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Field Investigations Of Malformed Frogs In Minnesota 1993-97, Judy C. Helgen, Mark C. Gernes, Susan M. Kersten, Joel W. Chirhart, Jeff T. Canfield, Dorothy Bowers, Jon Haferman, Robert G. Mckinnell, David M. Hoppe
Field Investigations Of Malformed Frogs In Minnesota 1993-97, Judy C. Helgen, Mark C. Gernes, Susan M. Kersten, Joel W. Chirhart, Jeff T. Canfield, Dorothy Bowers, Jon Haferman, Robert G. Mckinnell, David M. Hoppe
Journal of the Iowa Academy of Science: JIAS
Reports of malformed frogs were made to the Minnesota Pollution Control Agency (MPCA) from different parts of Minnesota in 1993, 1995, 1996, and 1997 and one, nine, 190, and 172 reports were received, respectively. MPCA field crews and Drs. Hoppe and McKinnell documented malformed frog locations starting in 1993. By 1997, MPCA field crews documented malformed frogs at 62 locations in Minnesota, in 29 of 87 counties. Most malformations were in young metamorphs of Rana pipiens but they were observed also in R. clamitans, R. septentrionalis, R. sylvatica, Bufo americanus, and Hyla spp. Frequencies of malformations varied by time of …
History Of Minnesota Frog Abnormalities: Do Recent Findings Represent A New Phenomenon?, David M. Hoppe
History Of Minnesota Frog Abnormalities: Do Recent Findings Represent A New Phenomenon?, David M. Hoppe
Journal of the Iowa Academy of Science: JIAS
Two lines of investigation were used to determine whether recent Minnesota reports of frog abnormalities differ from historical reports: (1) museum collection studies paired with follow-up field surveys, and (2) comparison of recent and earlier field surveys in west-central Minnesota. For the museum study I examined 2433 northern leopard frogs (Rana pipiens) in the Bell Museum of Natural History collections of the University of Minnesota, collected during 1958-63. 0.7% of frogs were found to have abnormalities, consisting of 0.5% predator amputations and 0.2% malformations. Three types of malformation were found: missing hindlimbs, vestigial feet, and fused digits. Conspicuously absent from …
Reduction In Road Mortality In A Northern Leopard Frog Population, Madeleine H. Linck
Reduction In Road Mortality In A Northern Leopard Frog Population, Madeleine H. Linck
Journal of the Iowa Academy of Science: JIAS
Since spring of 1994, Hennepin Parks Natural Resources Management staff, assisted by numerous volunteers, has been working to reduce road mortality among migrating Northern Leopard Frogs (Rana pipiens) adjacent to Baker Park Reserve in Maple Plain, Hennepin County, Minnesota. A county road separates the overwintering site from breeding habitat within the park. With steadily increasing traffic over the years, this population of frogs was in serious decline. For the first two years (1994 and 1995) rescue efforts were limited to the spring collection of frogs as they migrated out of the overwintering lake coward the breeding wetlands, although the road …
Defining Anuran Malformations In The Context Of A Developmental Problem, Carol U. Meteyer, Rebecca A. Cole, Kathryn A. Converse, Douglas E. Docherty, Mark Wolcott, Judy C. Helgen, Richard Levey, Laura Eaton-Poole, James G. Burkhart
Defining Anuran Malformations In The Context Of A Developmental Problem, Carol U. Meteyer, Rebecca A. Cole, Kathryn A. Converse, Douglas E. Docherty, Mark Wolcott, Judy C. Helgen, Richard Levey, Laura Eaton-Poole, James G. Burkhart
Journal of the Iowa Academy of Science: JIAS
This paper summarizes terminology and general concepts involved in animal development for the purpose of providing background for the study and understanding of frog malformations. The results of our radiographic investigation of rear limb malformations in Rana pipiens provide evidence that frog malformations are the product of early developmental errors. Although bacteria, parasites and viruses were identified in these metamorphosed frogs, the relevant window to look for the teratogenic affect of these agents is in the early tadpole stage during limb development. As a result, our microbiological findings must be regarded as inconclusive relative to determining their contribution to malformations …