Studies of the fishes of Lake Biwa-ko. I. Morphological study of the three species of catflshes of the genus Parasilurus from Lake Biwa-ko, with reference to their life
Tomoda, Y.
Japanese Jour Ichthyol 8(5/6): 126-146
1962
Accession: 025547621
In P. biwaensis the development of external sensory organs is rather poor except for the eyes, and the body as a whole is adapted for a pelagic carnivorous life; in P. lithophilus the sensory organs are well developed, and the body is adapted to a good extent for rupicolous life; in P. asotus two pairs of heavy barbels are present, the eyes are degenerate and the body is adapted for bottom life in shallow turbid water. Irrespective of the superficial variability of P. asotus, its specific peculiarity has become evident after many characters were examined as a combination. Such a combination of characters is always peculiar to P. asotus and is correlated with its mode of life, though respective characters are not stable according to the difference in external factors. Not giving proper consideration for ecological data we might fail to relaize the accurate status of P. asotus. Mere comparisons of specimens from various localities are of little importance unless studies on habitat and life are carried out. Future investigations in this line should be necessary on such problematical species of the genus Parasilurus as are spread over the Asiatic Continent.