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Papers by David Gibson

Parasitology, Feb 28, 2007

Didymobothrium rudolphii (Cestoda : Spathebothriidea) was collected seasonally from the sand sole... more Didymobothrium rudolphii (Cestoda : Spathebothriidea) was collected seasonally from the sand sole, Solea lascaris, off the northern, central and southern areas of the Portuguese coast. Morphological and molecular analyses were conducted in order to examine the possible existence of cryptic species and to facilitate the circumscription of their morphological boundaries. Data were compared between D. rudolphii specimens from each of the 3 geographical areas and 4 seasons, and principal components analysis of 18 morphological characters was used to detect differences. Two distinct genotypes were present with sequence divergences of 1. 9% and 2. 1% in the large subunit (lsrDNA) and second internal transcribed spacer (ITS-2) of ribosomal DNA (rDNA), respectively. The less common ' central' genotype was present only off the central area from summer to winter, whereas the ' common ' genotype was present throughout the year off the northern and southern areas, but only during spring in the central area. No sequence variation was found within each genotype. The presence of 2 distinct genetic entities was supported by morphological analyses, which showed the ' central ' genotype specimens to be more slender and elongate, although morphometric ranges overlapped considerably for most characters. Molecular phylogenetic analysis of 4 of the 5 known genera of the Spathebothriidea showed Spathebothrium to be the earliest branching lineage and the 2 genotypes of Didymobothrium formed a sister group to Cyathocephalus. The concordance of genetic differences with variation in host diet according to season and locality could account for sympatric speciation occurring in the central region of the Portuguese coast.

Journal of fish diseases, Jan 18, 2016

In parasite surveys of fishes from Lake Balaton and its tributaries in Hungary, infections with m... more In parasite surveys of fishes from Lake Balaton and its tributaries in Hungary, infections with metacercariae of a species of the digenean genus Echinochasmus (Trematoda: Echinostomatidae) were found in seven species of fish. In ruffe, Gymnocephalus cernuus, malformations of the gill filaments apparently caused by these infections were observed. These malformations were in the form of bifurcations of the filaments at about their mid-length. At the point where the filaments bifurcate, an Echinochasmus metacercaria was always embedded in the cartilaginous ray of the gill filament. All specimens of the ruffe were found to be infected by these metacercariae, and each ruffe specimen was infected by 30-300 metacercariae. Such a bifurcation was found in all of the ruffe specimens, but, apart from these gill malformations, the metacercariae produced only local changes in the cartilage. In the other six infected fish species, only local signs were observed in the cartilage. Experimental infe...

Parasite, 2021

This is the first study assessing the cytoarchitecture of the vitellarium of members of the fresh... more This is the first study assessing the cytoarchitecture of the vitellarium of members of the freshwater, teleost-infecting lineage of blood-flukes (Aporocotylidae). The vitelline cytoarchitecture of two innominate species of Sanguinicola from freshwater fishes in Russia showed that vitelline cells at different stages of maturation are widely distributed throughout much of the body and are mixed with other cell types. The latter feature indicates that use of the term “follicular vitellarium” is inappropriate for species of this genus. An additional characteristic of the vitelline cells in these Sanguinicola spp. is their ability to form long, pseudopodia-like extensions of the peripheral cytoplasm that contact neighbouring vitelline cells and sarcoplasmic extensions, forming both heterologous and homologous intercellular junctions. Within the vitelline duct lumen, the cytoplasm of mature vitelline cells is filled with regular clusters (0.5–1.0 μm in diameter), comprising 10–30 vitelli...

