The Blue-Tailed Skinks (Eumeces) of Two North Carolina Coastal Islands

Abstract

BOTH of the common blue-tailed skinks, Eumeces fasciatus Linnaeus and E. inexpectatus Taylor, occur apparently throughout the North Carolina Coastal Plain. Taylor (1935) recognized both species in collections from Kinston, New Bern, and Beaufort. He also identified a broad-headed skink, E. laticeps Schneider, from Beaufort. Since Beaufort is on the coast, and since New Bern and Kinston are on broad rivers of the coastal plain, it might be expected that all three Eumeces would have reached the islands of the North Carolina outer banks. This, however, is not the case, for at least on two of the islands, the skink population appears to be composed solely of E. inexpectatus. There are at hand small collections from Harkers Island (24 specimens) and Shackleford Banks (21 specimens). Both islands are in Carteret County, North Carolina. Shackleford Banks is one of the series of off-shore bars that forms the Outer Banks; at its western end, opposite Beaufort, it lies less than 2 miles off the mainland shore. Harkers Island is probably one of an older series of off-shore bars; it lies 3 miles east of Beaufort, between Shackleford Banks and the mainland. Of the 21 specimens from Shackleford Banks, the characteristic light lines are absent only from the 2 largest specimens; each of these has 32 scale rows around the middle of the body, and the median subcaudals are only 1.14 and 1.06 times the width of the adjacent scales. In none of the 19-lined specimens does the dorso-lateral line follow the 3rd scale row; in 16 specimens it is on scale rows 4 and 5 on both sides of the body, while in the other 3 it is confined to scale row 4 on one side, but follows rows 4 and 5 on the other. In no specimen does the lateral line follow the 6th scale row; it is confined to the 7th row in 3, follows row 7 and 8 in the remaining 16. In one of these it is on row 7 alone on one side, but on rows 7, 8 on the other. The specimens range in size from 43 mm. (snout-vent length) to 75 mm., averaging 60.8 mm. The number of scale rows around the middle of the body averages 31, 7 having 30 rows, 5 having 31, and 9 having 32. The ratio in width of the median subcaudal scales to the adjacent scales averages 1.16:1, ranging from 1.01:1 to 1.27:1. These latter measurements were made with an ocular micrometer on a binocular dissecting microscope; the method does not permit exactitude, and the ratios are to be taken as approximations only, which are, however, less subjective than the notation sub-caudals not distinctly widened. The series from .Harkers Island is similar, except for a tendency for the light lines to be confined to one scale row, and except for a slightly higher frequency of the lower number (30) of scale rows. In 23 of the 24 specimens the lines are sufficiently distinct to determine that neither the 3rd nor 6th