Fig. 2

Embryos of the pantropical spotted dolphin (Stenella attenuata) covering approximately weeks 4 to 9 of embryonic development. The first embryo shows forelimbs but not hind limbs (in most mammals forelimbs develop before hind limbs). In the second embryo, hind limbs have started to form, but their development ceases and they slowly disappear as the embryo grows (third and fourth embryos). These embryos are not drawn to scale. The first embryo is 6 mm, the last one 17.5 mm in length