Development and functional morphology of the foregut of larvae and postlarvae of Petrolisthes armatus (Gibbes) (Decapoda, Porcellanidae)

Abstract

Previous studies on foreguts of the transitional stages have revealed complete absence of ossicles of the gastric mill in anomuran crabs, suggesting non-feeding behavior in this stage. In order to verify non-feeding behavior might occur in other anomuran species, the present work gives a detailed description of the foregut during the development of the porcellanid P. armatus. The foregut of the zoea I and II are structurally similar. They are morphologically simple, chitinous and lacking hard structures, but apparently functional. However, a significant change is observed in the foregut after metamorphosis into megalopal stage. In this change, the cardiac chamber shows a complex gastric mill supporting two lateral teeth and the pyloric chamber has a filter press relatively small, but specialized. These structures become more complex and calcified in the juvenile I. Comparisons between these characteristics and functionality of the P. armatus foreguts with other anomuran species, previously reported, are discussed.