Life history and morphology of the hippolytid shrimp Hippolyte ventricosa in Kominato bay [Japan].

Abstract

The life history and morphological characteristics of a hippolytid shrimp Hippolyte ventricosa were investigated during 1983 and 1984 in Kominato Bay, Chiba prefecture. The two or more generations in the year could be observed according to the distributions of carapace length and number of eggs carried. Two rostrum types were observed; Sword type and Blade type. In the Sword type, the lower border of rostrum was straight from base to distal edge, while in the Blade type, it was expanded roundly. The number of lower border teeth of rostrum was significantly different between two types. 99% of the male was Sword type. In the female, the proportion of the Blade type reached only 78%. The ovigerous ratio of the Blade type was higher than that of the Sword type. These results indicate the sexual dimorphism of Hipplyte ventricosa.