics examined. Molecular examination was carried out on the small subunit 18S rRNA, revealing the evolutionary relationships of P. thaiensis and reported philometrid species (Philometra and Philometroides) from Japan with other dracunculoids deposited in the GenBank. Based on the molecular data, there are some genera (Philometra, Philometroides, Clavinema, and Margolisianum [genus inquirendum]) requiring further morphological re-evaluation that should be supported with molecular data.

Morphological and Molecular Characterization of Philometroides seriolae from Japanese Amberjack Seriola quinqueradiata caught in East Sea, Republic of Korea

“…The present specimens were equipped with typical papillae distributed on their body surface, which are key characteristics of the genus Philometroides [10]. The morphological features (the arrangement of organs and their measurements) seemed well fitted with the morphological characteristics of P. seriolae as described by previous authors [2][3][4]10]. Moravec and Ogawa [2] mentioned that subgravid females show 14 papillae with a pair of amphids arranged in 2 circles.…”

“…Due to the distinct morphological differences with the genus Philometra Costa, 1845, philometrid nematodes equipped with cuticular bosses have been classified as genus Philometroides. However, the current results based on phylogenetic analysis revealed that cuticular bosses might not be a major key to identify the genus [4]. However, here the genus was retained until the taxonomic status could be revised.…”

“…Polymerase chain reaction (PCR) was conducted to amplify the target gene, small subunit ribosomal RNA (SSU rRNA), using a GeneAmp PCR system 9700 (Applied Biosystems, Langen, Germany). The PCR conditions and primer sets followed the protocols of a previous study on philometrids [4]. The PCR products were purified using a gel extraction kit (Qiagen Ltd., Valencia, California, USA).…”

“…The PCR products were purified using a gel extraction kit (Qiagen Ltd., Valencia, California, USA). The products were then sequenced using the Applied Biosystems 3730xl DNA Analyzer (Thermo Fisher Scientific, Waltham, Massachusetts, USA) equipped in Cosmogenetech, Daejeon, Korea, with the same primer sets as those used for PCR [4]. For molecular comparisons, the obtained sequences were assembled and edited using ClustalW [5], Mega7 [6], and BLASTn analysis (http://blast.ncbi.nlm.nih.gov/Blast.cgi).…”

Redescription and genetic characterization of Philometra lagocephali Moravec et Justine 2008 (Nematoda: Philometridae) from Lagocephalus lunaris (Bloch and Schneider) (Tetraodontiformes: Tetradontidae) in the South China Sea

“…DNA was eluted in elution buffer and kept at -20°C untiluse. The partial 18S rDNA was amplified by PCR using the primers 35f (forward: 5′-TATAATGGTGAAACCGCGAACGGC-3′) and 18gM (reverse: 5′-GGAAACCTTGTTACGACTTTTGCC-3′) (Quiazon et al 2009). The cox1 region was amplified by PCR using the primers COXIF (forward: 5′-TTTTTTGGTCAT CCTGAG GTTTAT-3′) and COXIR (5′-ACATAATGAAAAT-GACTAACAAC -3′).…”