| Popis: |
Age from skeletochronological analysis of phalanges, sex, weight, and snout-vent length were analyzed for a population of Bufo cognatus living in the high altitude San Luis Valley of south- central Colorado. Only one and two year old toads were found. In general, toad size increased with age although there was considerable overlap between age groups. Males were consistently smaller than females at all ages. A high proportion of false lines occurred in the 1987 season of growth and can be correlated with a drought that occurred during June and July of that year. Age and size distribution of fossil B. cognatus from Alamosa Formation sediments in the San Luis Valley were determined from skeletochrono- logical analysis of ilial shafts prepared as thin sections. Age structure of the fossil assemblages were similar to the modern; false lines in the fossil ilia may indicate summer drought during ancient times. |
