Morphology and taxonomic status of two little-known nematode species parasitizing North American fishes

Examination of some freshwater and brackishwater (estuarine) fishes in South Carolina in October 2009 yielded, in addition to other parasites, 2 little-known nematode species identified as Dichelyne fastigatus Chandler, 1935 (Cucullanidae), from the red drum, Sciaenops ocellatus (Linnaeus), from an estuary, and Rhabdochona ovifilamenta Weller, 1938 (Rhabdochonidae), from the shorthead redhorse, Moxostoma macrolepidotum (Lesueur), from Lake Moultrie. Light and scanning electron microscopy (the latter used for the first time for these species) made it possible to describe several important, but previously unreported, taxonomic features in D. fastigatus, such as the location of the excretory pore and deirids, the shape of deirids and a gubernaculum, the shape and size of eggs, the presence of precloacal ventral oblique muscle bands, and 11 pairs of caudal papillae and a pair of phasmids. It distinctly differs from the most similar Dichelyne cotylophora (Ward and Magath, 1917), a parasite of North American freshwater percids, in the number and arrangement of postanal papillae and by a markedly elevated cloacal region. Records of Dichelyne lintoni Barreto, 1922, from S. ocellatus probably concern D. fastigatus. Examination of R. ovifilamenta revealed a high degree of morphologic and biometric variability in this species. Based on our analysis, Rhabdochona laurentiana Lyster, 1940 , Rhabdochona milleri Choquette, 1951, and Rhabdochona catostomi Kayton, Kritsky, and Tobias, 1979, are synonymized with R. ovifilamenta Weller, 1938, typically a parasite of North American catostomids.     

Rabies in insectivorous bats of western Canada, 1979 to 1983

A total of 1,745, 362, and 536 bats collected in Alberta, British Columbia, and Saskatchewan, respectively, was tested for rabies virus between 1979 and 1983. Only one (0.1%) of 769 bats collected at random from buildings was infected with rabies virus in contrast to 95 (5%) of 1,874 symptomatic, rabies-suspect bats submitted for testing. The pattern of infection in the rabies-suspect bats was similar in Alberta and Saskatchewan, but differed in British Columbia. Rabies was diagnosed in four species of bats in each of Alberta and Saskatchewan, but in seven species in British Columbia. Annual prevalence in rabies-suspect bats was similar in colonial species within each province. Rabies was found rarely in suspect little brown bats (Myotis lucifugus) (less than 1%). In suspect big brown bats (Eptesicus fuscus), the prevalence was low in Saskatchewan (3%), moderate in Alberta (10%), and high in British Columbia (25%). Big brown bats accounted for over 55% of the rabid bats detected in each province. Annual prevalence reported in silver-haired bats (Lasionycteris noctivagans) and hoary bats (Lasiurus cinereus) was variable in all three provinces. Rabies is enzootic in northern insectivorous bats.     

Freshwater littoral copepods of British Columbia and Alberta (Canada)

This is part of an ongoing study on the freshwater littoral copepods of northwestern North America, comprising Alaska, Yukon, western Northwest Territories, British Columbia, Alberta, and Saskatchewan. In this paper we report 13 species of calanoids and 16 species of cyclopoids found in 142 samples collected from northern British Columbia and Alberta on either side of the Rocky mountains. We discuss morphology and distribution of some of these species.     

Review of Canadian species of the genera Gnathusa Fenyes,Mniusa Mulsant & Rey and Ocyusa Kraatz (Coleoptera,Staphylinidae, Aleocharinae)

Four species of Gnathusa Fenyes (G. alfacaribou Klimaszewski & Langor, G. caribou Lohse, G. eva Fenyes, and G. tenuicornis Fenyes) occur in the Nearctic and in Canada. Three species of Ocyusa Kraatz (O. asperula Casey, O. californica Bernhauer, O. canadensis Lohse), and three species of Mniusa Mulsant and Ray (M. minutissima (Klimaszewski & Langor), M. yukonensis (Klimaszewski & Godin), and M. odelli Klimaszewski & Webster, sp. n.), are known from the Nearctic and all but O. californica occur in Canada. The recently described Gnathusa minutissima Klimaszewski and Langor and Ocyusa yukonensis Klimaszewski and Godin, are transferred here to the genus Mniusa Mulsant & Rey. New provincial and state records are reported for: G. eva (Alberta), G. tenuicornis (Alberta, Oregon, and New Brunswick), O. canadensis (New Brunswick and Newfoundland), M. minutissima (New Brunswick), and M. yukonensis (Nova Scotia, New Brunswick, Quebec, and British Columbia). The female of M. yukonensis was discovered and is illustrated for the first time. The genus Mniusa is reported for the first time from Canada and represents the first confirmed generic record for North America. Keys for identification of all Canadian species, images of body and genital structures, maps showing distribution mainly in Canada, and new bionomics data are provided.     