Folia Parasitologica

The life-history of Mazocraes alosae Hermann, 1782 on one of its hosts, the Pontic shad Alosa imm... more The life-history of Mazocraes alosae Hermann, 1782 on one of its hosts, the Pontic shad Alosa immaculata Bennett, is described for the first time. This anadromous fish, which occurs off the coast of the Crimea and migrates from the Black Sea to the Sea of Azov and into the River Don for spawning, was studied throughout its migration and during all seasons. It is demonstrated that the period of reproduction of this monogenean is significantly longer than that reported for the population in the Caspian Sea, lasting from April to November with a peak in April-May, and continues both in the sea and the river. Experiments showed that water salinity does not limit the development of the eggs or the hatching of the oncomiracidia. Our data reveal that the abundance of M. alosae is not determined by the size or sex of mature fish and that shad of less than two years old can also be infected with this monogenean, although less frequently than older fish. The direction of the migration of A. immaculata, either from the Black Sea to the Sea of Azov and into the rivers or in the opposite direction, does not influence the number of monogeneans present on the host. The main factor affecting the dynamics of the abundance of this monogenean is season, and, as has been indicated previously in the Caspian Sea basin, there is a synchronisation between the parasite's life-history and both the host's spawning behaviour and the duration of its migration.

Zoologica Scripta, 1994

ABSTRACT

Systematic Parasitology, 2010

Four new and one unidentified species of Neohaliotrema Yamaguti, 1965 were obtained from the gill... more Four new and one unidentified species of Neohaliotrema Yamaguti, 1965 were obtained from the gills of the Indo-Pacific sergeant Abudefduf vaigensis (Quoy & Gaimard) off Pulau Langkawi, Malaysia. The five species, N. malayense n. sp., N. bombini n. sp., N. andamanense n. sp., N. parvum n. sp. and an unidentified Neohaliotrema sp. (similar to N. macracanthum Zhukov, 1976), are described and distinguished based mainly on features of the haptor. Species of this genus are divisible into two groups, the 'maomao group', with two pairs of morphometrically modified 'marginal' hooks and a fenestrated haptor, and the 'gracile group', with morphologically similar marginal hooks and an entire haptor. With the exception of N. bombini n. sp., the species described fit within the 'maomao group'. It is suggested that the more complex Neohaliotrema species of the 'maomao group' have modified hooks 1 and 2 on a haptoral 'isthmus' between two large apertures, i.e. 'windows', whereas the less complex species lacking these features are those of the 'gracile group'. Neohaliotrema spp. have only a single pair of pigmented eye-spots. A fenestrated haptor is unique to the Neohaliotrema spp. of the 'maomao group'. The generic diagnosis of Neohaliotrema is amended to include new data and a key to its known species is presented.

Systematic Parasitology, 1999

The genera Sinineobucephalopsis and Sinogastromyzontrema are diagnosed and placed in the family U... more The genera Sinineobucephalopsis and Sinogastromyzontrema are diagnosed and placed in the family Urotrematidae. Sinineobucephalopsis macrocirrus is redescribed from Glyptothorax fokiensis in Guangdong and Hunan provinces. Urotrema glyptothoraci is considered synonymous with Sinineobucephalopsis macrocirrus. The new combinations Sinineobucephalopsis postlecitha, Sinineobucephalopsis proeilecitha and Sinineobucephalopsis sinipercae are formed for species originally placed in Urotrema and Urotrematulum. Sinogastromyzontrema guangxiensis is redescribed from Sinogastromyzon wui in Guangxi Province. Urotrema parallelorchis is considered a synonym of Sinogastromyzontrema guangxiensis. A key to the species or species-complexes in the family Urotrematidae is given.

Systematic Parasitology, 2009

Sundatrema langkawiense n. g., n. sp. (Monogenea: Ancyrocephalidae) is described from the gills o... more Sundatrema langkawiense n. g., n. sp. (Monogenea: Ancyrocephalidae) is described from the gills of the orbfish Ephippus orbis (Bloch) (Ephippidae) off the Island of Langkawi, Malaysia, in the Andaman Sea. This new genus has the ancyrocephalid characteristics of four anchors, 14 marginal hooks and two bars, but differs from other four-anchored monogenean genera, and notably from Parancylodiscoides Caballero & Bravo Hollis, 1961 (found on the ephippids Chaetodipterus spp. off Central and South America), by having a unique combination of features. These include a muscular genital sucker and a vas deferens and vagina on the same (sinistral) side of the body. It is similar to Parancylodiscoides in having four haptoral reservoirs opening at the anchoral apertures, four anchors, similar connecting bars and small marginal hooks. The new species is characterised by the above generic features and by possessing a small, short copulatory organ lacking an accessory piece.

