Epitheliophagy: intrauterine cell nourishment in the viviparous alpine salamander, Salamandra atra (Laur.).

The intrauterine nourishment of the viviparous alpine salamander, Salamandra atra, has been demonstrated to consist of two phases: oophagy - after hatching from the jelly membrane, the developing embryo ingests the remaining disintegrated, unfertilized egg mass. Epitheliophagy - a special cranial portion of the uterus wall, the zona trophica, is stimulated by the presence of the embryo. After the yolk mass has been exhausted, the developing embryo is supplied with epithelial cells as nourishment until the end of pregnancy. The epithelial cells of the zona trophica are released into the uterus lumen by partial necrosis of the underlying connective tissue. Regeneration and detachment of the uterine epithelium occur simultaneously in different regions of the zona trophica. A special dentition enables the embryo, according to its position in the uterus, to feed directly on the zona trophica.