| effect of temperature on water and ion balance in larval ambystoma gracile. | | 1968 | 5689524 |
| developmental responses of amphibians to solar and artificial uvb sources: a comparative study. | many amphibian species, in widely scattered locations, currently show population declines and/or reductions in range, but other amphibian species show no such declines. there is no known single cause for these declines. differential sensitivity to uvb radiation among species might be one contributing factor. we have focused on amphibian eggs, potentially the most uvb-sensitive stage, and compared their resistance to uvb components of sunlight with their levels of photolyase, typically the most i ... | 1996 | 8806225 |
| localization of the pituitary lactotropes and thyrotropes within ambystoma gracile by histochemical and immunochemical methods. a developmental study of two populations. | the prolactin-producing cells are the first hormone-producing cells of the pars distalis to be differentiated within ambystoma gracile. they first appear when the larvae attain a length of approximately 3.0 cm snout to vent length (svl). thyrotropes are observed as the next chromophilic cells to appear, and they occur when the larvae are approximately 4.5 cm svl. both thyrotropes and lactotropes increase in numbers until metamorphosis. gonadotropes begin to appear when larvae attain a size of 5. ... | 1978 | 352530 |
| ontogeny of the hyobranchial apparatus in the salamanders ambystoma talpoideum (ambystomatidae) and notophthalmus viridescens (salamandridae): the ecological morphology of two neotenic strategies. | comparison of metamorphosis of skull and hyobranchial system in two species of neotenic salamanders reveals two different types of neoteny. ambystoma talpoideum is completely neotenic owing to delayed metamorphosis. notophthalmus viridescens exhibits limited neoteny as a result of incomplete metamorphosis. morphological details of neoteny are compared to life history in both species in order to discuss the ecological morphology of the two neotenic strategies. comparisons to taricha granulosa, tr ... | 1987 | 29921111 |
| a new species of trypanosome from the salamander ambystoma gracile, with notes on a collection of amphibian blood smears. | | 1954 | 13212540 |
| effect of salt depletion on hydromineral balance in larval ambystoma gracile. i. ionic composition. | | 1970 | 5440937 |
| effect of salt depletion on hydromineral balance in larval ambystoma gracile. ii. kinetics of ion exchange. | | 1970 | 5440938 |
| environmental factors and the incidence of neoteny in ambystoma gracile (baird) (amphibia: caudata). | | 1974 | 4442000 |
| temperature effect on sodium and chloride movements in larval ambystoma gracile. | | 1975 | 234047 |
| factors affecting the larval growth and development of laboratory-reared ambystoma gracile (baird) from natural populations of different temperature regimes. | temperature-transfer of ambystoma gracile larvae from 11 degrees c to 21 degrees c does not significantly alter growth rates at the higher temperature when compared to larvae continuously grown at 21 degrees c. temperature-transfer does not alter the incidence of neoteny within populations, even though interpopulation neotenic tendencies differ. salamander larvae from the high altitude population exhibit larvae from the high altitude population exhibit faster growth rates than the larvae reared ... | 1978 | 757513 |
| impact of guthion on survival and growth of the frog pseudacris regilla and the salamanders ambystoma gracile and ambystoma maculatum. | the effects of the insecticides guthion (technical grade) and guthion 2s (commercial formulation) on survival and growth of tadpoles of the pacific treefrog pseudacris regilla, and larvae of the northwestern salamander ambystoma gracile and the spotted salamander ambystoma maculatum were determined in continuous-flow exposures in the laboratory. ninety-six-hour lc50 values were >3.6 mg/l for p. regilla with technical grade guthion and 1.47 mg/l with the formulation guthion 2s (measured as active ... | 1998 | 9601918 |
| effects of ammonium sulfate on growth of larval northwestern salamanders, red-legged and pacific treefrog tadpoles, and juvenile fathead minnows. | | 2000 | 10656895 |
| association of amphibians with attenuation of ultraviolet-b radiation in montane ponds. | ambient ultraviolet-b (uv-b) radiation (280-320 nm) has increased at north-temperate latitudes in the last two decades. uv-b can be detrimental to amphibians, and amphibians have shown declines in some areas during this same period. we documented the distribution of amphibians and salmonids in 42 remote, subalpine and alpine ponds in olympic national park, washington, united states. we inferred relative exposure of amphibian habitats to uv-b by estimating the transmission of 305- and 320-nm radi ... | 2001 | 28547397 |
