Two known and one new species of Proctoeces from Australian teleosts: Variable host-specificity for closely related species identified through multi-locus molecular data

Abstract

Species of Proctoeces Odhner, 1911 (Trematoda: Fellodistomidae) have been reported from a wide range of marine animals globally. Members of the genus tend to lack strongly distinguishing morphological features for diagnosis, making identification difficult and the true number of species in the genus contentious. Combined morphological and molecular analyses were used to characterise three species of Proctoeces from Moreton Bay and the southern Great Barrier Reef. Data for two ribosomal regions and one mitochondrial region were generated for specimens collected from Australia. Three unique 18S-genotypes were identified which corresponded to subtle, but reliable, morphological differences. Two species of Proctoeces were identified from fishes of Moreton Bay, Proctoeces insolitus (Nicoll, 1915) Yamaguti, 1953 and P. major Yamaguti, 1934, and a third, P. choerodoni n. sp. from off Heron Island on the southern Great Barrier Reef. Phylogenetic analyses of partial 18S and partial 28S rDNA indicated that these three species differ from the four species reported outside of Australia for which sequence data are available. Phylogenetically, Proctoeces proved to be a reliable concept, with all species of Proctoeces that have been characterised genetically forming a well-supported clade in all analyses. Dramatically different patterns of host-specificity were identified for each of the three Australian species; P. insolitus apparently infects a single species of fish, P. choerodoni n. sp. infects multiple species of a single genus of fish, and P. major infects multiple species of two teleost orders.

The Pseudoplagioporinae, a new subfamily in the Opecoelidae Ozaki, 1925 (Trematoda) for a small clade parasitizing mainly lethrinid fishes, with three new species

“…In some cases, sequences of partial cox1 mtDNA were also generated. Genomic DNA extraction, PCR amplification, and sequencing protocols are as per Martin, Cutmore, and Cribb () and Wee, Cribb, Bray, and Cutmore (). Genomic DNA was extracted following a phenol/chloroform procedure based on Sambrook and Russell ().…”

“…The target regions were amplified via PCR using an MJ Research PTC‐150 thermocycler using the primers detailed in Table and the cycling schedules detailed in Martin, Cutmore, and Cribb () for the ribosomal markers and in Wee et al. () for cox1 mtDNA. These protocols yield the entire ITS2 region, plus part of the 5.8S rRNA gene and part of the 28S rRNA gene, almost the entire 18S rRNA gene, partial 28S rRNA gene data, including the phylogenetically informative D1–D3 domains, and partial cox1 mtDNA.…”

“…Reverse, amplification only 5′-CTT GTT ACG ACT TTT ACT TCC-3′ Littlewood and Olson (2001) Dig_cox1Fa cox1 Forward 5′-ATG ATWTTY TTY TTY YTD ATG CC-3′ Wee et al (2017) Dig_cox1R cox1 Reverse 5′-TCN GGR TGH CCR AAR AAY CAA AA-3′ Wee et al (2017) xiphidiates, Stephanostomum pristis (Deslongchamps, 1824) Looss, 1899 (Acanthocolpidae Lühe, 1906) and Zalophotrema hepaticum Stunkard & Alvey, 1929(Brachycladiidae Odhner, 1905 were added as the outgroup, based on previous analyses (Bray, Webster, Bartoli, & Littlewood, 2005;Littlewood et al, 2015). These alignments were trimmed, and indels greater than a single base position and affecting >5% of sequences were removed, amounting to about 2% and 4% of the 18S and 28S base positions, respectively.…”

Lepotrema Ozaki, 1932 (Lepocreadiidae: Digenea) from Indo-Pacific fishes, with the description of eight new species, characterised by morphometric and molecular features

“…Specimens for molecular analysis were processed according to the protocols used by Sun et al ( 2014 ) and Wee et al ( 2017 ). The complete ITS2 rDNA region was amplified and sequenced using the primers 3S (Morgan & Blair, 1995 ) and ITS2.2 (Cribb et al, 1998 ), the partial D1-D3 28S rDNA region using LSU5 (Littlewood, 1994 ), 300F (Littlewood et al, 2000 ), ECD2 (Littlewood et al, 1997 ) and 1500R (Snyder & Tkach, 2001 ) and the partial cox 1 mtDNA region using Dig_cox1Fa (Wee et al, 2017 ) and Dig_cox1R (Wee et al, 2017 ). Geneious® version 10.2.3 (Kearse et al, 2012 ) was used to assemble and edit contiguous sequences and the start and end of the ITS2 rDNA region were determined by annotation through the ITS2 Database (Keller et al, 2009 ; Ankenbrand et al, 2015 ) using the ‘Metazoa’ model.…”

An Anomalous Phylogenetic Position for Deraiotrema platacis Machida, 1982 (Lepocreadiidae) from Platax pinnatus on the Great Barrier Reef

“…The protocols for molecular analysis were as described by Cutmore et al [5] and Wee et al [6]. The complete ITS2 rDNA region was amplified and sequenced using the primers 3S [7] and ITS2.2 [8], the partial D1-D3 28S rDNA region using LSU5 [9], 300F [10], ECD2 [11] and 1500R [12] and the partial cox1 mtDNA region using Dig_cox1Fa [6] and Dig_cox1R [6]. Assembly and editing of contiguous sequences utilised the Geneious ® version 10.2.3 [13] and the start and end of the ITS2 rDNA region were determined by annotation through the ITS2 Database [14,15] using the 'Metazoa' model.…”