Patterns of correspondence between skin rings and vertebrae in gymnophiona (Amphibia).

The skin annulation seems to have a direct relation with the vertebral column segmentation. The type of rings, primary, secondary, tertiary, or quaternary set by binary division, probably results in an induction process during morphogenesis. The diverse stages of this division appear and are rubbed out from front to rear. The topographical correspondence is different for 3 distinct parts of the body: the collar, the trunk, and the posterior part. In this last region, we can find a more or less reduced true tail or a terminal appendage without vertebral element. All these new morphological data support elements of functional indications.