| effects of agricultural runoff on native amphibians in the lower fraser river valley, british columbia, canada. | hatching success, deformity rates, and survivorship of northern red-legged frogs (rana aurora) and northwestern salamanders (ambystoma gracile) were assessed at three agricultural and three reference sites in the sumas prairie, british columbia, canada. in 1997 and 1998, eggs of both species and eggs of r. aurora, respectively, were placed in nytex mesh cages (irwindale, ca, usa) in roadside ditches at each site. concurrently in 1997, eggs of r. aurora were reared in the laboratory but were expo ... | 2002 | 11833805 |
| organochlorine pesticides and polychlorinated biphenyls (pcbs) in eggs of red-legged frogs (rana aurora) and northwestern salamanders (ambystoma gracile) in an agricultural landscape. | organochlorine pesticides were widely used in the past in sumas prairie, british columbia, canada. in the 1990s, the hatching success of amphibians from agricultural sites was significantly depressed in the sumas prairie compared to reference sites. therefore, in this study, organochlorine pesticides and polychlorinated biphenyls (pcbs) were measured in eggs of red-legged frogs (rana aurora) and northwestern salamanders (ambystoma gracile) from the sumas prairie. egg masses were sampled from thr ... | 2002 | 11999766 |
| effects of nitrate and the pathogenic water mold saprolegnia on survival of amphibian larvae. | we tested for a synergism between nitrate and saprolegnia, a pathogenic water mold, using larvae of 3 amphibian species: ambystoma gracile (northwestern salamander), hyla regilla (pacific treefrog) and rana aurora (red-legged frog). each species was tested separately, using a 3 x 2 fully factorial experiment with 3 nitrate treatments (none, low and high) and 2 saprolegnia treatments (saprolegnia and control). survival of h. regilla was not affected significantly by either experimental factor. in ... | 2006 | 16610589 |
| rangewide landscape genetics of an endemic pacific northwestern salamander. | a species' genetic structure often varies in response to ecological and landscape processes that differ throughout the species' geographic range, yet landscape genetics studies are rarely spatially replicated. the cope's giant salamander (dicamptodon copei) is a neotenic, dispersal-limited amphibian with a restricted geographic range in the pacific northwestern usa. we investigated which landscape factors affect d. copei gene flow in three regions spanning the species' range, which vary in clima ... | 2013 | 23293948 |
| the toxicity of roundup original max to 13 species of larval amphibians. | with the increased use of glyphosate-based herbicides (marketed under several names, including roundup and vision), there has been a concomitant increased concern about the unintended impacts that particular formulations containing the popular surfactant polyethoxylated tallowamine (poea) might have on amphibians. published studies have examined a relatively small number of anuran species (primarily from australia and eastern north america) and, surprisingly, no species of salamanders. using a p ... | 2009 | 19405783 |
| multiple forms of gonadotropin-releasing hormone in amphibian brains. | several forms of gonadotropin-releasing hormone (gnrh)-like molecules were found in brains of both anurans (frogs) and urodeles (salamanders). the presence of the mammalian-like gnrh molecule was confirmed by hplc and cross-reactivity studies. small amounts of salmonid-like gnrh molecules in the brains of frogs (rana pipiens, hyla regilla) and salamanders (taricha granulosa, ambystoma gracile) were detected by comparing the hplc chromatographic pattern and immunological reactivity of the brain e ... | 2012 | 3514371 |
| t4-induced metamorphosis in ambystoma gracile (baird) from two populations: the effects of aging and temperature. | in order to determine the factors affecting the maturation of the functional hypothalamo-pituitary-thyroid axis, ambystoma gracile (baird) larvae of different ages and acclimated to different temperature regimes were exposed to a concentration of thyroxine (t4) which activates the pituitary-thyroid axis. a. gracile from a montane and low-altitude population were utilized. these studies, plus observations concerning spontaneous metamorphosis, indicated that populations of ambystoma gracile are hi ... | 1980 | 7348194 |
| toxicity of the aquatic herbicide, reward®, to the northwestern salamander. | diquat dibromide (db) is the active ingredient in several herbicide products used around the world for industrial and recreational control of terrestrial and aquatic pest plants. this study aimed to assess the adverse effects of the commercial formulation of the aquatic herbicide, reward®, on the pacific northwest amphibian species, the northwestern salamander (ambystoma gracile). larvae were exposed to the reward® herbicide in a 96-h acute bioassay (0.37-151.7 mg/l db) and a continuous 21-day e ... | 2019 | 31456149 |