Plestiodon inexpectatus (Taylor)
Blue-tailed Skink, Scorpion (Mount 1975).
Formerly common statewide but believed to be declining and potentially threatened, especially in southern Alabama. Reasons for downward trend unknown. HIGH CONSERVATION CONCERN.
A brightly colored, medium-sized (16.5-2.4 cm [5.5-8.5 in.] long; max. snout-vent length = 89 mm [3.5 in.]) lizard (Conant and Collins 1991). In both sexes, tail slightly longer than body; breaks off when seized, but regenerates quickly. Adult males larger than females and ratio of head to body size greater in males than females (Vitt and Copper 1986). Covered with highly polished, overlapping scales (Mount 1975). Juveniles display bright blue tail and five prominent yellow to orange longitudinal stripes against a blackish to brownish ground color. Younger individuals display brighter stripes of oranges and reds on heads, noticeably contrasting with dull orange-yellow stripes on remainder of body (Palmer and Braswell 1995). The five lines are comprised of a singular mid-dorsal stripe, a pair of dorsolateral stripes, and a pair of lateral stripes (Mount 1975). In some juveniles, a pair of additional faint stripes running along the sides of the belly is visible (Palmer and Braswell 1995). Juvenile pattern may persist on mature females, but typically overall colors and patterns transform with age (Mount 1975, Conant and Collins 1991). At maturation, blue color of tail fades into a grayish or brown color, but a purplish hue may endure throughout life (Conant and Collins 1991). Stripes fade with age, but remnants remain in mature individuals. Older males may become a uniform bronze, tan, or olive ground color with broad, dark, lateral stripes. Heads of mature males typically swell and turn red or orange, especially on jaws. Very old males have completely red heads, but females do not (Mount 1975, Conant and Collins 1991, Palmer and Braswell 1995). In appearance, very similar to two other members of the “five-lined” skink group: the five-lined and broad-headed skinks. Colors and patterns alone are not useful characteristics to differentiate among these three species. However, the combination of five-stripes and a blue tail readily identifies younger individuals as members of this triad. Capture and inspection of midventral scale row located under the tail necessary to definitively and accurately classify individuals into one of these three species. Southeastern five-lined skinks have scales in this row that are nearly equal in width to adjacent scale rows, especially at the base in a non-regenerated portion of tail. In the other two species, this row is noticeably wider than adjacent scale rows at the base of tail (Barbour 1971, Mount 1975, Conant and Collins 1991, Palmer and Braswell 1995). Additionally, the dorso-lateral stripes of the southeastern five-lined skink cover the fifth (or fourth and fifth) scale rows, counting from the mid-dorsal row, but in the other two species the dorsolateral stripe is on the third and fourth (or fourth) scale rows (Barbour 1971; Martoff et al. 1980). Southeastern five-lined skink tends to have a narrower mid-dorsal stripe than the five-lined skink (Mount 1975). Electrophoretic data suggest the three form a monophyletic group with the southeastern five-lined skink and the broad-headed skink being the closest to a presumed common ancestor (Murphy et al. 1983).Southeastern five-lined skinks, occupying coastal islands and outer banks of North Carolina, have smaller scales around tail and body than mainland individuals (Palmer and Braswell 1995).
Southeastern in distribution from southern Maryland, Virginia, and Kentucky south to Florida Keys and southwest to southeastern Louisiana. Not found west of Mississippi River or north of the Ohio River (Conant and Collins 1991, Palmer and Braswell 1995). More abundant in the Coastal Plain, but inhabits a wide variety of physiographic provinces (Martof et al. 1980, Palmer and Braswell 1995). Occurs on southeastern coastal islands in both the Atlantic and Gulf; some of these islands have no freshwater and only sparse vegetation (Martoff et al. 1980, Conant and Collins 1991, Palmer and Braswell 1995). Although found throughout Alabama, uncommon or absent in both the Tennessee Valley and the chert belt of Alabama (Mount 1975). Mount’s (1975) distribution map suggests species may avoid floodplains of large rivers in Alabama, including the Alabama, Black Warrior, upper Tombigbee, and lower Cahaba. Mount (1975) mapped fewer occurrences from the relatively mesic confines of southeastern Alabama, south of the Tallapoosa River and east of the Alabama River, than in other parts of the state.
In Alabama, frequents xeric ridge tops and other places with well-drained sandy soils (Mount 1975). Can be found in dry, open woodlands and pine flatwoods, cut-over or open areas, especially along the edge between forests and openings. Uncommon within riparian floodplains and mesic upland slopes, ravines, and coves. Seeks refuge under logs, boards, or stones (Barbour 1971) and within sawdust piles, rotting logs, rock piles, and brush piles (Mount 1975, Palmer and Braswell 1995). Can be found scurrying along logs, stumps, trees, fences, and buildings, especially sawmills. The closely related five-lined skink prefers more mesic sites, but can be found together with the southeastern five-line skink (Mount 1975). The broad-headed skink is more arboreal than the southeastern five-lined skink (Mount 1975, Palmer and Braswell 1995).
LIFE HISTORY AND ECOLOGY:
Most active in spring, but was observed in every month except January in North Carolina (Palmer and Braswell 1995). Most active by day, seeking cover by night (Conant and Collins 1991). Natural prey items consist of arthropods and other invertebrates (Mount 1975); captives accept crickets, grasshoppers, mealworms, and neonatal mice (Palmer and Braswell 1995). At 21 months of age both males and females are sexually mature (Vitt and Cooper 1986). Females lay three to 11 eggs in April, May, June, or early July within cavities of rotting wood (logs, stumps, and sawdust piles), or in shallow depressions under a variety of cover (Mount 1975, Palmer and Braswell 1995). Females have been observed near nests until hatching occurs from July through August (Palmer and Braswell 1995).
BASIS FOR STATUS CLASSIFICATION:
In recent years, specimens have rarely been identified in Alabama. However, this may be due to the overlapping distribution of very similar species. As already mentioned, not being readily distinguishable from two other species of “five-lined” skinks found within its distribution makes it likely that more individuals are observed than are positively identified in the field. Current status of Alabama populations unknown.
Mark H. Hughes