Comparative morphology and development of bony elements in the head region in three species of Japanese catfishes (Silurus: Siluridae; Siluriformes)

The shape and development of bony elements of the neurocranium and suspensorium were studied in three species of Japanese catfish (Silurus) from the viewpoint of comparative morphology. InS. asotus andS. biwaensis the order of appearance of the bony elements was similar, but the ossification of most elements was delayed inS. lithophilus. The neurocranium and Suspensorium of adultS. lithophilus retain juvenile features compared with the other two species. On the other hand, in the skull ofS. biwaensis the sagittal crest of the supraoccipital, the ridge of the pterotic, and the hyomandibular process are more developed than in the other two species.