RATITE-LIKE NEOTENY INDUCED BY NEONATAL THYROIDECTOMY OF EUROPEAN STARLINGS, STURNUS-VULGARIS

The Ratites (ostriches, emus, etc.) are thought to be neotenous descen dants of flying birds, rather than primitive birds, even though they b ecame a separate group early in the evolution of birds. This is becaus e of the juvenile, rather than primitive, condition of the palate, sku ll-sutures and feathers. We report here that European starlings (Sturn us vulgaris) thyroidectomized soon after hatching also show neoteny, r etaining many juvenile features (general morphology, palate, skull-sut ures, feathers, behaviour), while at the same time becoming sexually m ature. The juvenile characters were similar to those found in Ratites, suggesting that hypothyroidism may have been a factor in the evolutio n of the Ratites.