Systematics: Originally described as Testudo reticularia by Pierre-Andre Latreille in 1801 from a specimen (now lost) collected between 1798 and 1800 in "Carolina." Harper (1940) restricted the type locality to Charleston, South Carolina. Louis Agassiz (1857) first used the genus Deirochelys for this species. All Virginia authors have used the current nomenclature. Three subspecies are recognized: D. reticularia chrysea Schwartz, D. reticularia miaria Schwartz, and D. reticularia reticularia (Latreille). The distributions of these races were illustrated in Zug and Schwartz (1971) and Conant and Collins (1991). Only the nominate subspecies is found in Virginia.

Description: A moderate-sized freshwater turtle reaching a maximum carapace length (CL) of 254 mm (10 inches) (Conant and Collins, 1991). In Virginia, known maximum CL is 200 mm, maximum plastron length (PL) is 180 mm, and maximum body mass is 974 g.

Morphology: Carapace elongated and high-domed; carapacial surface rough with numerous longitudinal ridges (striations); marginals 12/12, pleurals 4/4, and vertebrals 5; cervical scute narrow; 1st vertebral scute contacts cervical and 4 marginal scutes; hingeless plastron 88-91% of CL; head and neck long, nearly length of carapace when fully extended.

Coloration and Pattern: Carapace brown to olive with a reticulate (netlike) pattern of yellow to light brown; black spots may be present on ventral side of the marginal scutes, especially posteriorly; hingeless plastron plain yellow with a poorly defined, faded blotch posteriorly on it in some individuals; an elongated black stripe occurs on bridge on some individuals but is absent in others; neck with thin yellow stripes on black skin; each foreleg with a broad yellow stripe anteriorly; vertical alternating yellow-and-black stripes on rear of thighs.

Sexual Dimorphism: Five adult females from the Virginia population averaged 182.6 ± 17.7 mm CL (153.7-200.0) and 165.4 ± 16.1 mm PL (139.1- 180.0). Two females weighed 523 g and 974 g. Three adult males averaged 128.4 ± 14.3 mm CL (117.8-144.6), 112.9 ± 14.2 mm PL (103.4-129.2), and 281.7 ± 97.2 g body mass (205-391). Sexual dimorphism index based on CL was 0.42. Females have higher domed shells than males. The cloacal opening extends beyond the posterior edge of the carapace in males. Precloacal tail length in one female was 6.2 mm and was 15.2-22.2 mm (ave. = 19.0 ± 3.5) in three males.

Juveniles: Juveniles are colored and patterned as adults but are brighter. Hatchlings from Florida were 28-32 mm PL (ave. = 30.1) and weighed 8.1-9.0 g (ave. = 8.5) (D. Jackson, 1988). No Virginia hatchlings have been found.

Confusing Species: No other Virginia turtle has such a long head and neck. Chrysemys picta has a flattened shell, brightly colored marginals, and usually 2 yellow spots behind each eye. Pseudemys rubriventris has reddish vertical streaks on the pleural scutes and Trachemys scripta has a yellow vertical bar or reddish patch behind the eye. The 1st vertebral scute contacts the cervical and 2 marginals in these species.

Geographic Variation: None in Virginia. Schwartz (1956b) described the variation in color and pattern in each of the three subspecies.

Biology: In Virginia, the Chicken Turtle occupies freshwater, interdunal, cypress ponds. Elsewhere in its range it inhabits ponds, lakes, ditches, and cypress swamps (Ernst and Barbour, 1989a). It is a basking turtle. J. W. Gibbons (pers. comm.) has captured these turtles in every month of the year in South Carolina, although they have been most abundant in March and April. Terrestrial movement occurs in both sexes in the Virginia locality, and some individuals spend considerable time on land just beneath the ground surface (K. A. Buhlmann, pers. comm.)

Ernst and Barbour (1972) noted that Chicken Turtles are omnivorous and have been observed to eat crayfish, tadpoles, and aquatic plants, but D. Jackson (1988) stated that it is a "strict carnivore that feeds primarily on arthropods." A single road-killed specimen from the Virginia population had eaten a crayfish and a carabid beetle.

Except for the observations that a road-killed female contained oviductal eggs on 20 May 1964 and one live female was gravid on 1 June 1991 (K. A. Buhlmann, pers. comm.), no reproductive information is available for Chicken Turtles in Virginia. The following information is derived from Gibbons (1969), Gibbons and Greene (1978), and Congdon et al. (1983). Clutch size was 5-11 eggs. Eggs averaged about 35 x 21 mm. Females laid up to two clutches per year, one in early spring and one in fall. The earliest egg-laying date in South Carolina was mid-February. Size at maturity was 141-154 mm PL for females and 75-80 mm PL for males. Nesting ecology is unknown. Hatchlings, especially those of fall eggs, overwintered in the nest and emerged in the spring. In Florida, clutch size was 2-19, number of clutches per season was two to four, incubation period was 78-88 days, and nesting extended from late September to mid-March (D. Jackson, 1988).

The biology of the Virginia population is unknown and it has been little studied elsewhere compared with other turtle species. Gibbons (1987) determined that most adult Chicken Turtles in South Carolina lived to be greater than 10 years of age and some reached 20 years.

Remarks: The Chicken Turtle was first discovered in Virginia on 22 August 1958 by Roger H. de Rageot and W. Leslie Burger, who found a skeleton at Cape Henry (de Rageot, 1968). It was apparently common in the early 1970s (C. A. Pague, pers. comm.), but efforts during 1989-1992 failed to record more than nine live individuals. Whether the northern Virginia Beach population is natural or an introduced one is an open question. However, the unconfirmed sighting of D. reticularia in lower City of Chesapeake (G. W. Williamson, pers. comm.) and the presence of natural populations of this species in Nags Head Woods, North Carolina, in similar habitat (Braswell, 1988) suggest a natural occurrence. An appropriate study comparing populations in the Coastal Plain is warranted.

Conservation and Management: The Chicken Turtle was officially listed as endangered under Virginia's endangered species law on 1 October 1987. Predation by raccoons (Procyon lotor) and Snapping Turtles (Chelydra serpentina), both abundant in the Seashore State Park, is probably the chief cause of mortality. Additional mortality is occasionally caused by vehicular traffic. Human activity in the park may disturb females laying eggs (Mitchell and Buhlmann, 1991). If all known living adults are 10 years of age or older, and most die by age 25 (see "Biology"), then in 10-15 years there may be no Chicken Turtles left in Seashore State Park. This assumes no juvenile recruitment, a distinct possibility since no juveniles or immature individuals have been seen or captured despite considerable search effort. Active management (removal or translocation) of the two primary predators may enhance the survival of the Chicken Turtle population. This small population should be frequently monitored.