Stanley D. King

Ieredactylus rivuli gen. et sp. nov. (Monogenea, Gyrodactylidae) from Rivulus hartii (Cyprinodontiformes, Rivulidae) in Trinidad

A new genus and species of Gyrodactylidae, Ieredactylus rivuli gen. et sp. nov. (Platyhelminthes, Monogenea), is described from the skin of Hart’s Rivulus (Rivulus hartii Boulenger), a cyprinodontiform fish collected from streams of the Caroni and Oropouche drainages and the Pitch Lake in Trinidad (prevalence all localities: 16.7–94.6%; mean parasite intensity 1–9 parasites/fish; range 1–34) with the holotype originating from a tributary of the Aripo River. This viviparous monogenean is distinctive from other genera of Gyrodactylidae by its split ventral bar membrane, the shape of its male copulatory organ, the presence of two conical accessory pieces associated with the hamulus root and two differently shaped marginal hook sickles. Its unique rDNA sequence shows the closest ITS2 similarity (70%) to Gyrodactyloides andriaschewii Bychowsky et Poljansky, 1953. The presence of I. rivuli gen. et sp. nov. in the Pitch Lake indicates an adaptation to extreme environmental conditions such as high temperatures and hydrocarbons and adverse pH. Guppies may potentially serve as temporary hosts. The parasite displays distinct behaviours, including a characteristic ‘swimming-like’ movement. The ecology and phylogeny of I. rivuli gen. et sp. nov. is discussed in relation to the diversity of other gyrodactylids in Trinidad.

The mitochondrial genome of Paragyrodactylus variegatus (Platyhelminthes: Monogenea): differences in major non-coding region and gene order compared to Gyrodactylus

BackgroundParagyrodactylus Gvosdev and Martechov, 1953, a viviparous genus of ectoparasite within the Gyrodactylidae, contains three nominal species all of which infect Asian river loaches. The group is suspected to be a basal lineage within Gyrodactylus Nordmann, 1832 sensu lato although this remains unclear. Further molecular study, beyond characterization of the standard Internal Transcribed Spacer region, is needed to clarify the evolutionary relationships within the family and the placement of this genus.MethodsThe mitochondrial genome of Paragyrodactylus variegatus You, King, Ye and Cone, 2014 was amplified in six parts from a single worm, sequenced using primer walking, annotated and analyzed using bioinformatic tools.ResultsThe mitochondrial genome of P. variegatus is 14,517xa0bp, containing 12 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, two ribosomal RNA (rRNA) genes and a major non-coding region (NCR). The overall Au2009+u2009T content of the mitochondrial genome is 76.3%, which is higher than all reported mitochondrial genomes of monogeneans. All of the 22 tRNAs have the typical cloverleaf secondary structure, except tRNACys, tRNASer1 and tRNASer2 that lack the dihydrouridine (DHU) arm. There are six domains (domain III is absent) and three domains in the inferred secondary structures of the large ribosomal subunit (rrnL) and small ribosomal subunit (rrnS), respectively. The NCR includes six 40xa0bp tandem repeat units and has the double identical poly-T stretches, stem-loop structure and some surrounding structure elements. The gene order (tRNAGln, tRNAMet and NCR) differs in arrangement compared to the mitochondrial genomes reported from Gyrodactylus spp.ConclusionThe Duplication and Random Loss Model and Recombination Model together are the most plausible explanations for the variation in gene order. Both morphological characters and characteristics of the mitochondrial genome support Paragyrodactylus as a distinct genus from Gyrodactylus. Considering their specific distribution and known hosts, we believe that Paragyrodactylus is a relict freshwater lineage of viviparous monogenean isolated in the high plateaus of central Asia on closely related river loaches.

Mitochondrial genomes of two phlebotomine sand flies, Phlebotomus chinensis and Phlebotomus papatasi (Diptera: Nematocera), the first representatives from the family Psychodidae.

