Sexual dimorphism in the radula of Pisania pusio (Linnaeus, 1758) (Mollusca, Gastropoda, Buccinidae)

Abstract

Pisania pusio (Linnaeus, 1758) is an inhabitant of the intertidal zone, being generally found under the rocks during the low tide. It presents spindle, smooth and glossy shell measuring 34 mm of length, with purplish brown color with narrow, revolving, dark brown bands, sometimes in the shape of arrowheads and rachiglossate radula type. The objective of this study was to investigate the occurrence of sexual dimorphism in the size of the radula and in the shape of the teeth among adults of Pisania pusio. Forty-two adult specimens of P. pusio were collected in the Pacheco Beach, Caucaia, State of Ceará, Northeast Brazil. Twenty specimens were males and twenty-two were females. The radula was removed, and then measured with a milimetric slide under compound microscope. Sixty lateral and rachidian teeth of both females and males had five dimensions measured. For comparison of the radula size between sexes, the "t" test of Student was used. For the males the average size of the radula was of 10.25±2.4 mm of length, for the females, the average size of the radula was of 8.87±1.2 mm of length. The length of radular ribbon of showed a statistically significant difference between male and female (p=0.002). The size of the lateral teeth of the males and females showed statistically significant difference in five dimensions measured and the size of the rachidian teeth of males and females showed statistically significant difference in four dimensions measured.