Intra-specific variation in Pelophylax ridibunda (Rana ridibunda) in Southern Iran: life history and developmental patterns

This study describes the influences of variations in life history traits and developmentalpatterns of pelophylax ridibunda. the causes of this variation were investigated bycomparing observed patterns of inter-populational differences from geographic variables.the aim of the study was to investigate whether embryos and larvae from differentpopulations of p. ridibunda show the same pattern of development when they are rearedin the same conditions in the laboratory and to find out further whether if any differencesappearing in the pattern among populations is environmentally or genetically based. eggmasses of p. ridibunda were collected from four sites in fars province, iran and reared inthe same conditions. samples from most of the developmental stages were fixed andclutch parameters were measured at early developmental stages. morphological charactersin embryos and larvae including egg diameter, growing size of embryos and larvae atdifferent stages, external gill, cement gland and mouth parts structures were examinedwith light and scanning electron microscopy. statistical analysis showed that the meandiameter of eggs and jelly coats were significantly different (p < 0.05) from each other inall four populations. in addition, variation among sites in developmental stage at time ofembryos and larvae were found. the results also showed at least three different types ofdental formula, two main branches of external gill on each side, and type a cement glanddevelopmental pattern among the populations. our data suggest that local adaptationmay be responsible for life history, and morphometric and morphological variationsamong eggs, embryos and larvae of p. ridibunda. further study is needed to quantify therelative contributions of the genotype and the environment to embryo and tadpolemorphology and to assess the adaptive significance of morphological differences.