Post-metomorphic Growth and Reproduction in the Eastern Narrowmouth Toad (Gastrophryne carolinensis) from Northeastern Arkansas

Post-metamorphic growth and the reproductive cycle of the eastern narrowmouth toad (Gastrophryne carolinensis) were studied from 204 individuals collected during the April August 1989 activity season in a two-county area of northeastern Arkansas near the northwestern edge of the species\u27 geographic range. Late summer metamorphs require a full growing season before they can reproduce as they approach their second year of life. The oldest individuals may be at least five years old. By late April, gonadal cycles of adults had commenced; the males were producing sperm, and some of the females were gravid. Fertility of both sexes increased during the season and peaked in June. Males remained fertile through August, but only two gravid females were found after June indicating that adults were physiologically capable of breeding for a period longer than weather conditions were acceptable for oviposition. Neither clutch size nor ovum diameter increased with female body size. Disparity of body size and clutch characteristics throughout the brief breeding season could be explained by deposition of partial clutches. The growth, maturity, and gonadal cycle of this species at the northern edge of its range are similar to findings in southern populations, and climate, not changes inbreeding physiology, constrain breeding at this northern site

Female Reproductive Traits in Selected Arkansas Snakes

Female reproductive characteristics of 17 genera of Arkansas snakes (27 species and subspecies) were examined. Most of the snakes (n= 495) were collected over a 10-year span (1984-1993). Methods used to estimate clutch and/or litter size were as follows: 1) counts of previtellogenic ovarian follicles,2) counts of vitellogenic ovarian follicles,3) counts of oviductal eggs or embryos, 4) counts of corpora luteal scars, and 5) counts of neonates from egg clutches or litters. In several species, Method 1 tended to overestimate clutch size as determined by Method 2 by as much as 100% (e.g., in Diadophis punctatus, Elaphe obsoleta, and Lampropeltis getula), whereas these methods produced similar counts in Virginia striatula and Thamnophis proximus. The largest clutch size as estimated by Method 1 was 79 ova in a 744 mm in snout-vent length (SVL) individual of Thamnophis sirtalis; the smallest clutch size as recorded by this method was in Carphophis vermis (2 ova; 182 mm in SVL). Method 2 reduces the total egg count by one third over Method 1 in most species, and this count was very similar to the estimates obtained by Method 3, the most reliable way to estimate clutch or litter size (without actually having counts from egg clutches or litters). The presence of atretic ovarian follicles accounts for discrepancies found between clutch size estimates using Methods 1 and 2 as compared to Method 3. Comparisons of clutch sizes in Arkansas specimens to those recorded for snake species in neighboring states revealed similar sizes in 13 species; counts were larger in 8 species from Arkansas and smaller in only one species