A STUDY OF ALTITUDINAL RACES IN RANA PIPIENS

摘要: Of all the Mexican Amphibia only one species, Rana pipiens, is found in biotic zones of Mexico. It inhabits high mountains, deserts, and tropical lowlands. The general factor that limits its distribution absence sufficient water. overall range pipiens from north central Canada to Panama, consequently unique within Mexico but a reflection adaptability species over entire range. work Moore (1946, 1947 1949) has demonstrated local populations Canada, eastern United States, lowland differ each other with respect number embryonic features. differences between were be correlated environmental temperatures thus direct adaptive significance. was further shown when frogs different localities are crossed there an increase hybrid abnormalities as north-south distance parental increases. Later by (1950) male mountains Costa Rica, females northeastern States produced very slight abnormalities. This unexpected result inasmuch these two greater than any cross. Since Rica available for experiments no embryological data obtained. reported here study studied highlands Central Plateau, tropics, intermediate altitudes. purpose this determine some features characterize populations, their genetic structure means crossing States. By use methods aspects adaptations various altitudes may ascertained, picture differentiation population gene flow also provided. analogy it believed on would provide insight into paradoxical results obtained Rican frogs. Furthermore, hoped type evidence concerning historical zoogeography pipiens.