W. Crampton | University of Central Florida (original) (raw)
Papers by W. Crampton
Journal of Experimental Biology, 2013
Summary A complete understanding of animal signal evolution necessitates analyses of both the pro... more Summary A complete understanding of animal signal evolution necessitates analyses of both the proximate (e.g. anatomical and physiological) mechanisms of signal generation and reception, and the ultimate (i.e. evolutionary) mechanisms underlying adaptation and diversification. Here we summarize the results of a synthetic study of electric diversity in the species-rich neotropical electric fish genus Gymnotus. Our study integrates two research directions. The first examines the proximate causes of diversity in the electric organ discharge (EOD) – which is the carrier of both the communication and electrolocation signal of electric fishes – via descriptions of the intrinsic properties of electrocytes, electrocyte innervation, electric organ anatomy and the neural coordination of the discharge (among other parameters). The second seeks to understand the ultimate causes of signal diversity – via a continent-wide survey of species diversity, species-level phylogenetic reconstructions and...
Journal of Experimental Biology, 2013
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Journal of Fish Biology, 2008
Matched sets of gillnets of different mesh-sizes were used to evaluate the degree to which contig... more Matched sets of gillnets of different mesh-sizes were used to evaluate the degree to which contiguous and connected flooded forest and floating meadow habitats are characterized by distinct fish faunas during the flooding season in the Peruvian Amazon. For fishes between 38-740 mm standard length (L S ) (the size range captured by the gear), an overriding pattern of faunal similarity emerged between these two habitats. The mean species richness, diversity, abundance, fish mass, mean and maximum L S , and maximum mass did not differ significantly between flooded forest and floating meadows. Species abundances followed a log-normal distribution in which three species accounted for 60-70% of the total abundance in each habitat. Despite these similarities, multivariate analyses demonstrated subtle differences in species composition between flooded forest and adjacent floating macrophytes. In addition, the absolute number of species was higher in flooded forest, reflecting a higher percentage of rare species. The day-night species turnover was found to be greater in flooded forests than floating meadows. Further, nocturnal samples had higher abundances and greater species richness than diurnal samples in both habitats. Differences in habitat structural complexity between flooded forest and floating meadows may result in a higher abundance and species richness of day-active species in floating meadows.
Journal of Fish Biology, 1998
This paper explores the relationship between dissolved oxygen concentration and the distribution ... more This paper explores the relationship between dissolved oxygen concentration and the distribution and electric signal diversity of 64 species of gymnotiforms from the Tefé region of the upper Amazon basin. Seventeen species are able to tolerate protracted periods of anoxia in inundated várzea floodplains or in terra firme swamps. The majority do so by breathing air-either with specialist accessory air-breathing organs or via their gills. An assemblage of 38 species of gymnotiforms which are unable to tolerate hypoxia undertake lateral migrations from well-oxygenated river channels into and out of the várzea floodplain in response to oxygen availability. These have evolved behavioural adaptations to avoid hypoxic water. While there is a mix of tone-and pulse-type electric organ discharges (EODs) in species that live only in permanently well-oxygenated habitats, 16 out of the 17 species that live in anoxic habitats have pulse-type EODs. The tone-type signals may have less flexible and perhaps greater overall energetic demands that impose handicaps in habitats where oxygen is a limiting factor. Many tone-type species also have more active swimming behaviour which could impose further energetic demands. 1998 The Fisheries Society of the British Isles
Journal of Fish Biology, 1996
