Ageing the eggs and embryos of the pig-nosed turtle, Carettochelys insculpta (Chelonia: Carettochelydidae), from northern Australia

Abstract

Standard series of embryonic stages are the primary basis for organising information in embryological studies and for ageing eggs and embryos in field studies. In this paper we calibrate the developmental series for the pig-nosed turtle, Carettochelys insculpta, from northern Australia against an established series for Chelydra serpentina, carefully noting unique attributes of C. insculpta. We also extend existing non-destructive approaches to staging embryos by identifying several additional specific embryological attributes visible externally or by candling. A chronological sequence of attributes visible by candling is established as a viable alternative to the destructive approaches requiring direct examination of embryos.