(Gray, 1831, in Gray, 1830-1835)
Red-crowned roofed turtle
The elliptical carapace (to 56 cm) is widest behind the middle, slightly depressed, and smooth to slightly serrated along the posterior rim. A medial keel is present with posterior projections on vertebrals 2-3; the projection on vertebral 3 is more prominent in juveniles and becomes lower with age. Vertebrals 1, 3, and 5 are broader than long, the 2nd is about as long as broad, and the 4th is much longer than broad. The carapace varies from brown to olive in color. The plastron is long and narrow; both the anterior and posterior lobes are shorter than the broad bridge. A posterior anal notch is not always present. The humero-pectoral seam joins the plastral midseam at an obtuse angle. The plastral formula is: abd > fem > hum > pect > an > gul. On the bridge, the inguinal scute is much larger than the axillary. Both plastron and bridge are immaculate yellow. The head is moderate in size with a short, slightly upturned, projecting snout. Its upper jaw contains a shallow medial notch bordered on each side by a toothlike projection. Kachuga kachuga is the only Kachuga to have two (rather than one) denticulated ridges on the palate (a trait shared with Batagur baska). Skin on the back of the head is subdivided into scales. The male's head is red dorsally and bluish gray on the sides; the female's head is olive blue. In males, the sides of head are decked with two yellow stripes: a postocular stripe extending from the eye to the tympanum, and a second just below, beginning at the yellow snout and mandibles and extending posterior to the neck. A pair of red or yellow spots occur on the throat, and the jaws may be brown. The neck is olive brown in females, but contains a series of seven red or red-brown longitudinal stripes in the male. Red pigmentation in males is most brilliant during the breeding season, fading and disappearing afterward. Limbs are brown to olive with transverse scales on the anterior surface of the forelegs.
In addition to the sexual dichromatism, several other features distinguish adult males from adult females. Females are larger and have short tails. The smaller males have long, thick tails.
Kachuga kachuga ranges from southern Nepal southward through Bangladesh, to adjacent northeastern India. It resides primarily in the watershed of the Ganges River, but has also been reported from the Godavari and Kristna river basins in India.
Adults are inhabitants of deep, flowing rivers.
Females nest in March and April (Chaudhuri, 1912; Moll, 1986; Rao and Singh, 1987; Das, 1991, 1995). Nest cavities are typically 42-54 cm deep (Das, 1991). Clutches contain 15-30 white, oval, elongated (64-75.4 x 37.6-45.6 mm) eggs. Hatchlings emerge in May or June (Chaudhuri, 1912) at a carapace length of about 60 mm (Moll, 1986).
Das (1991) reported that captives are entirely herbivorous.
IUCN Red List Status (1996)