BackgroundLeishmaniasis is a worldwide but neglected disease of humans and animal transmitted by sand flies, vectors that also transmit other important diseases. Mitochondrial genomes contain abundant information for population genetic and phylogenetic studies, important in disease management. However, the available mitochondrial sequences of these crucial vectors are limited, emphasizing the need for developing more mitochondrial genetic markers.MethodsThe complete mitochondrial genome of Phlebotomus chinensis was amplified in eight fragments and sequenced using primer walking. The mitochondrial genome of Phlebotomus papatasi was reconstructed from whole-genome sequencing data available on Genbank. The phylogenetic relationship of 24 selected representatives of Diptera was deduced from codon positions 1 and 2 for 13 protein coding genes, using Bayesian inference (BI) and maximum likelihood (ML) methods.ResultsWe provide the first Phlebotomus (P. chinensis and P. papatasi) mitochondrial genomes. Both genomes contain 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes, and an Au2009+u2009T-rich region. The gene order of Phlebotomus mitochondrial genomes is identical with the ancestral gene order of insect. Phylogenetic analyses demonstrated that Psychodidae and Tanyderidae are sister taxa. Potential markers for population genetic study of Phlebotomus species were also revealed.ConclusionThe generated mitochondrial genomes of P. chinensis and P. papatasi represent a useful resource for comparative genomic studies and provide valuable future markers for the population genetic study of these important Leishmania vectors. Our results also preliminary demonstrate the phylogenetic placement of Psychodidae based on their mitochondrial genomes.

Comparative analyses within Gyrodactylus (Platyhelminthes: Monogenea) mitochondrial genomes and conserved polymerase chain reaction primers for gyrodactylid mitochondrial DNA.

In this study, we describe the complete mitochondrial genomes of Gyrodactylus brachymystacis and Gyrodactylus parvae infecting rainbow trout (Oncorhynchus mykiss) and the invasive topmouth gudgeon (Pseudorasbora parva), respectively. The two circular genomes have a common genome organization found in other Gyrodactylus species. Comparative analyses of mitochondrial genomes from six Gyrodactylus species were carried out to determine base composition, codon usage, transfer RNA and ribosomal RNA genes, major non-coding regions, and nucleotide diversity within the genus. We also provide the first universal models of the secondary structures of rrnS and rrnL for this group thereby promoting utilization of these genetic markers. Universal primers provided herein can be used to obtain more mitochondrial information for pathogen identification and may reveal different levels of molecular phylogenetic inferences for this lineage.

Complete mitochondrial genomes for Icelus spatula, Aspidophoroides olrikii and Leptoclinus maculatus: pan-Arctic marine fishes from Canadian waters.

Abstract Three Arctic marine fishes Icelus spatula, Aspidophoroides olrikii and Leptoclinus maculatus have been identified as target species for investigating the effects of ocean warming on population patterns in high-latitude marine habitats around Canada. In preparation for this research, we have resolved whole mitochondrial genome sequences of 16u2009384, 17u2009200 and 16u2009384u2009bp for each species, respectively. GC content for each species was 47.5%, 44.2% and 45.3%, respectively. Mitogenome gene composition included 13 protein-encoding genes, 2 rRNA and 22 tRNA genes, for I. spatula and L. maculatus, consistent with other teleosts. Only 20 tRNA genes were annotated for A. olrikii, because tRNA-Pro and tRNA-Thr are poorly characterized and aberrantly located in this species.

Paragyrodactylus variegatus n. sp. (Gyrodactylidae) from Homatula variegata (Dabry De Thiersant, 1874) (Nemacheilidae) in central China.

