| gametogenesis and fertilization in rhabdias ranae walton 1929: i. the parasitic hermaphrodite. | the somatic, diploid, and haploid chromosome numbers were determined in the hermaphrodite (24, 12, eggs 6, spermatozoa 5 or 6). oocytes in the ovary synapsis zone contain 6 tetrads. the tetrads seem to disappear in the growth zone and reappear in the oocyte just prior to fertilization. after sperm penetration, the tetrads move to the periphery and form 2 polocytes by rapid meiotic divisions. spermatogenesis occurs in the testis zone. primary spermatocytes show 5 large tetrads and 2 small heteroc ... | 1978 | 570219 |
| helminths of two native frog species (rana chiricahuensis, rana yavapaiensis) and one introduced frog species (rana catesbeiana) (ranidae) from arizona. | the gastrointestinal tracts, lungs, urinary bladders, and body cavities of rana catesbeiana (n = 25), rana chiricahuensis (n = 25), and rana yavapaiensis (n = 37) from arizona were examined for helminths. helminths representing 9 species of trematodes: cephalogonimus brevicirrus, glypthelmins quieta, gorgoderina attenuata, haematoloechus complexus, haematoloechus langiplexus, megalodiscus temperatus, alaria sp., clinostomum sp., and an unidentified strigeid; and 4 species of nematodes: falcaustr ... | 1998 | 9488361 |
| a new species of rhabdias from lungs of the wood frog, rana sylvatica, in north america: the last sibling of rhabdias ranae? | rhabdias bakeri n. sp. is described from specimens found in lungs of the wood frog, rana sylvatica, from north dakota. the new species has previously been mistakenly identified as rhabdias ranae walton, 1929, a common parasite of the leopard frog, rana pipiens. the new species differs from r. ranae and rhabdias joaquinensis ingles, 1935 by the shape and size of pseudolabia, shape and size of buccal capsule, and wider esophageal bulb. molecular analysis based on the partial sequences of nuclear 1 ... | 2006 | 16884011 |
| host specificity of north american rhabdias spp. (nematoda: rhabdiasidae): combining field data and experimental infections with a molecular phylogeny. | lungworms of the cosmopolitan genus rhabdias are among the most common parasites of amphibians and squamate reptiles. the present study used experimental infections, field studies, and a molecular phylogeny to determine the host specificity of 6 rhabdias spp. that infect snakes and anurans from north america. the molecular phylogeny suggests rhabdias ranae from nebraska and mississippi may represent separate, cryptic species. in addition, the phylogeny strongly supports separate clades for anura ... | 2013 | 22988815 |
| patterns of infection by lungworms, rhabdias ranae and haematoloechus spp., in northern leopard frogs: a relationship between sex and parasitism. | we examined a population of northern leopard frogs to determine whether sex biases in investment in immunity, previously reported for this host species under controlled exposures to lung nematodes, is predictive of patterns of parasitism in nature. we examined rhabdias ranae and haematoloechus spp. infections in 74 breeding adult, 28 non-breeding adult, and 53 juvenile frogs. contrary to our predictions, r. ranae prevalence and mean abundance were higher in breeding female frogs (prevalence: 39. ... | 2009 | 18712948 |
| effects of agricultural pesticides on the immune system of rana pipiens and on its resistance to parasitic infection. | in the past 30 years, many amphibian species have suffered population declines throughout the world. mass mortality have been frequently reported, and in several instances, infectious diseases appear to be the cause of death. the role that contaminants could play in these die-offs through immunotoxic effects has been poorly investigated. in this study, juvenile leopard frogs (rana pipiens) were exposed for 21 d to a mixture of six pesticides (atrazine, metribuzin, aldicarb, endosulfane, lindane, ... | 2003 | 12729224 |
| exposure of leopard frogs to a pesticide mixture affects life history characteristics of the lungworm rhabdias ranae. | we tested the hypothesis that exposure of leopard frogs ( rana pipiens) to agricultural pesticides can affect the infection dynamics of a common parasite of ranid frogs, the lungworm rhabdias ranae. after a 21-day exposure to sublethal concentrations of a pesticide mixture composed of atrazine, metribuzin, aldicarb, endosulfan, lindane and dieldrin, or to control solutions (water, dimethyl sulfoxide), parasite-free juvenile frogs were challenged with 30 infective larvae of r. ranae. approximatel ... | 2003 | 12721838 |
| falcaustra lowei n. sp. and other helminths from the tarahumara frog, rana tarahumarae (anura: ranidae), from sonora, mexico. | seventy-four specimens of falcaustra lowei n. sp. were recovered from the intestines of 9 of 42 (21%) tarahumara frogs. rana tarahumarae, from sonora, mexico. f. lowei is the 14th nearctic species to be described and belongs to that group of species possessing a pseudosucker, namely f. catesbeianae, f. chabaudi, f. chelydrae, f. mexicana, and f. wardi. the new species can be readily differentiated from these by the arrangement of caudal papillae and length of spicules. priority description of f. ... | 2001 | 11318564 |
| nematode lungworms of two species of anuran amphibians: evidence for co-adaptation. | genetic studies have indicated that some parasite species formerly thought to be generalists are complexes of morphologically similar species, each appearing to specialize on different host species. studies on such species are needed to obtain ecological and parasitological data to address whether there are fitness costs in parasitizing atypical host species. we examined whether lungworms from two anuran host species, lithobates sylvaticus and lithobates pipiens, differed in measures of infectio ... | 2008 | 18572173 |
| rhabdias kongmongthaensis sp. n. (nematoda: rhabdiasidae) from polypedates leucomystax (amphibia: anura: rhacophoridae) in thailand. | rhabdias kongmongthaensis sp. n. is described based on specimens found in the lungs of the tree frog polypedates leucomystax (gravenhorst) (amphibia: rhacophoridae) from kanchanaburi province, western thailand. the new species is similar to two north-american species, rhabdias ranae and r. americanus, by presence of two lateral pseudolabia, each with two inner submedian protuberances. r. kongmongthaensis differs from both species by relative length and shape of the tail, and by its distribution ... | 2005 | 16405297 |
| rates of development in male and female wood frogs and patterns of parasitism by lung nematodes. | researchers are becoming interested in testing whether investment in growth and/or development trades off against investment in parasite defence. we tested this idea by examining relations between development of wood frogs (rana sylvatica) and susceptibility to lung nematodes (rhabdias ranae). male and female frogs reared in outdoor mesocosms were the same length and mass at metamorphosis. however, males metamorphosed sooner than females. lung nematodes were no more likely to penetrate male vers ... | 2008 | 17991306 |