(Gray, 1863a)
Yellow-margined box turtle
Recognition
This is a species of Cuora with a high arched shell and a distinct yellow vertebral stripe. The carapace (to 19.5 cm) is domed, widest behind the center, and smooth bordered. Each vertebral is narrower than its adjacent pleural scute. A prominent vertebral keel is present, as are also two disrupted, low, lateral keels. Well-marked growth annuli may be present on each carapacial scute. The carapace is usually dark brown with a bright-yellow vertebral stripe, a reddish brown blotch on each pleural and vertebral, and a yellow or reddish brown blotch along the outer border of each marginal. The dark-brown to black plastron has a narrow yellow band along the outer border of the humerals, pectorals, abdominals, and femoral Undersides of the marginals are yellow. The posterior lobe is wide, not notched posteriorly, and capable of entirely closing over the hindlimbs and tail. The plastral formula is: abd > an > pect > gul > hum > fem. Between the anal scutes, the seam is often reduced or absent in older individuals. The head is gray to light greenish dorsally with a broad yellow stripe running backward from the orbit to the neck. Upper jaws and sides of the head are yellow and the chin is either pink or yellow. Upper jaws are hooked. Limbs are grayish brown on the outside with yellow sockets. Heels of the hind feet are yellow. Forelimbs are covered with large scales. The short tail is gray with a faded yellow dorsal stripe. Numerous blunt tubercles occur at the base of the tail.
The diploid chromosome total is 52 (Kiester and Childress, in Gorman, 1973).
In males the plastron is rounded in both front and back; that of females is slightly bent upward in the rear. Also, the male's tail is thicker at its base than that of the female.
Distribution
Cuora flavomarginata is known from southern China, Taiwan, and the Ryukyu Islands (Ishigaki Shima, Iriomote).
Geographic Variation
Three subspecies are recognized by McCord and Iverson (1991) and Iverson (1992). Cuora flavomarginata flavomarginata (Gray, 1863a), the common yellow-margined box turtle from Taiwan, has a small to moderate (34% of anterior-posterior scute length) light blotch on each pleural scute, a short abdominal scute, and usually 10-11 rows of enlarged scales on the anterior surface of its forelimbs. The Chinese yellow-margined box turtle C. f. sinensis (Hsü, 1930) resides in mainland China. It has a small to moderate (35% of scute length) blotch on each pleural scute, a relatively short abdominal scute, and usually 8-10 rows of enlarged scales on the anterior surface of each forelimb. The Ryukyu yellow-margined box turtle C. f. evelynae Ernst and Lovich, 1990 from the Ryukyu Islands, Japan has a large pleural blotch (65% of scute length) that often coalesces with adjacent pleural blotches to form a longitudinal light stripe along pleurals 2-4, a relatively long abdominal scute, and 8-10 rows of enlarged scales on the anterior surface of each forelimb.
Habitat
Cuora flavomarginata usually occurs in ponds and rice paddies, but Mao (1971) reported it from an upland shaded stream on a forested hill in Taiwan. The sides of the stream were overgrown with extremely luxurious high-stemmed vegetation, and under the vegetation of the damp bank about 100 specimens were collected in one morning.
Natural History
Courtship involves the male approaching and facing the female while bobbing his head. He then moves his head and next his entire body under the female, which itself remains passive (Lorenz, 1985).
In captivity, up to three clutches of 1-3 eggs may be laid between March and July; the period between two clutches may be as short as six days (Fukada, 1965; Zwartepoorte, 1991; Becker, 1996). The white eggs are oval to elongated, ranging from 35-58 mm in length and 16-26 mm in width (Fukada, 1965; Zwartepoorte, 1991; Becker, 1996). Incubation takes 68-72 days at 30°C (Zwartepoorte, 1991), but may take up to 101 days at 28°C (Becker, 1996). Hatchlings have carapaces of approximately 40 mm with a conspicuous yellow keel.
Cuora flavomarginata is fond of basking and spends much time on land, but, when disturbed, quickly pulls into its shell and closes the plastron. In captivity it readily feeds on a variety of foods ranging from fish and meat to bananas.
IUCN Red List Status (1996)
Vulnerable (A2c).