Literaturdatenbank
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Weller, W. F., Hecnar, S. J., Hecnar, D. R., Casper, G. S., & Dawson, N. F. (2010). Quantitative assessment of intergradation between two subspecies of painted turtles, chrysemys picta bellii and c. p. marginata, in the algoma district of west central ontario, canada. Herpetological Conservation and Biology, 5(2), 166–173.
Added by: Admin (22 Oct 2010 20:35:21 UTC) |
| Resource type: Journal Article BibTeX citation key: Weller2010 View all bibliographic details  |
Categories: General Keywords: Chrysemys, Chrysemys picta, Emydidae, Habitat = habitat, Nordamerika = North America, Schildkröten = turtles + tortoises, Systematik = taxonomy Creators: Casper, Dawson, Hecnar, Hecnar, Weller Collection: Herpetological Conservation and Biology |
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| Abstract |
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Adaptation to local environments after geographical isolation often results in development of distinct physical characteristics in organisms and recognition of subspecies, races or varieties. When barriers are removed secondary contact can result in interbreeding with progeny showing characteristics intermediate between subspecies. Four distinct subspecies of the Painted Turtle, Chrysemys picta, exist and likely resulted from isolation in southern refugia during the last glacial advance. Plastral patterns differ among subspecies of C. picta and turtles from the Algoma District of Ontario, Canada show plastral figure patterns that appear intermediate between the western (C. p. bellii) and midland (C. p. marginata) subspecies. Because former accounts of plastral patterns in painted turtles in this region are largely qualitative, we quantified and compared pattern area, length, width, perimeter/area ratio and geometric shape for Algoma District turtles with known western, midland, and intergrade populations. Plastral patterns in Algoma turtles were very similar to known intergrades from the adjacent Upper Peninsula of Michigan and differed from both western and midland turtles. We found that pattern length and geometric shape, both simple and inexpensive to measure, were useful variables to distinguish intergrades from both western and midland subspecies. Comparisons of measurements from west to east suggest that C. p. bellii characteristics entered into the Algoma District of Ontario from the Upper Peninsula of Michigan during post Pleistocene dispersal. Future genetic analyses may be useful to test our dispersal hypothesis and to determine how far western influence extends eastward into central Ontario.
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