Development to third-stage larvae occurs in the eggs of Anisakis simplex and Pseudotetranova decipiens (Nematoda, Ascaridoidea, Anisakidae)

Abstract

Two moults occur during larval development in the eggs of Anisakis simplex (Rudolphi, 1809) and Pseudoterranova decipiens (Krabbe, 1878) from the North Atlantic. Live larvae forced out of eggs in sea water by coverslip pressure shortly before spontaneous hatching were surrounded by the thin cuticle of the first-stage larva. Infective larvae from naturally hatched eggs are loosely ensheathed in the thick cuticle of the second-stage larva. Thus, it is the third-stage larva that emerges from the egg of both species and not the second-stage larva as previously believed. The thin, smooth, fragile cuticle of the first-stage larva remains in the egg. The striated, cocoon-like cuticle of the second-stage larva of A. simplex may increase the buoyancy of the third-stage larva. The tail tip of the cuticle of the second-stage larva of P. decipiens is sticky and adheres the sheathed third-stage larva to the substrate.