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  • 1
    Digitale Medien
    Digitale Medien
    Populational Changes of the Enteric Protozoans Opalina spp. and Nyctotherus cordiformis During the Ontogeny of Anuran Tadpoles (1990)
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 37 (1990), S. 0 
    Details
    ISSN: 1550-7408
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: . We studied ontogenetic population changes of Opalina and Nyctotherus cordiformis in eight species of tadpoles from 10 sites in east-central Mississippi. Most tadpoles acquired Opalina early in development, while the acquisition of N. cordiformis was variable. Developmental stage, species and collection site explained significant amounts of the variation in Opalina density of tadpoles (F= 11.6; df = 27, 235; P 〈 0.0001) and metamorphs (F= 7.31; df = 24, 84; P 〈 0.0001). Relationships between Opalina density and host stage showed either (1) a gradual decrease or (2) a gradual increase throughout host ontogeny. Opalina densities declined during metamorphosis. Density variations of N. cordiformis were explained by host species of tadpoles (F= 9.30; df = 7, 142; P 〈 0.0001) and by host species and stage of metamorphs (F= 5.85; df = 8, 62; P 〈 0.0001).The length of larval period, habitat duration and generation time of the protozoans are suggested as major modifiers of the protozoan densities. Hosts with long larval periods show a decreasing population density and hosts with short developmental periods show a pattern of increasing density. Neither pattern was detected in tadpoles from temporary sites. Metamorphic declines in protozoan density, but not necessarily the loss of protozoans, reflect metamorphic alterations of the gut common to all hosts.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1550-7408.1990.tb01251.x
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  • 2
    Digitale Medien
    Digitale Medien
    Physical, chemical and biological dynamics of five temporary dystrophic forest pools in Central Mississippi (1997)
    Springer
    Hydrobiologia 353 (1997), S. 77-89 
    Details
    ISSN: 1573-5117
    Schlagwort(e): freshwater temporary pools ; ephemeral water ; amphibianbreeding habitats; invertebrate fauna
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Five temporary forest pools at Noxubee National WildlifeRefuge,Noxubee Co., Mississippi were surveyed monthly for three yearstogain a better understanding of the dynamics of temporaryaquatichabitats. The objective of this study was to characterize thephysicochemical and biological changes in temporary pools inorderto assess the temporal habitat diversity. These ecosystems,allwithin no more than 4 km of one another, were heterotrophicwith adetrital-based food web derived from allochthonous leaflitter.These pools were chosen because of their close proximity tooneanother, they historically filled and dried seasonally, andtheywere known breeding sites for resident amphibian populations.Only47% of the amphibian cohorts inhabiting the pools appeared tothrive and metamorphose prior to pool desiccation. Successfuldevelopment and dispersal of larvae was variable among poolsandyears. We found that the filling cycles differed amonghabitats andthat physiochemical and biological parameters were highlyvariable.Our data suggest that ephemeral pools in this central piedmontregion of Mississippi are each unique and represent habitatsof lowpredictability for amphibian breeding and success. We concludethatit is erroneous to draw generalizations regarding a ‘typical’temporary pool ecosystem within this region.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003098526340
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  • 3
    Digitale Medien
    Digitale Medien
    Sequence of ontogenetic development and atrophy of the oral apparatus of six anuran tadpoles (1988)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 197 (1988), S. 63-69 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The development of the oral structures of six species of anuran tadpoles with four different types of mouth parts and the metamorphic atrophy of these structures in two species with different mouth parts are described. The oral labia of typical tadpoles, oral flaps of microhylids, and lateral oral folds of Rhinophrynus are assumed to be homologous. We also suggest that the barbels of the tadpoles of Rhinophrynus are homologs of the marginal papillae of species with an oral disc. Developmental patterns and sequences of the oral structures of all tadpoles examined follow a common pattern: stomodeal invagination, oral pad development, jaw sheeth delimitation, tooth row ridge development, jaw sheath keratinization, and labial tooth keratinization. Developmental patterns remain constant, while interspecific differences are apparent because of truncations of ontogeny at specific stages. Metamorphic atrophy of oral structures occurs roughly in the reverse order of development, although the procedure is rapid and more haphazard than development.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051970106
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  • 4
    Digitale Medien
    Digitale Medien
    Oral disc muscles of anuran tadpoles (1991)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 208 (1991), S. 271-277 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The presence and configurations of the small, extrinsic muscle fibers of the M. mandibulolabialis superior in the upper labium and the M. inferior in the lower labium are described for 24 species in 9 families. Although several species possess only the M. inferior, or both the M. inferior and superior, none has only the M. superior. Some species without tooth rows possess the M. inferior, and microhylid tadpoles have a single-stranded muscle different than the M. mandibulolabialis in each oral flap. The extrinsic oral muscles insert near the bottom of the inter-row valleys behind each tooth ridge and the bases of marginal papillae lateral to the ends of tooth rows. Muscles do not extend to marginal papillae beyond the most distal row of teeth. Muscle contraction is presumed to rotate the teeth distally so that they contact the substrate at the proper working angle. This action probably occurs at full extension of the oral disc just before disc closure starts.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1052080304
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  • 5
    Digitale Medien
    Digitale Medien
    Configurations of the rectus abdominis muscle of anuran tadpoles (1992)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 214 (1992), S. 351-356 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Configurations of the rectus abdominis in tadpoles of 60 anuran species in 13 families were examined. This muscle is present by Gosner stage 25 and does not change until late in metamorphosis. The anterior terminus of the r. abdominis usually is a straight, transverse front or fan-shaped array only loosely associated with the rectus cervicis. In some suspension feeders (Rhinophrynus, Xenopus, but not microhylids), macrophagous suction feeders (Lepidobatrachus) and bromeliad inhabitants (Hyla bromeliacia) the r. abdominis is contigous with the r. cervicis which continues anterolaterally and dorsally from the wall of the spiracular cavity. Suctorial forms (Scutiger), those that live in confined spaces (burrowers, Centrolenella; bromeliad inhabitants, Hyla bromeliacia), and the taxa that have the r. cervicis and r. abdominis contiguous all have closed myosepta; the myosepta of other taxa; except for ones with large tadpoles (e.g., Rana catesbeiana), have large gaps between at least anterior myotomes. These initial data suggest that the configurations of the r. abdominis have responded to selection based on ecomorphological function and convergence among lineages are noted. © 1992 Wiley-Liss, Inc.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1052140310
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