Discordant patterns of evolutionary differentiation in two Neotropical treefrogs.
Comparative studies of codistributed taxa test the degree to which historical processes have shaped contemporary population structure. Discordant patterns of lineage divergence among taxa indicate that species differ in their response to common historical processes. The complex geologic landscape of the Isthmus of Central America provides an ideal setting to test the effects of vicariance and other biogeographic factors on population history. We compared divergence patterns between two codistributed Neotropical frogs (Dendropsophus ebraccatus and Agalychnis callidryas) that exhibit colour pattern polymorphisms among populations, and found significant differences between them in phenotypic and genetic divergence among populations. Colour pattern in D. ebraccatus did not vary with genetic or geographic distance, while colour pattern co-varied with patterns of gene flow in A. callidryas. In addition, we detected significant species differences in the phylogenetic history of populations, gene flow among them, and the extent to which historical diversification and recent gene flow have been restricted by five biogeographic barriers in Costa Rica and Panama. We inferred that alternate microevolutionary processes explain the unique patterns of diversification in each taxon. Our study underscores how differences in selective regimes and species-typical ecological and life-history traits maintain spatial patterns of diversification.
Department of Ecology and Evolutionary Biology, Corson Hall, Cornell University, Ithaca, New York 14853, USA. jmrobertson@uidaho.edu
Jeanne M
JM
Robertson
M Catherine
MC
Duryea
Kelly R
KR
Zamudio
D000818:Animals; D001001:Anura / Q000235:genetics*; D003364:Costa Rica; D004272:DNA, Mitochondrial / Q000235:genetics; D019143:Evolution, Molecular; D051456:Gene Flow; D005819:Genetic Markers; D005828:Genetics, Population; D005843:Geography; D018895:Microsatellite Repeats; D010176:Panama; D010641:Phenotype; D010802:Phylogeny; D010858:Pigmentation / Q000235:genetics; D011110:Polymorphism, Genetic; D017422:Sequence Analysis, DNA; D013045:Species Specificity
D004272:DNA, Mitochondrial; D005819:Genetic Markers