Under the 1931 classification system drawn up by Johannes Thiele, the class Gastropoda was divided … See more

The reduction or loss of the shell, the elaboration of the head, foot or mantle, and the acquisition of chemical defences are evolutionary trends shared by most opisthobranch taxa.
The loss of … See more

Opisthobranchia represents a morphologically diverse group of gastropods occupying a great variety of ecological niches. Opisthobranchs have a global distribution, but are restricted almost exclusively … See more

Principally soft-bodied marine creatures with a reduced or absent shell and no operculum, opisthobranchs use other methods for protection. The group has a diverse variety of highly specialized auxiliary de… See more

Opisthobranchs may be herbivores, detritivores or carnivores. Being slow, the carnivores hunt sedentary prey. They may eat bryozoans, Cnidaria, or sponges, absorbing the sponge toxin for defensive purposes. … See more