Migratory songbirds disperse ticks across Canada, and first isolation of the Lyme disease spirochete, Borrelia burgdorferi, from the avian tick, Ixodes auritulus

During a 3-yr comprehensive study, 196 ixodid ticks (9 species) were collected from 89 passerine birds (32 species) from 25 localities across Canada to determine the distribution of avian-associated tick species and endogenous Lyme disease spirochetes, Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt, and Brenner. We report the following first records of tick parasitism on avian hosts: the rabbit-associated tick, Ixodes dentatus Marx, from Manitoba and Ontario; the mouse tick, Ixodes muris Bishopp and Smith, from British Columbia; and the blacklegged tick, Ixodes scapularis Say, from New Brunswick. Moreover, we provide the first record of the Neotropical tick, Amblyomma humerale Koch (1 nymph), in Canada and its parasitism of any bird. This tick was compared morphologically with nymphs of other Neotropical Amblyomma spp., and genetically, using a 344-bp fragment of the 12S rDNA sequence of 41 New World Amblyomma species. The first collections of the western blacklegged tick, Ixodes pacificus Cooley and Kohls, from passerine species in Alberta and British Columbia, are also reported. Notably, we further report the first isolation of B. burgdorferi from the bird tick, Ixodes auritulus Neumann, collected from an American robin, Turdus migratorius L., on Vancouver Island. Furthermore, B. burgdorferi-positive I. auritulus larvae were collected from a reservoir-competent fox sparrow, Passerella iliaca (Merrem). Our findings indicate that ground-dwelling passerines, in particular, are parasitized by certain ixodid ticks and play an important role across Canada in the wide dispersal of B. burgdorferi-infected ticks and increased risk of Lyme disease exposure.     

Redescription of Cystidicoloides fischeri based on specimens from piranhas in Brazil, and erection of a new genus (Nematoda: Cystidicolidae)

The cystidicolid nematode Cystidicoloides fischeri (Travassos, Artigas and Pereira, 1928) is redescribed from specimens collected from the stomach of the San Francisco piranha, Pygocentrus piraya (Cuvier), and the white piranha, Serrasalmus brandtii (Lütken) (both Characidae, Characiformes) (new host records), from the Três Marias Reservoir, Upper S?o Francisco River, Minas Gerais state, Brazil. The morphology of this type species of Cystidicoloides Skinker, 1931, studied with both light and scanning electron microscopy, is characterized by some taxonomically important, previously unreported features, such as the presence of a cephalic cuticular collarette, subdorsal and subventral cephalic spikes, cuticular tooth-like elevations inside the prostom, deirids, area rugosa, and details in the structure of the cephalic end. Heliconema izecksohni Fabio, 1982 is transferred to Cystidicoloides as C. izecksohni (Fabio, 1982) n. comb. Cystidicoloides uniseriata Valovaya and Valter, 1988 is considered a species inquirenda with uncertain generic appurtenance. The presence of subdorsal and subventral cephalic spikes and the collarette are characteristic of Cystidicoloides, comprising only species parasitizing Neotropical fishes. The species from salmonids in the Holarctic, hitherto reported mostly as Cystidicoloides ephemeridarum (Linstow, 1872), belongs to a different, newly erected genus, for which the name Salmonema n. gen. (type species S. ephemeridarum) is now proposed. Cystidicoloides prevosti (Choquette, 1951) is transferred to Salmonema as S. prevosti (Choquette, 1951) n. comb. Sterliadochona ssavini Skryabin, 1948 and Sterliadochona Skryabin, 1948 are considered as species inquirenda and a genus inquirendum, respectively. A key to species of Cystidicoloides is provided.     