Abstract:u2003 Paragyrodactylus variegatus n. sp. (Monogenea: Gyrodactylidae) is described from the fins and body surface of Homatula variegata (Dabry de Thiersant, 1874) living in cold-water streams in the Qinling Mountains of central China. It represents the third known species in the genus, with all species parasitizing Asian river loaches (Cypriniformes: Nemacheilidae). The new species resembles most closely Paragyrodactylus iliensis Gvosdev and Martechov, 1953, but is diagnosed by its marginal hooks being longer than 19 μm, a sickle longer than 4 μm, a sickle aperture shorter than the sickle distal width, and absence of a ventromedial indentation in the haptoral accessory hard part. Scanning electron microscopy reveals a central foramen in the haptoral accessory hard part, and small knob-like protuberances on the heel and toe of the marginal hook sickle. A partial 18S (448 bp) and complete ITS-1, 5.8S, and ITS-2 (1,139 bp) rDNA sequences are provided. A preliminary phylogenetic analysis based on the partial 18S gene, which included all sequenced genera of the Gyrodactylidae, suggests P. variegatus n. sp. is basal within Gyrodactylus sensu lato. It is proposed that the genus is a relict freshwater lineage parasitizing river loaches in the mountain plateaus of central Asia.

Gyrodactylus patersoni n. sp. (Monogenea: Gyrodactylidae) Infecting Atlantic Silverside (Menidia menidia) from Nova Scotia, Canada

Gyrodactylus patersoni n. sp. is described from the gills of the Atlantic silverside, Menidia menidia (L.) (Atherinidae), from Kingsport, Nova Scotia, Canada. The new species is the second species of Gyrodactylus to be reported from this host and is characterized by having small hamuli with short hamuli roots, a ventral bar with anterolateral processes of moderate size and a linguiform membrane, a dorsal bar with medial notch, and a male copulatory organ with 1 large spine and 5–6 terminal spines arranged in a single arched row. Gyrodactylus patersoni n. sp. most closely resembles Gyrodactylus stephanus Mueller, 1937 described from the mummichog, Fundulus heteroclitus L., from the northeastern coast of North America. The 2 species can be differentiated by the size of the hamuli (32.5 µm vs. 40.0 µm), length of the anterolateral processes (4.5 µm vs. 8.5 µm), number of copulatory spines (5–6 vs. 6–8) and, to a lesser degree, the shape of the marginal hook in that members of Gyrodactylus patersoni n. sp. have a slightly reduced heel and a more upright shaft. The description includes 438 sequenced base pairs (bp) of the 18S gene (including the V4 region) as well as 936xa0bp of the ITS region (ITS-1/5.8S/ITS-2). Basic Local Alignment Search Tool (BLAST) queries for the ITS and 18S fragments returned G. stephanus as most genetically similar (97.6% and 99.1%, respectively). Gyrodactylus patersoni n. sp. is a member of the Gyrodactylus arcuatus-group, a lineage that has successfully radiated through phylogenetically diverse fishes of the northern hemisphere, most of which share a littoral marine habitat.

Supplemental Description and Phylogenetic Placement of Gyrodactylus corti (Monogenea: Gyrodactylidae) Parasitizing Captive Wolf-Eel Anarrhichthys ocellatus in British Columbia

ABSTRACT: Gyrodactylus corti Mizelle and Kritsky, 1967, originally described from captive wolf-eel (Anarrhichthys ocellatus) in California, was rediscovered during an outbreak of gyrodactylosis among captive A. ocellatus at a marine research facility in Vancouver, British Columbia, Canada. The new material is used for a supplemental description of the parasite, including scanning electron microscopy of haptoral hard parts and molecular characterization of the internal transcribed spacer and partial 18S rDNA. The parasite is a member of Malmbergs Gyrodactylus perlucidus group, members of which have a marginal hook sickle with a distinct proximal base and distinct toe and ledge, anchors with a stout root and slender shaft and point, a ventral bar with medium-sized anterolateral processes and a prominent posterior membrane, and a male copulatory organ (MCO) with multiple rows of small spines that, for G. corti, are made up of spines of 2 distinct sizes, the smaller of the 2 occupying the outer row. This study suggests that this form of MCO is not homologous to the multi-rowed MCOs present in basal members of Gyrodactylus sensu lato and thus is independently derived. Related species, all from the North Atlantic Ocean and Baltic Sea, include G. perlucidus Bychowsky and Poljansky, 1953, from eelpout Zoarces viviparus and Z. v. elongates; Gyrodactylus errabundus Malmberg, 1970, also from Z. viviparous; and Gyrodactylus anarhichatis Mo and Lile, 1998, from Atlantic wolffish (Anarhichas lupus Ayres, 1855) and spotted wolffish (Anarhichas minor). These parasites all appear to be members of a clade within Gyrodactylus whose common ancestor likely infected an ancestral Anarhichadidae host in the Pacific, having expanded into the Atlantic during the late Cenozoic and eventually colonized species of Zoarcidae. Although not adopted taxonomically, the presented molecular phylogeny provides strong support for Malmbergs subgenus Paranephrotus and its species groups.