ZooKeys, Feb 26, 2015

The acanthocephalan genus Echinorhynchus Zoega in Müller, 1776 (sensu Yamaguti 1963) is a large a... more The acanthocephalan genus Echinorhynchus Zoega in Müller, 1776 (sensu Yamaguti 1963) is a large and widespread group of parasites of teleost fish and malacostracan crustaceans, distributed from the Arctic to the Antarctic in habitats ranging from freshwaters to the deep-sea. A total of 52 species are currently recognised based on the conventional morphological species concept; however, the true diversity in the genus is masked by cryptic speciation. The considerable diversity within Echinorhynchus is an argument for subdividing the genus if monophyletic groups with supporting morphological characters can be identified. With this objective in mind, partial sequences of two genes with different rates of evolution and patterns of inheritance (nuclear 28S rRNA and mitochondrial cytochrome c oxidase subunit I) were used to infer the phylogenetic relationships among eight taxa of Echinorhynchus. These included representatives of each of three genus group taxa proposed in a controversial revision of the genus based on cement gland pattern, namely Echinorhynchus (sensu stricto),

Zoologica Scripta, 1987

The otariid seal parasite Contracaecum ogmorhini Johnston & Mawson, 1941 is redescribed based... more The otariid seal parasite Contracaecum ogmorhini Johnston & Mawson, 1941 is redescribed based upon new material and the type specimens. The geographical records of this species indicate that it has an antiboreal circumpolar distribution with an isolated population on ...

Annales Zoologici Fennici, 1997

These parasites were found to infect the following: 21 of 25 fish species, some of which were mar... more These parasites were found to infect the following: 21 of 25 fish species, some of which were marine, studied in the oligohaline, brackish waters of the Bothnian Bay, Baltic Sea; all nine fish species studied from a large, oligotrophic lake in NE Finland (Yli-Kitka); and all five studied fish species in a small, hypereutrophic lake (Kuivasjärvi). Diplostomids in the lens of the fishes of the Bothnian Bay, studied during two periods extending over seven years, suggest the presence of a stable and predictable system, despite the extremely narrow transmission window between the first (snail) and second (fish) intermediate hosts. Diplostomids in the lens of fishes from the Bothnian Bay and Lake Kuivasjärvi predominated (> 50% infection in 14 of 21 species) over those from the vitreous body of the eye in most cases, but were much lower (< 18%) in Lake Yli-Kitka. The situation in the vitreous body was quite the reverse, since diplostomids in this site predominated over those in the lens in fishes of Lake Yli-Kitka (> 80% prevalences in five of nine fish species). This difference is considered to be dependent on differences in the piscivorous bird fauna. The fact that diplostomid metacercariae accumulated in the fish, together with the lack of any real seasonal variation, confirms the longevity of these larvae in their fish intermediate hosts. Thus metacercariae form a reservoir which is mainly responsible for the maintenance of diplostomid suprapopulations in these northern latitudes.

Acta Parasitologica, 2011

Vitellogenesis and vitellocytes of the bothriocephalidean cestode Clestobothrium crassiceps (Rudo... more Vitellogenesis and vitellocytes of the bothriocephalidean cestode Clestobothrium crassiceps (Rudolphi, 1819), a parasite of the teleost fish Merluccius merluccius (L., 1758), were studied by means of transmission electron microscopy (TEM) and cytochemistry. During vitellogenesis, four developmental stages were distinguished at the TEM level: (I) a stem cell stage of the gonial type; (II) an early differentiation stage, predominantly exhibiting lipid and protein synthetic activity; (III) an advanced differentiation or vitellocyte maturation stage, primarily exhibiting active glycogenesis still accompanied by an increase in lipid accumulation; and (IV) a mature vitellocyte stage. Vitellogenesis involves: (1) an increase in cell volume; (2) an extensive development of parallel, frequently concentrically arranged, cisternae of granular endoplasmic reticulum (GER) that produce dense, proteinaceous shell-gobules; (3) the development of Golgi complexes engaged in the packaging of this mate...