Estimates of the density, biomass and species diversity of fish from floating meadow and flooded ... more Estimates of the density, biomass and species diversity of fish from floating meadow and flooded forest habitats suggest that gymnotiform fish constitute an important component of Amazonian flood plain fish faunas. Electric eels, Electrophorus electricus are unexpectedly abundant within várzea forest. 1996 The Fisheries Society of the British Isles
Neotropical Ichthyology, 2008
Systematics and Biodiversity, 2005
Science, 1996
unpublished results. 60. In cases where partners were marked with the same genetic marker (most o... more unpublished results. 60. In cases where partners were marked with the same genetic marker (most of ), disomic animals could not be positively identified in the F1 generation. Therefore, in each experiment a large number (30) of randomly selected ry+ or y+ F1 progeny (which includes both 1 Dp and 2 Dp animals) were outcrossed to XAY, y/O; ry506 males. The 2 Dp F1 animals used to estimate disjunction frequencies were identified by observation of high transmission rates in the F2 scoring generation. Nondisjunction rates were calculated as above, except that the nondisjunction class was determined by doubling the number of 0 Dp animals in the F2 generation. This correction was necessary because the 2 Dp nondisjunction progeny could not be distinguished phenotypically from the 1 Dp class in these crosses. The fact that recovery of the 0 Dp and 2 Dp classes did not differ significantly when both classes could be monitored independently strongly validates the use of this correction. Furthermore, outcrossing the F2 ry+ progeny from putative y1230/y1230 F1 animals demonstrated that the F2 progeny contained equal numbers of 0 Dp and 2 Dp animals (G. H. Karpen et al., data not shown). This result confirmed both the disomic nature of the Fl parents and the appropriateness of using the 0 Dp class to estimate nondisjunction. 61. Animals with two differentially marked minichromosomes and zero, one, or two copies of the P(nod+) transgene were generated from the cross y; P(nod+)/SM1, Cy; ry; 31E, y+ females xy/Y; P(nod+)/ Sp; ry; J21A, ry+ males (or 20A or lOB). The y; P(nod+)/Sp; ry female progeny provided the 2E+1T class, and the 2E+2T females were the y; P(nodl)/ P(nod+); ry siblings. The J21A monosome siblings (y-ry+) were used for the transmission tests, whereas the 31E/J21A, 31E/1OB, and 31E/20A disomes (y+ ry+) were used in the nondisjunction tests. The 2E+OT control ND frequencies were taken from the data in , because independent analyses demonstrated that the SM1 balancer raises nondisjunction frequencies significantly. For the J21A monosome transmission tests, the 2E+OT class used in the transmission assay were produced by the cross y; ry; J21A, ry+ females x y/Y; P(nod+)/ Sp; ry males. All test females were crossed and the results analyzed as described (56, 57). 62. T. Murphy contributed significantly to discussions and data analyses, and his efforts are gratefully acknowledged. We also thank K
Journal of Fish Biology, 2012
Gymnotus capanema n. sp. is described on the basis of cytogenetic, morphometric, meristic and ost... more Gymnotus capanema n. sp. is described on the basis of cytogenetic, morphometric, meristic and osteological data from nine specimens (one male and eight females) from the municipality of Capanema, Pará, in the eastern Amazon of Brazil. Later, three additional specimens were found in museums and regarded as nontypes (not cytogenetically analysed). Gymnotus capanema, which occurs in sympatry with Gymnotus cf. carapo cytotype 2n = 42 (30m/sm + 12st/a) exhibits a novel karyotype for the genus, with 2n = 34 (20m/sm + 14st/a). Gymnotus capanema can be unambiguously diagnosed from all congeners on the basis of a combination of characters from external anatomy, pigmentation and osteology. The constitutive heterochromatin, rich in adenine-thymine (A-T) base pairs [4',6 diamidino-2-phenylindole dihydrochloride (DAPI) positive], occurs in the centromeric region of all of the chromosomes, and in the pericentromeric and the entire short arm of some chromosomes. The nucleolar organizing region (NOR), stained by silver nitrate, chromomycin A(3) (CMA(3)) and 18S ribosomal (r)DNA fluorescence in situ hybridization (FISH), occurs in the short arm of pair 15. FISH, with telomeric probes did not show interstitial telomeric sequences (ITS), despite the reduced 2n in comparison to the karyotypes of other species of Gymnotus. The karyotype of G. capanema, with a reduced 2n, is strikingly different from all other previously studied congeners.
