The rockhopper blenny Andamia tetradactyla (Blenniidae) demonstrates terrestrial spawning in supralittoral zones of reefs, the eggs developing fully even in rocky hole nests that are submerged for only a short time during high tide. To ascertain how such eggs tolerate aerial conditions, their morphological characteristics were investigated by SEM (scanning electron microscope). The chorion was thick comprising seven lamellae, and the egg surface covered by clasping filaments forming an “adhesive disc”. These allowed the deposited egg to remain firmly attached to the substratum, even when battered by wave at high tide. Moreover, some surface parts of the chorion remained at the adhesive site in the nest, after hatching. It is likely that these species-specific morphological characteristics of the eggs of A. tetradactyla developed as adaptive phenotypes in alternate conditions of dryness and turbulent water movement.