Fauna Europaea provides a public web-service with an index of scientific names (including importa... more Fauna Europaea provides a public web-service with an index of scientific names (including important synonyms) of all living European land and freshwater animals, their geographical distribution at country level (up to the Urals, excluding the Caucasus region), and some additional information. The Fauna Europaea project covers about 230,000 taxonomic names, including 130,000 accepted species and 14,000 accepted subspecies, which is much more than the originally projected number of 100,000 species. This represents a

Annales de Parasitologie Humaine et Comparée, 1989

Wardula sarguicola n. sp. is reported from the rectum of Diplodus sargus off the western coast of... more Wardula sarguicola n. sp. is reported from the rectum of Diplodus sargus off the western coast of Corsica (the Scandola Nature Reserve). It is the only mesometrid species which has been recorded from a fish other than Sarpa salpa. Among the numerous features which dis tinguish W. sarguicola n. sp. from W. capitellata (Rud.), the type and only other species of the genus, we draw special attention to its smaller size, the absence of buccal ridges within the oral sucker, the presence of uterine coils between the gonads and even posterior to the ovary, a well-developed prostatic sac and a genital pore remote from the oral sucker.

Parasites & Vectors, 2009

Publish with Bio Med Central and every scientist can read your work free of charge "BioMed Centra... more Publish with Bio Med Central and every scientist can read your work free of charge "BioMed Central will be the most significant development for disseminating the results of biomedical researc h in our lifetime."

Parasite, 1997

The morphology of three Palaearctic species of the genus Petasiger Dietz, 1909, parasitizing greb... more The morphology of three Palaearctic species of the genus Petasiger Dietz, 1909, parasitizing grebes and exhibiting a significant degree of overlap, was studied. Ninety-three specimens belonging to P. grandivesicularis, P. neocomense and P. pungens were compared using univariate and multivariate statistical analyses of 17 metrical characters. A stepwise discriminant analysis run in three variants and based on seven variables (body length, body width, oral sucker diameter, pharynx diameter, ventral sucker diameter, posterior testis diameter and oesophagus length) yielded a 100 % accurate classification. The first canonical discriminant function separated specimens belonging to P. grandivesicularis and P. pungens, and the second function effectively differentiated the P. neocomense sample. Two variables (pharynx diameter and oesophagus length] were strongly correlated with the canonical functions and, when used alone, discriminated the three Petasiger spp. A simple key based on two variables used in the discriminant analyses and a table of the qualitative and quantitative characters used for the identification of the three species are presented.

Helminthologia, 2007

A male specimen of Dracunculus (Nematoda: Dracunculidae), collected in 1973 from the lung of the ... more A male specimen of Dracunculus (Nematoda: Dracunculidae), collected in 1973 from the lung of the Papuan olive python Apodora papuana (Peters et Doria) and now deposited in the helminthological collection of the Natural History Museum in London, is identified as Dracunculus mulbus Jones et Mulder, 2007, a species recently described from the water python Liasis fuscus Peters in northern Australia. Apodora papuana is a new host record for D. mulbus and Papua New Guinea is apparently a new geographical record.

Biological Conservation, 2007

look a core characteristic of biodiversity, i.e. the large number of narrow-range species and the... more look a core characteristic of biodiversity, i.e. the large number of narrow-range species and their intrinsic vulnerability. With ill-selected indicator species, the extinction of narrowrange endemics would go unnoticed.