Cultivation of Mediterranean species of Tuber (Tuberaceae) in British Columbia,Canada

Based on an assessment of soil and climatic conditions in British Columbia (BC), the Truffle Association of British Columbia (TABC) determined that the cultivation of Mediterranean Tuber melanosporum and Tuber aestivum might be possible in the warmer parts of the province. With the cooperation of independent truffle growers, TABC assessed the colonization of host tree roots collected from eight truffle orchards planted 2–7 years earlier using morphological and molecular criteria. Both Tuber species persisted on the roots of inoculated trees in six of the eight truffle orchards studied. The identity of Tuber ectomycorrhizas that had been characterized morphologically as differing from those of T. melanosporum and T. aestivum were determined using DNA sequence analysis to belong to three species of truffles native to the Pacific Northwest. One of those species, Tuber anniae, had been previously reported from BC, but the other two, Tuber menseri nom. prov. and Tuber beyerlei, are reported here from BC for the first time. Recently, production of three Périgord black truffles in one truffle orchard and one Burgundy truffle in another orchard demonstrates that these truffles are able to fruit in BC.     

Ecological factors drive differentiation in wolves from British Columbia

Aim Limited population structure is predicted for vagile, generalist species, such as the grey wolf (Canis lupus L.). Our aims were to study how genetic variability of grey wolves was distributed in an area comprising different habitats that lay within the potential dispersal range of an individual and to make inferences about the impact of ecology on population structure. Location British Columbia, Canada – which is characterized by a continuum of biogeoclimatic zones across which grey wolves are distributed – and adjacent areas in both Canada and Alaska, United States. Methods We obtained mitochondrial DNA control region sequences from grey wolves from across the province and integrated our genetic results with data on phenotype, behaviour and ecology (distance, habitat and prey composition). We also compared the genetic diversity and differentiation of British Columbia grey wolves with those of other North American wolf populations. Results We found strong genetic differentiation between adjacent populations of grey wolves from coastal and inland British Columbia. We show that the most likely factor explaining this differentiation is habitat discontinuity between the coastal and interior regions of British Columbia, as opposed to geographic distance or physical barriers to dispersal. We hypothesize that dispersing grey wolves select habitats similar to the one in which they were reared, and that this differentiation is maintained largely through behavioural mechanisms. Main conclusions The identification of strong genetic structure on a scale within the dispersing capabilities of an individual suggests that ecological factors are driving wolf differentiation in British Columbia. Coastal wolves are highly distinct and representative of a unique ecosystem, whereas inland British Columbia grey wolves are more similar to adjacent populations of wolves located in Alaska, Alberta and Northwest Territories. Given their unique ecological, morphological, behavioural and genetic characteristics, grey wolves of coastal British Columbia should be considered an Evolutionary Significant Unit (ESU) and, consequently, warrant special conservation status. If ecology can drive differentiation in a highly mobile generalist such as the grey wolf, ecology probably drives differentiation in many other species as well.     

High genetic diversity in the blue-listed British Columbia population of the purple martin maintained by multiple sources of immigrants

To assess genetic diversity in the blue-listed purple martin (Progne subis) population in British Columbia, we analysed mitochondrial control region sequences of 93 individuals from British Columbia and 121 individuals collected from seven localities of the western and eastern North American subspecies P. s. arboricola and P. s. subis, respectively. Of the 47 haplotypes we detected, 34 were found exclusively in western populations, and 12 were found only in eastern populations. The most common eastern haplotype (25) was also found in three nestlings in British Columbia and one in Washington. Another British Columbia nestling had a haplotype (35) that differed by a C to T transition from haplotype 25. Coalescent analysis indicated that these five nestlings are probably descendents of recent immigrants dispersing from east to the west, because populations were estimated to have diverged about 200,000–400,000 ybp, making ancestral polymorphism a less likely explanation. Maximum likelihood estimates of gene flow among all populations detected asymmetrical gene flow into British Columbia not only of rare migrants from the eastern subspecies in Alberta but also a substantial number of migrants from the adjacent Washington population, and progressively lower numbers from Oregon in an isolation-by distance pattern. The influx of migrants from different populations is consistent with the migrant-pool model of recolonization which has maintained high genetic diversity in the small recovering population in British Columbia. Thus, the risk to this population is not from genetic erosion or inbreeding following a severe population crash, but from demographic stochasticity and extinction in small populations.     

