GEOGRAPHIC VARIATION IN SELECTED LIFE HISTORY TRAITS OF THE EASTERN NARROWMOUTH TOAD, GASTROPHRYNE CAROLINENSIS (HOLBROOK, 1836), ALONG THE NORTHEASTERN EDGE OF ITS GEOGRAPHIC RANGE

We examined the Eastern Narrowmouth Toad,Gastrophryne carolinensis, along the northeastern edge of its geographic range in Virginia to determine the extent to which selected life history traits in this region adhered to patterns associated with a latitudinal gradient in this species. As in studies elsewhere, a significant difference in mean adult body size between males (28.3 mm SVL) and females (30.1 mm SVL) was typical of this species as was the absence of a relationship between clutch size and female body size. Mean body sizes of both sexes appeared larger in northern populations than southern counterparts. Geographically predictable, the breeding season in Virginia was severely curtailed in response to climatic constraints despite extended fertility, and its breeding activity peaked in mid-summer as it has been reported to do throughout its geographic range. Thus, along the northern edge of its geographic range, the Eastern Narrowmouth Toad retains its ability breed for a longer season despite present climatic constraints, an advantage in the face of climate change that could alter timing and duration of acceptable breeding atmospheric conditions

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

Reproduction and Larval Development in the Marbled Salamander, Ambystoma opacum (Caudata: Ambystomatidae), from Arkansas

Field investigations of the reproductive biology and larval growth and development in Ambystoma opacum from northeastern Arkansas began in early October, 1987 at the onset of nesting activities, and concluded in early May, 1988 when larval transformation occurred. The onset and timing of clutch deposition were documented. Clutch size averaged 107.1 eggs and was not significantly correlated with snout- vent length (SVL). The incubation period was estimated to be 90 days. Larvae grew at an average rate of 6.3 mm SVL per month. Metamorphosis, in early May, occurred at an average SVLof 30.5 mm. Larval development was recorded by noting the chronological appearance of digits on limb buds as well as noting the change in body color patterns. Premetamorphs characteristically retained a ventrolateral row of white spots throughout development. Postmetamorphs eventually lost these spots and developed a color pattern totally unlike adults