Development of mesonephros in prolarvae of acipenserids (acipenseridae)

Development of the excretory system in early ontogenesis of acipenserids—the Russian sturgeon Acipenser gueldenstaedtii, the starred sturgeon A. stellatus, the sterlet A. ruthenus, and the great sturgeon Huso huso—is investigated histologically. In acipenserids, the mesonephros develops after hatching. At the 36th stage of development (after Detlaf et al., 1981), the mesonephros is a consecutively arranged group of spherical rudiments of placodes situated along the Wolffian duct. Morphological differentiation of mesonephros as the first generations of renal corpuscles, vascular glomeruli, and convoluted tubules is completed up to the 45th stage, i.e., to the moment of transition of prolarvae to active feeding.