The time–temperature relation of embryonic development in the northwestern salamander, Ambystoma gracile

Publisher Website
Google Scholar
Abstract
A field and laboratory study on temperature-related embryonic development of Ambystoma gracile was made on a population from northwestern Washington. Natural spawning began in the beaver pond during early March, and the duration of embryonic development (stages 1 to 46) was about 62 days. Average water temperature in the pond during embryonic development was 8.5 °C (range, 4.4 to 14.3 °C). The laboratory data of embryonic development at constant temperatures show that the limits of temperature tolerance are about 5 to 22.5 °C. Rate of development was measured by determining time required to develop from first cleavage (stage 2) to gill circulation (stage 37); representative rates are 12.7 days at 20 °C, 27 days at 12 °C, and 89 days at 7 °C. Embryos of A. gracile have the slowest rate of development when compared with embryos of four other species of Ambystoma (maculatum, mexicanum, tigrinum, and jeffersonianum) and with embryos of three Pacific Northwest frogs (Ascaphus truei, Rana aurora, and Hyla regilla).