Frogs seem to have a delayed Ontogeny, too, but the restructuring is much less drastic than insects.

Vertebrates go through several stages in their development while in the egg (or placental sack, which stands in for the egg). The develop a head, spine, and tail initially. Then they add front limbs and finally rear limbs. Frogs hatch from their eggs prior to the limb development stage and retain that neotenous legless form while tadpoles. They are essentially hatched as embryos and don’t assume their adult form until later.