Figure 1.

Development of Pleurodeles waltl. The main developmental steps are shown and the relationship between developmental stage and age (number of days post fertilization = dpf) is indicated. Three periods of gonad formation are indicated: genital ridge (GR), bipotential gonad (BG) and gonad differentiation (GD). The thermosensitive period is the developmental window during which genetically female larvae (ZW) have to be reared at 32°C to obtain sex reversal.