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Evolution in a Paedomorphic Lineage. I. An Electrophoretic Analysis of the Mexican Ambystomatid Salamanders
H. Bradley Shaffer
Vol. 38, No. 6 (Nov., 1984), pp. 1194-1206
Published by: Society for the Study of Evolution
Stable URL: http://www.jstor.org/stable/2408628
Page Count: 13
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The Mexican ambystomatid radiation is relatively young, originating about 10-12 million years BP. Within the group, phylogenetic relationships primarily reflect the geology of the Mexican plateau. Mountain forms split off from plateau species coincident with the uplift of the Neovolcanic Axis, which is postulated as having caused the initial separation of the group. The plateau species form 3 groups whose distribution corresponds with the drainage patterns of the Mesa Central. Larval reproduction has evolved independently several times in the Mexican ambystomatids and appears to be an evolutionarily labile character. Genetic divergence between non-transforming salamander populations is greater than that between metamorphosing ones, presumably due to restricted gene flow between isolated, non-transforming populations. Thus, the fixation of larval reproduction itself may be an important factor in the speciation process in these salamanders.
Evolution © 1984 Society for the Study of Evolution