HISTOLOGY OF A BILATERAL GYNANDROMORPH OF THE BLUE CRAB, CALLINECTES SAPIDUS RATHBUN (DECAPODA: PORTUNIDAE)

¹ National Marine Fisheries Service, Oxford Laboratory, Oxford, Maryland 21654
² Maryland Department of Natural Resources, Tidewater Administration, Oxford, Maryland 21654

The anatomy and histology of a gynandromorphic blue crab, Callinectes sapidus, are described. This is the first bilateral gynandromorph reported in a species of the Brachyura. Externally there was perfect bilateral division into male and female sides. The gonad on the male side was morphologically and histologically normal, but an AVD (anterior vas deferens) had been differentiated on the female side, and spermatogenesis was occurring through much of the female gonad. However, oogenesis was taking place in the apical portions of the gonadal lobes and a normal seminal receptacle was present. The crab had copulated as a female and may have copulated as a male.

Function of the malacostracan AG (androgenic gland) in control of maleness is discussed. It is concluded that sexual differentiation in malacostracan species exhibiting bilateral gynandromorphism must depend on complex mechanisms. External sexual characters may be determined very early in embryogenesis, but differentiation of the gonads is apparently influenced by the AG and other parts of the hormonal systems.