Journal of Experimental Biology, 2013
Summary A complete understanding of animal signal evolution necessitates analyses of both the pro... more Summary A complete understanding of animal signal evolution necessitates analyses of both the proximate (e.g. anatomical and physiological) mechanisms of signal generation and reception, and the ultimate (i.e. evolutionary) mechanisms underlying adaptation and diversification. Here we summarize the results of a synthetic study of electric diversity in the species-rich neotropical electric fish genus Gymnotus. Our study integrates two research directions. The first examines the proximate causes of diversity in the electric organ discharge (EOD) – which is the carrier of both the communication and electrolocation signal of electric fishes – via descriptions of the intrinsic properties of electrocytes, electrocyte innervation, electric organ anatomy and the neural coordination of the discharge (among other parameters). The second seeks to understand the ultimate causes of signal diversity – via a continent-wide survey of species diversity, species-level phylogenetic reconstructions and...
Journal of Experimental Biology, 2013
The user has requested enhancement of the downloaded file.
Journal of Fish Biology, 2008
Matched sets of gillnets of different mesh-sizes were used to evaluate the degree to which contig... more Matched sets of gillnets of different mesh-sizes were used to evaluate the degree to which contiguous and connected flooded forest and floating meadow habitats are characterized by distinct fish faunas during the flooding season in the Peruvian Amazon. For fishes between 38-740 mm standard length (L S ) (the size range captured by the gear), an overriding pattern of faunal similarity emerged between these two habitats. The mean species richness, diversity, abundance, fish mass, mean and maximum L S , and maximum mass did not differ significantly between flooded forest and floating meadows. Species abundances followed a log-normal distribution in which three species accounted for 60-70% of the total abundance in each habitat. Despite these similarities, multivariate analyses demonstrated subtle differences in species composition between flooded forest and adjacent floating macrophytes. In addition, the absolute number of species was higher in flooded forest, reflecting a higher percentage of rare species. The day-night species turnover was found to be greater in flooded forests than floating meadows. Further, nocturnal samples had higher abundances and greater species richness than diurnal samples in both habitats. Differences in habitat structural complexity between flooded forest and floating meadows may result in a higher abundance and species richness of day-active species in floating meadows.
Journal of Fish Biology, 1998
This paper explores the relationship between dissolved oxygen concentration and the distribution ... more This paper explores the relationship between dissolved oxygen concentration and the distribution and electric signal diversity of 64 species of gymnotiforms from the Tefé region of the upper Amazon basin. Seventeen species are able to tolerate protracted periods of anoxia in inundated várzea floodplains or in terra firme swamps. The majority do so by breathing air-either with specialist accessory air-breathing organs or via their gills. An assemblage of 38 species of gymnotiforms which are unable to tolerate hypoxia undertake lateral migrations from well-oxygenated river channels into and out of the várzea floodplain in response to oxygen availability. These have evolved behavioural adaptations to avoid hypoxic water. While there is a mix of tone-and pulse-type electric organ discharges (EODs) in species that live only in permanently well-oxygenated habitats, 16 out of the 17 species that live in anoxic habitats have pulse-type EODs. The tone-type signals may have less flexible and perhaps greater overall energetic demands that impose handicaps in habitats where oxygen is a limiting factor. Many tone-type species also have more active swimming behaviour which could impose further energetic demands. 1998 The Fisheries Society of the British Isles
Journal of Fish Biology, 1996
