Keeled box turtle
The elongated (to 18 cm), oval carapace is flattened dorsally and strongly serrated posteriorly. The anterior margin is also somewhat serrated. Three well-developed keels are present: a medial keel along the center of the flattened vertebrals, and two lateral keels extending along the dorsal portions of pleurals 1-4, forming a border on each side of the flattened dorsal area. Hexagonal neurals are short sided posteriorly. Vertebrals are usually wider than long, but the narrower 1st vertebral may be as long as or slightly longer than wide. The 12th marginals (supracaudals) on each side are smallest. Uniformly colored, the carapace ranges from yellowish or light brown to reddish brown or dark brown. The plastron is smaller than the opening of the carapace and cannot close completely; the single hinge occurs between the hyo- and hypoplastra (between the overlying pectoral and abdominal scutes). The entoplastron is crossed by the humero-pectoral seam. A posterior notch lies between the anal scutes. The plastron is united to the carapace by ligaments along a short, but distinct, bridge (approximately one-third as long as the plastron). Its buttresses are weakly developed. An axillary scute may be absent from the bridge. The plastral formula is: abd > an > pect > hum >< fem > gul. The plastron is yellow to light brown with a dark-brown spot on each scute. The head is of moderate size with a strongly hooked, unnotched upper jaw, and a short nonprojecting snout. Triturating surfaces of the jaws are narrow and ridgeless. This species is unique in having the orbit-nasal foramen posteriorly situated at the level of the primitive caroticum foramen, a broad triangular ethmoidalis fissure, and the forward extension of the epipterygoid to the level of the anterior border of the cranial cavity (McDowell, 1964). Posterior head skin is divided into large scales; the head is brown with dark vermiculations. One or two light spots may occur between the orbits and tympanum, and, contrary to some descriptions, these spots may elongate into black-bordered stripes. Limbs are gray to dark brown or black. Anterior surfaces of the forelegs are covered with large scales and the hindlegs are somewhat club shaped. The toes are only partially webbed. The tail is moderate in length, and pointed tubercles arise at its base and on the adjoining thighs.
The karyotype is 2n = 52; 28 macrochromosomes (18 metacentric or submetacentric, 10 telocentric or subtelocentric) and 24 microchromosomes (Bickham and Carr, 1983; Carr and Bickham, 1986).
Males have longer, thicker tails than do females.
Pyxidea is found in Guangdong, Guangxi, and Hunan Provinces, and on Hainan Island, China, and from Vietnam westward to Myanmar. There is also a record from Assam (Choudhury, 1993b).
Pyxidea mouhotii is a terrestrial species which seldom enters water. Nutphand (1979) commented that the only time it becomes wet is when it rains or from the morning dew. It is apparently a forest dweller, and Pope (1935) reported it inhabits mountainous terrain on Hainan.
During courtship males bite females on the neck (Das, 1991). Captives have oviposited from June to September (Boonman, 1994; Das, 1995). Das (1995) reported clutches contain 1-5 brittle-shelled eggs (40-56 x 25-27 mm). Incubation at 28°C takes 97-108 days (Weser, 1989; Boonman, 1994). Hatchlings are 35.0-39.2 mm and have a dark brown plastron with a brightly orange rim (Ewert, 1979; Das, 1991; Boonman, 1994).
In the wild, Pyxidea mouhotii has been reported to prefer plant foods, but captives are omnivorous (Das, 1995) to even predominantly carnivorous (Boonman, 1994). Sachsse (1973) thought Pyxidea mouhotii similar in habits to the North American Terrapene.
Based on similarities with Cuora galbinifrons serrata, Fritz and Obst (1997) speculated that Pyxidea mouhotii may eventually be considered a highly specialized form of Cuora.
IUCN Red List Status (1996)