|
Tooth Replacement Rate of Carcharodon carcharias (Linneaus, 1758)
ABSTRACT: Analysis of 31 jaws of Carcharodon carcharias, from specimens ranging in total length from 143.5 to 460.9 cm, finds a range in tooth replacement rate of the Second Lateral tooth family of (Upper/Lower) 106.24/113.59 days for young individuals to 225.90/242.18 days for old individuals using the Strasburg Plot Method.
The Second Lateral tooth family of the upper and lower jaws gives the best estimates of tooth replacement rate. Upper and lower jaws demonstrate fluctuating asymmetry within the number of tooth positions. The range in dental formulae of the upper/lower jaw for this sample is: 11 to 15 - 0 - 12 to 14 / 11 to 16 - 0 - 11 to 15. One male (NOAA-NMFS Tag #610, TL 149.5 cm) taken off New Jersey in the Northwest Atlantic, has a very minute parasymphysial tooth in the upper right jaw.
This is the first report of a parasymphysial tooth present in a White Shark and is considered here as an atavistic character. Using the tooth replacement rate of 106.24 days/tooth, and previous reports of near term White Shark embryos with 3 to 4 full tooth sets present in their alimentary canals, an estimate of when tooth replacement begins prior to parturition and therefore a minimum estimate of gestation period for the White Shark can be calculated as 425 days.
Information provided by John C Bruner
|