Tooth replacement in the red-backed salamander, plethodon cinereus

✍ Scribed by Ronald Lawson; David B. Wake; Nancy T. Beck

• Publisher: John Wiley and Sons
• Year: 1971
• Tongue: English
• Weight: 810 KB
• Volume: 134
• Category: Article
• ISSN: 0362-2525
• DOI: 10.1002/jmor.1051340302

✦ Synopsis

Abstract

The developmental cycle of the teeth in Plethodon cinereus is analyzed on morphological grounds using alizarin preparations. All the stages in development do not occupy the same proportion of the life cycle time. Functional teeth and germs at an early stage in development occupy a large proportion of the life cycle time, whereas the processes of tooth shedding and ankylosis occur very quickly. The time during which any locus does not bear a functional tooth, and is therefore a non‐functional locus, is reduced to a minimum. P. cinereus has a basic pattern of tooth replacement which is consistent with Zahnreihen which are 2.0 tooth spaces apart. Variations in the replacement pattern are common and these are produced by relatively small fluctuations in the spacing of the Zahnreihen around the „mean„ of 2.0. Localized disturbances which produce breaks in the replacement pattern and cause waves to cross also occur. These may be due to the failure of tooth germs to develop, the fusion of tooth germs, or may be the result of the inherent variability in a complex biological system. This variability causes individual tooth germs to develop too slowly or too quickly and hence assume an „abnormal”︁ position thus causing breaks in the replacement pattern. Tooth replacement may be controlled by an intra‐local mechanism(s) rather than by stimuli which travel along the jaw.