Observations on two Rhabdochona species (Nematoda: Rhabdochonidae) from freshwater fishes in Argentina, including description of Rhabdochona fabianae n. sp

Helminthological examination of specimens of the freshwater fishes Bryconamericus iheringi Boulenger, 1887 (Characidae) and Jenynsia multidentata (Jenyns, 1842) (Anablepidae), collected from Medina River, Province of Tucuman, Argentina, revealed the presence of 2 species of parasitic nematodes, Rhabdochona fabianae n. sp. and Rhabdochona acuminata (Molin, 1860) (Rhabdochonidae). Rhabdochona fabianae n. sp. was characterized by the presence of 16 anterior teeth in the prostom and filamented eggs in females. Rhabdochona acuminata was recorded for the first time in the north of Argentina.     

Temperature and host-plant effects on development and population growth of Mecinus janthinus (Coleoptera: Curculionidae), a biological control agent for invasive Linaria spp.

Mecinus janthinus Germar is a European stem-mining weevil that has been established in North America as a biological control agent against the invasive European weeds Linaria vulgaris P. Mill. and Linaria dalmatica (L.) P. Mill. (Scrophulariaceae). Establishment success and impact of the weevil have varied widely among sites. We investigated the hypothesis that some of this variation may be due to a lack of sufficient time for M. janthinus to develop to the adult (overwintering) stage in less favorable climates. Development time of M. janthinus was measured in L. vulgaris and L. dalmatica at four constant temperatures, and logistic regression was used to derive a model for the effect of temperature on development. Development rates were simulated using historic climate data for a site in central Alberta (where establishment was marginal on L. vulgaris) and one in southern British Columbia (where outbreaks occurred, resulting in heavy damage to L. dalmatica). The model showed that, on average, the British Columbia site had 50 more days available for the weevil to lay eggs that could reach the adult stage in time for overwintering than did the Alberta site. This may explain the more rapid population buildup at the British Columbia site. This model could be used to predict the climatic suitability of other areas for establishment of M. janthinus. An unexplained result was the very low survival rate of eggs laid in L. dalmatica under the same experimental conditions.     

Phytosociological,bioclimatic and biogeographical classification of woody climax communities of western North America

Abstract. In this study, combining the Braun-Blanquet phytosociological approach with numerical methods (cluster analysis and principal coordinate ordination), woody climax associations of western North America are described, ranging from NW Baja California (Mexico) to Alaska (USA), and including some interior zones of Idaho and Montana (USA), Alberta, British Columbia and the Yukon Territory (Canada). 95 floristic associations are identified, and each is characterized by floristic combination, biogeographical range, and bioclimatic conditions.     

The genetic legacy of extirpation and re-colonization in Vancouver Island wolves

Hybridization between wild and domestic species is of conservation concern because it can result in the loss of adaptations and/or disappearance of a distinct taxon. Wolves from Vancouver Island, British Columbia (Canada), have been subject to several eradication campaigns during the twentieth century and were considered virtually extirpated between 1950 and 1970. In this study, we use control region mitochondrial DNA sequences and 13 autosomal microsatellite loci to characterize Vancouver Island wolves as well as dogs from British Columbia. We observe a turnover in the haplotypes of wolves sampled before and after the 1950–1970 period, when there was no permanent wolf population on the island, supporting the probable local extinction of wolves on Vancouver Island during this time, followed by re-colonization of the island by wolves from mainland British Columbia. In addition, we report the presence of a domestic dog mtDNA haplotype in three individuals eliminated in 1986 that were morphologically identified as wolves. Here we show that Vancouver Island wolves were also identified as wolves based on autosomal microsatellite data. We attribute the hybridization event to the episodically small size of this population during the re-colonization event. Our results demonstrate that at least one female hybrid offspring, resulting from a cross of a male wolf and a female dog or a female hybrid pet with dog mtDNA, successfully introgressed into the wolf population. No dog mtDNA has been previously reported in a population of wild wolves. Genetic data show that Vancouver Island wolves are distinct from dogs and thus should be recognized as a population of wild wolves. We suggest that the introgression took place due to the Allee effect, specifically a lack of mates when population size was low. Our findings exemplify how small populations are at risk of hybridization.     