Infections of Gyrodactylus crysoleucas and Gyrodactylus sp. (Monogenea) at a Golden Shiner (Notemigonus crysoleucas) Farm in Minnesota

ABSTRACT: Infections of Gyrodactylus are reported at a Minnesota baitfish farm producing golden shiner (Notemigonus crysoleucas) in earthen ponds. Intensities reached approximately 100 parasites per fish, with no apparent sign of disease. Two species were present: Gyrodactylus crysoleucas Mizelle and Kritsky, 1967, was common (90% of the Gyrodactylus population), while an unidentified Gyrodactylus sp., morphologically resembling Gyrodactylus wellborni Nowlin, 1968, but not confirmed as such, was less so (10% of the Gyrodactylus population). We provide supplemental morphological and molecular diagnostic information on these understudied parasites. The 2 species of parasites are easily confused diagnostically with Gyrodactylus salmonis Yin and Sproston, 1948, and Gyrodactylus colemanensis Mizelle and Kritsky, 1967, from salmonid fishes in North America, but can be differentiated on the basis of differences in shape and size of the haptoral hard parts and provided 18S and ITS sequences. The case history is ...

Gyrodactylus laevisoides n. sp. (Monogenea: Gyrodactylidae) infecting northern redbelly dace Phoxinus eos Cope (Cyprinidae) from Nova Scotia, Canada.

Gyrodactylus laevisoides n. sp. is described from the gill rakers of red belly dace, Phoxinus eos Cope (Cyprinidae), from Nova Scotia, Canada. Gyrodactylus laevisoides n. sp. is the second species of Gyrodactylus Nordmann, 1832 described from this host and is characterised by weakly curving hamuli, a small ventral bar lacking anterolateral processes, stout dorsal bar, small marginal hooks with sickles larger proximally than distally and having a small circular process on the heel, a MCO with spines arranged in two arched rows, and lack of obvious excretory bladders. The new species most closely resembles Gyrodactylus laevis Malmberg, 1957, a Eurasian species whose principle host is Phoxinus phoxinus (L.). The two species are separated by Gyrodactylus laevisoides n. sp. having less divergent and longer hamulus root and marginal hook sickle toe with a steeper continuous angle and heel that is less prominent. The morphological description is supplemented with sequences of the 18S gene (449 bp, including the V4 region) and of the ITS region (821 bp). Gyrodactylus sedelnikowi Gvosdev, 1950 infecting Barbatula barbatula (L.) and Gyrodactylus neili Leblanc, Hansen, Burt & Cone, 2006 infecting Esox niger Lesueur are the most genetically similar species on GenBank for the 18S rRNA gene and ITS regions respectively (c.96% and c.92%). Gyrodactylus laevisoides n. sp. belongs to Malmberg’s subgenus Gyrodactylus (Gyrodactylus) and phylogenetic analysis of the ITS region groups this species with other members of the subgenus. The phylogeny has two main clades, one comprised of Eurasian species and the other of North American species, specifically Gyrodactylus laevisoides n. sp. and Gyrodactylus neili. It is suspected that this lineage, which is seemingly underrepresented in North America, likely colonised the new world with an ancestral species of Phoxinusvia the Bering land connection around the time of the Pliocene.