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Ontogenetic color change in the crayfish Cambarus b. bartonii and Faxonius obscurus: a test of Ortmann's hypotheses
Hartzell SM 
Published Online: 12/31/2017
Abstract
In crayfish, intraspecific coloration can vary due to a variety of factors such as diet, genetic variation, environment, and ontogeny. Ortmann (1906) hypothesized that the crayfish Cambarus bartonii bartonii and Faxonius obscurus exhibit an ontogenetic shift in color change, with greener coloration in younger individuals of both species diminishing with age in larger specimens. However, this hypothesis has never been quantitatively tested. This work incorporated digital image analysis to quantify coloration of samples of C. b. bartonii and F. obscurus collected from two locations, respectively, in an eastern Pennsylvania stream. Examination for relationships between coloration (percent “green dominanceâ€, i.e., the proportion of green in comparison to blue and red in photographs) and body size did not reveal any significant relationship between these variables in either crayfish species. Therefore, this study does not support the presence of ontogenetic color change in C. b. bartonii and F. obscurus, and suggests intraspecific variation of color in both species may be primarily influenced by other factors.
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How to Cite
Hartzell SM. (2017). Ontogenetic color change in the crayfish Cambarus b bartonii and Faxonius obscurus: a test of Ortmann's hypotheses. Freshwater Crayfish 23(1):59-63. doi: 10.5869/fc.2017.v23-1.59
Author Information
Sean M. Hartzell,* Department of Biological and Allied Health Sciences, Bloomsburg University of Pennsylvania, 260 Edgar Avenue, Bloomsburg, PA, United States17815. E-mail: seanhartzell77@gmail.com
Corresponding Author indicated by an *.
Publication History
Manuscript Submitted: 12/1/2017
Manuscript Accepted: 12/22/2017
Published Online: 12/31/2017
Published in Print: 12/31/2017
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