Scanning Electron Microscopy of the scale morphology in Cyprinid fish, Rutilus frisii kutum Kamenskii, 1901 (Actinopterygii: Cyprinidae)

The normal and lateral line cycloid scales of a cyprinid fish Rutilus frisii kutum Kamenskii, 1901 have been subjected to scanning electron microscopy technique to study their detailed structure. The scales have the general morphological characteristics of the cycloid scales. In the normal scale located below the dorsal fin, the focus lies on the anterior region with few mucous pores. There is a clear-cut demonstration between the anterior and posterior region. In the posterior part, the scale has several rows of pigmented granules (tubercles) with different shapes of round to oval, semi-oval and even oblong structure. On the dorsal side, some circuli bear teeth-like structures called lepidonts can be seen which help the scale in firm attachment to the skin. The circuli may also have calcium projections. The lateral line scale has a canal which characteristically lies along the anterior-posterior axis with anterior and posterior openings. The anterior opening is wider than the posterior one and is hidden by an evelike extension cantilevered over it. Based on the obtained results it could be concluded that the shape and size of lepidonts on the circuli crest, the position, shape and size of tubercles and the presence of both anterior and posterior radii may provide reliable taxonomic tools. Changes in the circuli pattern, breakage of the circuli, loss of lepidonts and tubercles may be used to access the habitat condition of this carp especially habitat pollution.