Cardicola beveridgei n. sp. (Digenea: Aporocotylidae) from the mangrove jack, Lutjanus argentimaculatus (Perciformes: Lutjanidae), and C. bullardi n. sp. from the Australian spotted mackerel, Scomberomorus munroi (Perciformes: Scombridae), from the northern Great Barrier Reef
Graphical abstract
Introduction
The parasite fauna of teleost fishes of the Great Barrier Reef (GBR) and throughout the Indo-West Pacific Region (IWP) remains incompletely known, both at genus and species levels [1]. Within the Digenea (Platyhelminthes), the family Aporocotylidae Odhner, 1912 (syn. Sanguinicolidae von Graff, 1907; the blood flukes of fishes) is as poorly known as any group of trematodes [2] and the taxonomic confusion within the family is not exceeded in any other [3]. This is perhaps because these parasitic flatworms are especially cryptic; not only are they hidden within the circulatory system of teleosts, elasmobranchs and holocephalans, they are also not limited to the heart or gills, which are relatively obvious and easily examined (e.g., Skoulekia meningialis Alama-Bermejo, Montero, Raga & Holzer, 2011 is found in the vessels surrounding the optic lobes of the brain; see [4]). In addition, many aporocotylid species are characterised by low prevalence and/or intensities of infection (e.g. [5], [6]), which represent a major obstacle to current efforts aimed at clarifying taxonomic and systematic aspects of this family.
Cardicola Short, 1953 currently has the greatest number of marine species of any genus in the Aporocotylidae (although future taxonomic revision may alter this; see [7]). In 2006, eight species of Cardicola were reported from six species of the Siganidae (rabbitfishes) and one species of the Lutjanidae (snappers) from Australia from the southern and northern GBR, Ningaloo Reef and Moreton Bay [5]. Due to difficulties in obtaining sufficient study material during that investigation four further putative species were reported, but not described, from either a single morphological specimen or a single sequence from the second internal transcribed spacer (ITS2) of ribosomal DNA (rDNA). Here, as part of an ongoing survey of the Aporocotylidae of fishes of the waters surrounding Lizard Island, we are now able to describe two of these as new. Employing a combined morphological and molecular-based approach, we here describe Cardicola beveridgei n. sp. from the mangrove jack, Lutjanus argentimaculatus (Forsskål) (Lutjanidae), and C. bullardi n. sp. from the Australian spotted mackerel, Scomberomorus munroi Collette & Russo (Scombridae).
Section snippets
Sample collection
Fishes were collected from off Lizard Island (14°40′S 145°27′E), on the northern GBR, by spear and line fishing, and were euthanised via neural pithing. Immediately upon death the heart, gills and viscera were excised and examined separately in 0.85% saline solution, utilising a stereomicroscope. The three chambers of the heart were dissected along their lengths using micro-scissors and gently teased apart with fine forceps before being flushed with saline solution. Each branchial arch was
Comparative DNA analysis
We conducted sequence analysis of the amplicons (n = 2) representing both species described here. These sequences had mean nucleotide frequencies of 21.3 (A), 16.7 (C), 26.3 (G) and 35.7 (T) (sequence represented by GenBank accession no. DQ059632; [5]) and 20.2 (A), 16.9 (C), 26.7 (G) and 36.2 (T) (KF752497), and were 60 bases different from each other (14% over 420 nucleotide positions in the aligned dataset). Comparison of the present data with information currently available in GenBank
Taxonomy
According to Bullard [17] there are currently 25 valid species of Cardicola. This figure excludes Cardicola congruenta Lebedev & Mamaev, 1968, Cardicola grandis Lebedev & Mamaev, 1968 (see [18]), Cardicola ahi Yamaguti, 1970, and Cardicola kurochkini (Parukhin, 1976) Bullard & Overstreet, 2006 (see [7]), which are currently considered incertae sedis. C. beveridgei n. sp. may be differentiated from all current species, except C. milleri Nolan & Cribb, 2006 and C. aurata, by the combined
Conflict of interest
The authors have no conflict of interest.
Acknowledgements
This study was partly funded by the Australian Research Council and the Australian Biological Resources Study grants awarded to THC. TLM is supported by a Queensland Smart Futures Fund Fellowship. CC is supported by an NHMRC Peter Doherty Early Career Fellowship. We gratefully thank the staff of the Lizard Island Research Station for their support and hospitality during our stays.
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2019, International Journal for Parasitology: Parasites and WildlifeHigh-intensity cardiac infections of Phthinomita heinigerae n. sp. (Digenea: Aporocotylidae) in the orangelined cardinalfish, Taeniamia fucata (Cantor), off Heron Island on the Great Barrier Reef
2016, Parasitology InternationalCitation Excerpt :The hearts of some infected apogonids were preserved in 10% formalin (room temperature), for histological examination. Fixed worms were washed, stained, and mounted as described by Nolan et al. [8]. Drawings were completed using a drawing tube attached to an Olympus BX53 compound microscope with Nomarski differential interference contrast (DIC) optics.
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