GROWTH OF YARROW SPINY LIZARD, SCELOPORUS-JARROVI (PHRYNOSOMATIDAE)

Growth of Sceloporus jarrovi was estimated using regression analysis o f size frequency changes from large samples. Mean SVL of neonates was 28 +/- 0.99 mm (range 26-30 mm); mean weight at birth was 0.80 +/- 0.0 7 g (range 0.62-1.02 g). Larger females had larger litters and gave bi rth to neonates of greater birth weight than did smaller females. On a verage, young-of-the-year experienced an increase in SVL of 32 mm and an increase in weight of 7.2 g to reach a SVL of 60 mm and a weight of 8 g by their first aggregation period. At all ages, males grew faster than females. Maximum size recorded for males was 99 mm SVL, 35.3 g a s compared to 97 mm SVL, 34.4 g for the largest female.