rugae), rat (8) and golden hamster (7). We showed that palatal growth rate, spacing and addition rate in mouse/rat were remarkably similar (with respect to the embryo size difference), and that increase to 9 rugae in mouse is achieved by postponing the end of the addition process (hypermorphosis). Such a heterochronic shift may be typical of 1 variations observed among muroid rodents. In contra...

Although the cichlid fishes from Lake Tanganyika are treated as a textbook example of adaptive radiation, many taxonomic problems remain unresolved. Cyathopharynx furcifer, which belongs to the currently monospecific genus Cyathopharynx, contains two colour morphs at the southern end of the lake: one has a yellow anal fin, and the other has a black anal fin. Some books for hobbyists of ornament...

INTRODUCTlON ,. . The foundation of most evolutionary theory rests upon inferences drawn from geographic variation or upon the verification of predictions made about it. The study of geographic variation occupies a central position in evolutionary biology. .. because geographic variation is ordinarily the smallest amount of evolution that can be detected in nature and because evolutionary theor...

Three new species of the genus Herichthys are described on the basis of chromatic, morphometric, and meristic characters. Herichthys pratinus sp. nov. from the Rio Salto in San Luis Potosi is characterized by a steep and shallow predorsal profile, a concavity before the eye, and adult males with a prominent forehead forming a nuchal hump, DXV-XVI, 10-11; and AV, 8-9. Herichthys pame sp. nov. fr...