Estimates of the density, biomass and species diversity of fish from floating meadow and flooded ... more Estimates of the density, biomass and species diversity of fish from floating meadow and flooded forest habitats suggest that gymnotiform fish constitute an important component of Amazonian flood plain fish faunas. Electric eels, Electrophorus electricus are unexpectedly abundant within várzea forest. 1996 The Fisheries Society of the British Isles
Neotropical Ichthyology, 2008
Systematics and Biodiversity, 2005
Science, 1996
unpublished results. 60. In cases where partners were marked with the same genetic marker (most o... more unpublished results. 60. In cases where partners were marked with the same genetic marker (most of ), disomic animals could not be positively identified in the F1 generation. Therefore, in each experiment a large number (30) of randomly selected ry+ or y+ F1 progeny (which includes both 1 Dp and 2 Dp animals) were outcrossed to XAY, y/O; ry506 males. The 2 Dp F1 animals used to estimate disjunction frequencies were identified by observation of high transmission rates in the F2 scoring generation. Nondisjunction rates were calculated as above, except that the nondisjunction class was determined by doubling the number of 0 Dp animals in the F2 generation. This correction was necessary because the 2 Dp nondisjunction progeny could not be distinguished phenotypically from the 1 Dp class in these crosses. The fact that recovery of the 0 Dp and 2 Dp classes did not differ significantly when both classes could be monitored independently strongly validates the use of this correction. Furthermore, outcrossing the F2 ry+ progeny from putative y1230/y1230 F1 animals demonstrated that the F2 progeny contained equal numbers of 0 Dp and 2 Dp animals (G. H. Karpen et al., data not shown). This result confirmed both the disomic nature of the Fl parents and the appropriateness of using the 0 Dp class to estimate nondisjunction. 61. Animals with two differentially marked minichromosomes and zero, one, or two copies of the P(nod+) transgene were generated from the cross y; P(nod+)/SM1, Cy; ry; 31E, y+ females xy/Y; P(nod+)/ Sp; ry; J21A, ry+ males (or 20A or lOB). The y; P(nod+)/Sp; ry female progeny provided the 2E+1T class, and the 2E+2T females were the y; P(nodl)/ P(nod+); ry siblings. The J21A monosome siblings (y-ry+) were used for the transmission tests, whereas the 31E/J21A, 31E/1OB, and 31E/20A disomes (y+ ry+) were used in the nondisjunction tests. The 2E+OT control ND frequencies were taken from the data in , because independent analyses demonstrated that the SM1 balancer raises nondisjunction frequencies significantly. For the J21A monosome transmission tests, the 2E+OT class used in the transmission assay were produced by the cross y; ry; J21A, ry+ females x y/Y; P(nod+)/ Sp; ry males. All test females were crossed and the results analyzed as described (56, 57). 62. T. Murphy contributed significantly to discussions and data analyses, and his efforts are gratefully acknowledged. We also thank K
Journal of Fish Biology, 2012
Gymnotus capanema n. sp. is described on the basis of cytogenetic, morphometric, meristic and ost... more Gymnotus capanema n. sp. is described on the basis of cytogenetic, morphometric, meristic and osteological data from nine specimens (one male and eight females) from the municipality of Capanema, Pará, in the eastern Amazon of Brazil. Later, three additional specimens were found in museums and regarded as nontypes (not cytogenetically analysed). Gymnotus capanema, which occurs in sympatry with Gymnotus cf. carapo cytotype 2n = 42 (30m/sm + 12st/a) exhibits a novel karyotype for the genus, with 2n = 34 (20m/sm + 14st/a). Gymnotus capanema can be unambiguously diagnosed from all congeners on the basis of a combination of characters from external anatomy, pigmentation and osteology. The constitutive heterochromatin, rich in adenine-thymine (A-T) base pairs [4',6 diamidino-2-phenylindole dihydrochloride (DAPI) positive], occurs in the centromeric region of all of the chromosomes, and in the pericentromeric and the entire short arm of some chromosomes. The nucleolar organizing region (NOR), stained by silver nitrate, chromomycin A(3) (CMA(3)) and 18S ribosomal (r)DNA fluorescence in situ hybridization (FISH), occurs in the short arm of pair 15. FISH, with telomeric probes did not show interstitial telomeric sequences (ITS), despite the reduced 2n in comparison to the karyotypes of other species of Gymnotus. The karyotype of G. capanema, with a reduced 2n, is strikingly different from all other previously studied congeners.