Cephalofoil dimorphism
Stingray mating



Stingray mating

Female stingray showing numerous fresh mating wounds along the posterior margin of the body disc.

Dentition from a male stingray in the mating season (top) and the non-mating seaons (middle) and a female stingray (bottom).

Male elasmobranchs bite and grip the body of their female mates during courtship and copulation. In batoids (skates & rays), this gripping action is facilitated by the development of sharp, cuspidate dentition on the males only. Female dentition is generally molariform but, despite the differences in tooth morphology, the diets of the sexes remain the same.

Although the phenomenon of dental sexual dimorphism has been previously documented, it was only recently discovered that male dentition changes shape on a seasonal basis. Only during the mating season does the male dentition develop the cuspidate tooth morphology; during the non-mating season the male dentition is molariform, similar in shape to the female dentition which does not change seasonally.

In conjunction with studies of the tooth morphology, the resultant mating wounds on female rays were quantified. Females have a dermis that is 50% thicker than comparably sized males, presumably to provide protection from the vigorous mating bites of the males. The majority of bite wounds are located on the posterior half of the body disc of the females. Some males also possess bite wounds but they are much less common compared to the females. The mating wounds closely follow the seasonal appearance of the cuspidate male dentition.

Kajiura, SM, AP Sebastian & TC Tricas. 2000. Dermal bite wounds as indicators of reproductive seasonality and behaviour in the Atlantic stingray, Dasyatis sabina. Environmental Biology of Fishes 58(1): 23-31.

Kajiura, SM & TC Tricas. 1996. Seasonal dynamics of dental sexual dimorphism in the Atlantic stingray, Dasyatis sabina. Journal of Experimental Biology 199(10): 2297-9306.

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modified Dec 30 2003