Histomorphometry of urogenital system in Iranian cave barb (Iranocypris typhlops)

Iranian cave barb (Iranocypris typhlops) is a rare and unique species which as a small population occur in a cave within mountains around Dorrood, in Lorestan province. In this research, the urogenital system of this fish was investigated in terms of morphology and histology. A total numbers of ten specimens of this fish were captured (in spring and summer) and transferred to the laboratory where they were fixed and then different parts of their urogenital system were subjected to anatomical and histological considerations. The results showed that gonads are located over the swimming bladder and behind the digestive tract. Kidneys are also found as a cylindrical mass of tissues reside on the back beside the backbone. Histologically, the most apical region of the kidneys consists of lymphatic tissues, but in the body of gland scare numbers of renal corpuscles are observed. Testes and ovaries are seen as long, sac-like organs which occupy a large part of visceral cavity. From histological standpoint, the testes have scattered seminiferous tubules and functionally are unrestricted. The ovaries are also filled with varied-sized of follicles. The follicles are composed of a large occyte along with a thin layer of follicular cells. According to the results it seems that the reproductive cycle of this fish is seasonal.