VARIATION IN CRANIAL FORM AND SEXUAL DIMORPHISM AMONG 5 EUROPEAN POPULATIONS OF THE OTTER LUTRA-LUTRA

Craniometric variation between otters Lutra lutra (L.) from Ireland, S cotland, Shetland, Norway, and Czechoslovakia was examined using multi variate statistical analyses. Significant sexual dimorphism in cranial size and shape occurred in all samples, although the degree of dimorp hism varied between samples, with the Irish sample exhibiting the most . Morphological differences were also observed across samples. Three g roups were observed; Irish, Scottish, (Mainland and Shetland), and Mai nland European, though within the two composite groups the samples wer e still differentiable. There was a good agreement between the pattern s of variation between male and female samples, but morphological diff erentiation was not significantly correlated with geographic separatio n. These results are discussed in the light of our current knowledge o f the ecology of the species in Europe. It is argued that, while there is morphological evidence for subspecific status of the Irish otter ( as L. l. roensis), further investigations of morphological and genetic variation across Eurasia are clearly required.