Histogenesis and morphological characteristics of hyaline cartilage of the pumpkinseed juveniles Lepomis gibbosus (Linnaeus, 1758) (Actinopterygii, Centrarchidae)

The article presents the structure feature of the hyaline cartilage of two-month-old fry of the pumpkinseed Lepomis gibbosus (Linnaeus, 1758). It is found that 4 cm long fry have cartilaginous skeleton, in which the bony tissue is replacing cartilage one. It is noted that the chondroblasts have a flattened or oval shape and reach a size of 77.10 ± 25.55 μm 2. Eventually, the growth of the cytoplasm of cells and the differentiation of chondroblasts into chondrocytes leads to the decrease in nuclear-cytoplasmic ratio from 0.159 to 0.086 units. The definitive chondrocytes reach a size of 142.82±14.78 μm2, which is almost twice as large as chondroblasts. However, the dimensions of the nuclei of cells of the cartilaginous tissue are not statistically different and range from 11.4 to 11.8 μm2. As the fish grows, the bony tissue gradually replaces cartilage tissue of the skeleton, involving chondroclasts. The study was carried out within the research scientific work "Assessment of the physiological, biochemical and cytological status of native and alien aquatic organisms under conditions of anthropogenic transformation of aquatic ecosystems" (state registration number 0117U006751).