Age and growth of big skate (Raja binoculata) and longnose skate (R. rhina) in the Gulf of Alaska

In 2003, big skates, Raja binoculata, and longnose skates, Raja rhina, were the target of a commercial fishery around Kodiak Island in the Gulf of Alaska (GOA) for the first time. The sudden development of a fishery for these species prompted the need for improved life history information to better inform fishery managers. Due to the selective nature of the skate fishery, mostly larger individuals were captured. Back-calculation from skate vertebral measurements was used to estimate size-at-age for younger skates. Because back-calculated age-length data within individuals were highly correlated, bootstrap resampling methods were used to test for differences between male and female growth curves. Results from bootstrapping indicated that differences between male and female growth were statistically significant for both species. This investigation indicates that growth of big skates in the GOA (max size 178 cm total length, max age 15 years) is similar to that in California, but different from that in British Columbia. For longnose skates, our GOA results agree with those reported in British Columbia, but were considerably older (max size 130 cm, max age 25 years) than those reported in California, which may not be surprising because longnose skates in the present study were generally larger. This life history information suggests that both big and longnose skates are at risk of unsustainable exploitation by targeted fisheries.     

Intestinal helminths of some Nile fishes near Cairo, Egypt with redescriptions of Camallanus kirandensis Baylis 1928 (Nematoda) and Bothriocephalus aegyptiacus Rysavy and Moravec 1975 (Cestoda)

Of 10 species of Nile fishes collected during the summer of 1975 at Giza near Cairo, Egypt, 7 harbored 7 helminth species. Recovered material includes 3 species of nematodes: Camallanus kirandensis Baylis 1928 (new host and geographical record), Cucullanus barbi Baylis 1923, and Rhabdochona congolensis Campana-Rouget 1961 (new host record); three species of cestodes: Khawia sp. (new in Africa), Polyonchobothrium clarias (Woodland 1925) Meggitt 1930, and Bothriocephalus aegyptiacus Rysavy and Moravec 1975; and one acanthocephalan species, Acanthosentis tilapiae Baylis 1947 (new geographical record). Morphologic observations of each species are reported. C. kirandensis and B. aegyptiacus are redescribed.     

The High River Microblade Industry,Alberta

Abstract

A small collection of obsidian and chalcedony microblades, from a site near Calgary, Alberta, is described and compared with other microblades from the Plains and from the Plateau. Although the age and cultural affiliations of the micro blades are not certain, there is some evidence to suggest that they are early in the Plains sequence. The microblades have some distinctive attributes including ridge flakes, for which a typology is suggested. A comparison of the High River microblades with a large sample from the Interior Plateau of British Columbia suggests that the stimulus for the Alberta micro blades did not derive from the Plateau.     

Characterization of Environmental Sources of the Human and Animal Pathogen Cryptococcus gattii in British Columbia, Canada, and the Pacific Northwest of the United States

Cryptococcus gattii has recently emerged as a primary pathogen of humans and wild and domesticated animals in British Columbia, particularly on Vancouver Island. C. gattii infections are typically infections of the pulmonary and/or the central nervous system, and the incidence of infection in British Columbia is currently the highest reported globally. Prior to this emergence, the environmental distribution of and the extent of colonization by C. gattii in British Columbia were unknown. We characterized the environmental sources and potential determinants of colonization in British Columbia. C. gattii was isolated from tree surfaces, soil, air, freshwater, and seawater, and no seasonal prevalence was observed. The C. gattii concentrations in air samples were significantly higher during the warm, dry summer months, although potentially infectious propagules (<3.3 μm in diameter) were present throughout the year. Positive samples were obtained from many different areas of British Columbia, and some locations were colonization “hot spots.” C. gattii was generally isolated from acidic soil, and geographic differences in soil pH may influence the extent of colonization. C. gattii soil colonization also was associated with low moisture and low organic carbon contents. Most of the C. gattii isolates recovered belonged to the VGIIa genetic subtype; however, sympatric colonization by the VGIIb strain was observed at most locations. At one sampling site, VGIIa, VGIIb, VGI, and the Cryptococcus neoformans serotype AD hybrid all were coisolated. Our findings indicate extensive colonization by C. gattii within British Columbia and highlight an expansion of the ecological niche of this pathogen.