Mitchell, Janet

4 publications

Mitchell, Janet (detail)
1973Determination of relative age in the dugong Dugong dugon Müller from a study of skulls and teeth.
Zool. Jour. Linn. Soc. 53(1): 1-23. 10 figs. Aug. 1973.
—A study of skull, mandible, and dental variates in 41 northeastern Australian dugongs indicated the presence of three age classes, "juveniles", "adolescents", and "adults". Several of these features may reflect sexual dimorphism.
Mitchell, Janet (detail)
1976Age determination in the dugong, Dugong dugon (Müller).
Biol. Conserv. 9(1): 25-28. 1 fig. Jan. 1976.
—Summary of Mitchell (1978).
Mitchell, Janet (detail)
1978Incremental growth layers in the dentine of dugong incisors (Dugong dugon (Müller)) and their application to age determination.
Zool. Jour. Linn. Soc. 62: 317-348. 10 figs. 2 pls. Apr. 1978.
—Concludes from a study of Australian dugong tusks that sexual maturity is reached at about 10 growth layers (= 5 or 10 years of age) and that the life span is just under either 30 or 60 years. Tooth succession in the upper jaw is correlated with number of growth layers in the tusks.
Mitchell, Janet (detail)
1981The coincidence between a distinct accessory groove in young dugong teeth and a tropical cyclone.
Biol. Conserv. 20(2): 99-109. 1 tab. 3 figs. June 1981.
—Analyzes the annual layers in the tusks of 4 young Queensland dugongs, discusses the formation and identification of neonatal lines and other types of layering, and shows that a growth disturbance coincided with a cyclone in January 1965.