Sk. Mboko et al., ASYMMETRY OF MOUTH-OPENING OF A SMALL HERBIVOROUS CICHLID FISH TELMATOCHROMIS-TEMPORALIS IN LAKE-TANGANYIKA, Zoological science, 15(3), 1998, pp. 405-408
Direction of mouth-opening of a small herbivorous Tanganyikan cichlid,
Telmatochromis temporalis, was studied. Each sample fish opened its m
outh either rightward or leftward in some degree. The directions of mo
uth-opening were independent of the body curve directions, and the asy
mmetry will be due to asymmetric mouth morph individually specific. Th
e degree of the mouth asymmetry was not related to body size, suggesti
ng the asymmetry being not acquired characters. No fish opened the mou
th in lateral symmetry, indicating that the asymmetry is different fro
m ''fluctuating asymmetry''. This fish took algae on rock surface usua
lly using right or left side of its mouth. However, strong relations b
etween directions of mouth-openings and frequencies of mouth side used
in foraging were not found, and the biological role of the asymmetry,
if any, is not clear now.