Asymmetry of eye peduncle length in Euprotomus iredalei (Abbott, 1960) (Mollusca: Neostromboidae: Strombidae)

Abstract Objective The objective of this study was to determine the length of each eye peduncle of Euprotomus iredalei from Karratha, Western Australia. This study seeks to test the hypothesis that the difference in right and left eye peduncle length is a natural phenomenon and not an aberration caused by imposex, as alluded to in the literature. Results In the material examined (n = 39) there was no evidence of imposex and all animals had eye peduncles that were of different lengths. This length difference was significant ( t (38) = 10.315, p < 0.001) in the length of the eyestalks with the right peduncle longer (8.86 mm ± 0.23 SE) than the left (7.32 mm ± 0.19), and the effect size was large ( d = 1.05). There was no sexual dimorphism in the difference in proportional length of the eye peduncles between males and females ( t (38) = 0.056, p = 0.955).