Reproduction in Female Razorback Musk Turtles (Sternotherus carinatus: Kinosternidae)

Reproduction in female razorback musk turtles, Sternotherus carinatus, from southeastern Oklahoma and central Arkansas was examined. At both sites ovulation apparently occurs from late April or early May to at least earlyJuly, with 2 or 3 clutches typically produced per year. Arkansas females grow faster than Oklahoma females, reach maturity at larger sizes (95-100 versus 85-90 mm carapace length) but younger ages (after 5-6 versus 8 winters), reach larger adult sizes (mean carapace length 117 versus 102 mm), produce heavier eggs (5.7 versus 5.2 g), and bigger (3.8 versus 2.3 eggs) and heavier clutches (21.6 versus 11.6 g). For both populations, clutch size increases with body size; egg size also increases with body size, but the relationship is weaker. Unstandardized egg and clutch size exhibit no clear relationship; however, when effects of body size are removed, egg size and clutch size are negatively correlated. Clutch mass relative to body mass does not differ between sites, but relative egg size is greater in Oklahoma.