ONTOGENY OF FOREGUT IN THE TROPICAL FRESH-WATER CRAYFISH, CHERAX-QUADRICARINATUS VONMARTENS, 1868 (PARASTACIDAE, DECAPODA)

The comparative morphology of the foregut during development from embr yonic larva to adult in Cherax quadricarinatus was examined by light a nd scanning electron microscopy. Major ontogenetic changes occurred in the gastric mill dentition in terms of denticle shape, appearance of vertical ridges in the lateral teeth, roughness of masticating surface s, degree of sclerotization and proportional sizes of the median tooth components. Natural food types appropriate for the various life histo ry stages during artificial rearing of C. quadricarinatus may be infer red from the morphology of the gastric mill dentition of those stages. Cardiopyloric valves and the gland filter appeared prior to developme nt of functional gastric mill teeth. Compared with the foregut of adul t astacid crayfish, that of adult C. quadricarinatus shows differences in the ventral cardiopyloric valve, pyloric funnel and lateral valves .