Morphological and functional study of the male reproductive tract in the shrimp pleoticus muelleri bate (decapoda, penaeoidea)

Abstract

Anatomical relationships and the histological structure of the male reproductive tract in Pleoticus muelleri were described by using light microscopy. The male reproductive tract consists of paired organs: testes and vasa deferentia with the terminal ampoule, which opens at the gonopores on the coxae of the fifth pair of pereopods. Testes are located dorsally in the cephalothorax and are comprised of two lobes surrounded by laminar connective tissue. They are composed of cystic structures (with spermatogonia or primary spermatocytes) covered by connective tissue. Each vas deferens consists of four morphologically different zones: the collecting tubule, proximal, medial, and distal (terminal ampoule). The collecting tubule connects the testes with the proximal zone and is lined by a shallow epithelium. The proximal zone, lined by a columnar secreting epithelium, is internally divided into two ducts by a septum. The biggest spermatophoric duct conveys the sperm mass, and the other secretes the acellular material that supports the sperm mass in the spermatophore. In the medial zone the ducts are incompletely separated by a partial septum and the epithelial cells secrete the hyaline layer of the spermatophoric matrix. The distal zone or terminal ampoule comprises four interconnecting chambers and is externally surrounded by connective tissue and a conspicuous layer of striated muscle. The spermatophore reaches complete maturation in the terminal ampoule.