title: Anatomical and functional differences in the Adductor mandibulae muscle between Zaco platypus and Carassius gibelio langsdorfi of the Cyprinidae family.
abstract: A histological study has been made on the jaw-closing muscle, Adductor mandibulae, of 2 species of Cyprinidae, Zaco platypus and Carassius gibelio langsdorfi, which show completely different feeding behaviour. The former swims up to the food with its mouth open in rapid current, and the latter sucks food from the bottom into its mouth by enlargement of the buccal and opercular cavities in quite mild current. The latter's feeding behaviour was made repeatedly. The A. mandibulae was divided into its anterior and posterior parts in both fish. The anterior part in Z. platypus was divided into 2 portions, and that of C. gibelio langsdorfi into 3 portions. In each portion of the muscle of both fish, SDH activity in the muscle fibers decreased from the medial to the lateral side. Both fish had 3 types of the fibers on the basis of SDH activity, whereas the combinations of each fiber type were more complex in C. gibelio langsdorfi than in Z. platypus. Moreover, the ratio of fibers with higher SDH activities was larger in C. gibelio langsdorfi than in Z. platypus. And, differences in the number of capillaries per fiber in the same fiber type between the 2 fish suggest a complex adaptation of the jaw-closing muscle to the environmental circumstances of the fish.
mesh_terms: D000818:Animals; D005075:Biological Evolution; D003530:Cyprinidae / Q000502:physiology*; D005247:Feeding Behavior / Q000502:physiology; D008334:Mandible / Q000033:anatomy & histology / Q000502:physiology*; D008410:Masticatory Muscles / Q000033:anatomy & histology / Q000502:physiology*; D013045:Species Specificity; D013385:Succinate Dehydrogenase / Q000378:metabolism
chemical_list: D013385:Succinate Dehydrogenase