THE TEETH OF TYPHLONECTES COMPRESSICAUDUS (AMPHIBIA, GYMNOPHIONA) DURING THE DEVELOPMENT

During the ontogenesis of Typhlonectes compressicaudus, several tooth rows develop themselves on the surface of the mandible and into the up per jaw. Each tooth develops in six stages (from a to f). Teeth are co nstituted by a pedicel and a crown separated by a collar. Before hatch ing, at stages 23 and 24, a row of dentary buds (stages b and c) devel ops itself. From stages 25 and 26, new rows are placed. At the end of the fetal phase (stages 28 to 31), teeth are disposed in quincunx and look like a rasp on the lower jaw. The more evolved teeth are always s ituated in the ventro-anterior rows. At larval stages (32 and 33), wea r traces are observed on the medioventral teeth. New dentary buds are always developing dorsaly. Into the upper jaw, only three rows are obs erved. No tooth will emerge. new-born, mandible still bring several we ared fetal teeth. The root of them can be reabsorbed. In the lower jaw , adult teeth, that present the same parts that fetal teeth, are obser ved on the dentary, premaxillary, splenial and vomero-palatine bones. Fetal teeth disappear. In Typhlonectes compressicaudus, fetal teeth pe rmit the animal grasping the uterine wall. Secretions and epithelial c ells are separated during the oral feeding in intra-uterine animals. T he development of fetal dentition is narrowly correlated to the develo pment and the metamorphosis of the gut.