Brachyura, Fiddler crab, Uca, Structural variation, Landmark analysis, Isolation, Ecophenotypy
Journal/Book/Conference Title Title
Isolation due to geographical barriers should promote genetic and morphological divergence among populations. Marine currents flowing in opposing directions along landmasses can constitute barriers that isolate populations dependent upon aquatic dispersal. The distribution of fiddler crabs (genus Uca) is regulated primarily by the oceanic transport of their planktonic larvae and by available adult habitat. Along the Brazilian coast of eastern South America, the flow of 2 major oceanic currents separates northern from southern Uca populations, which may promote intraspecific divergence in ‘trans-Brazilian’ species. Populations of 10 Uca species were sampled at 64 locations north and south of the Ponta do Calcanhar, Rio Grande do Norte, Brazil. Carapace shape was assessed using geometric morphometrics to analyze 12 surface landmarks in 1319 female crabs. Carapace shape differs significantly in each species. In morphospace, the carapace forms of the 10 species appear to separate into traditional subgeneric clusters. Within the 8 species exhibiting trans-Brazilian distributions, northern and southern populations show distinct carapace differences. Depending on species, either the hepatic or the branchial region is larger in northern populations. Since significant genetic variability among such populations has not been confirmed, divergence in carapace shape suggests significant ecological modulation of phenotype within each species. Apparently, environmental differences between northern and southern localities exert a greater impact on carapace morphology than impeded gene flow. The drivers underpinning diversification of carapace shape remain unknown, however.
Department of Biology
Original Publication Date
DOI of published version
UNI ScholarWorks, University of Northern Iowa, Rod Library
© 2014 Kelsey R. Hampton, Melanie J. Hopkins, John C. McNamara, and Carl L. Thurman
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
RIGHTS CHECKING: 4/6/2016 -- Sherpa/Romeo green journal, doja as an open access journal, author can archive publisher's version/pdf, on author's personal website, institutional website and institutional repository, Gold' Open Access = article published by publisher with free availability to all users; available from IR as Open Access (or formerly Free Access). Publisher's PDF may be posted on the Author's personal or institutional website or deposited into the Author's institutional Open Access repository any time after publication only if the article is published with 'Gold' Open Access. In all cases, the article on a website or in the repository must have a link to its abstract page on the Inter-Research website, and cite the article doi.