PATTERNS OF VARIATION IN CRANIAL SIZE AND SHAPE IN 2 COEXISTING GERBILLINE RODENTS

Patterns of cranial variation within and between two coexisting gerbil line rodents from the Namib Desert were assessed. Size of individual c ranial characters is more variable in Desmodillus auricularis than in Gerbillurus paeba, but G. paeba is more variable in aspects of morphol ogical shape. This contrasting pattern of variability in size and in s hape has implications for ecomorphological studies. Without informatio n on the relative functional importance of these two aspects of morpho logy, there appears to be little basis for using data on morphological variation to derive ecological generalizations. It is suggested that the strikingly different degree of correlation among cranial measureme nts in these two species is related to differences in growth rates and demographic seasonality.