Mauremys mutica

(Cantor, 1842)
Asian yellow pond turtle

This is a medium-sized (to 19.5 cm) semi-aquatic batagurine turtle with a broad yellow stripe extending backward from the orbit over the tympanum to the neck. Its oval carapace is slightly wider behind the center, contains a low medial keel and two rather poorly developed lateral keels (which are more prominent in juveniles), slightly upturned lateral marginals, and slightly flared and serrated posterior marginals. Vertebral 1 is wider anteriorly than posteriorly. The carapace ranges in color from grayish brown to brown and the seams are usually dark. The plastron is large, slightly upturned anteriorly, and notched posteriorly. The bridge is about as wide as the length of the plastral hindlobe. The plastral formula is: fem ³ abd > pect > hum > an > gul. The plastron is yellow to orange with a large black blotch toward the outside of each scute; the bridge is similarly colored and has two large dark blotches. Head and neck are dorsally gray to olive, and always contain the striped pattern described above. Also, this stripe has its dorsal border darkly outlined. A second yellow stripe may extend diagonally downward and backward from the lower edge of the orbit or the corner of the mouth to below the tympanum. There is a dorsomedial yellow stripe on the neck. Chin and lower neck are usually yellow, but some individuals may have dark mottles. The snout is conical and slightly projecting, and the upper jaw is medially notched. The triturating surface of the upper jaw is narrow and lacks a ridge or serrations. Limbs and tail are gray to olive above, but yellow ventrally.
Diploid chromosomes total 52; 20 metacentric and submetacentric, 10 subtelocentric, and 22 acrocentric and telocentric (Stock, 1972; Killebrew, 1977a; Bickham and Carr, 1983).
The males have slightly concave plastra and longer, thicker tails with the vent beyond the margin of the carapace.

Mauremys mutica lives in northern Vietnam, southern China, and on Hainan, Taiwan, and Japan.

Geographic Variation
Two subspecies are recognized. The Asian yellow pond turtle Mauremys mutica mutica (Cantor, 1842) ranges from Vietnam, southern China, Hainan Island and Taiwan, to Japan (where it has been introduced). It reaches a maximum carapace length of at least 19.5 cm, with a dark brown or blackish gray, slightly domed carapace, coalescing dark pigment on the plastron, a dark brown or gray-black head, and a prominent light stripe between the orbit and the neck. The Ryukyu yellow pond turtle M. m. kami Yasukawa, Ota, and Iverson, 1996 is found only on the western Ryukyu Islands. It reaches a maximum carapace length of 18.9 cm, with a yellowish or grayish tan to light brown, relatively depressed carapace, a plastral pattern of separated large dark blotches, a light gray, tan or light brown head, and no prominent light stripe between the orbit and the neck.
Iverson and McCord (1994) report considerable variation in head and skin coloration within the nominate subspecies; populations from the northeastern part of the range have a light grayish-yellow head and skin and a very faint temporal head stripe, whereas the head and skin of southwestern populations is much darker and the head stripe very bold and brightly yellow, bordered with thin black lines.

Mauremys mutica inhabits low-altitude water bodies with slow currents such as ponds, marshes, swamps, and creeks.

Natural History
According to Hofstra (1995), mating behavior in M. mutica is very straightforward; the male simply approaches the female and tries to mount. Clutches comprise of 1-2 brittle-shelled eggs (38 x 21 mm); these hatch in an average of 94.2 days when incubated at 25-25.5°C and in 64.7 days at 29.5-30°C. Hatchlings are 25-33 mm and weigh 5-8 g (Ewert, 1979; Hofstra, 1995).
Mauremys mutica is fond of basking, and captives do well on a fish diet.

IUCN Red List Status (1996)
Not listed.