Chelodina novaeguineae

Boulenger, 1888b
New Guinea snake-necked turtle

The oval carapace (to 30 cm) is broadest behind the center, and has a smooth posterior rim, depressed vertebrals, and a pronounced medial groove on the 2nd to 4th vertebrals. Vertebrals are broader than long in adults; the 1st is the largest and is flared anteriorly, the 4th is the smallest, and the 5th is flared posteriorly. Although neural bones are usually absent, Rhodin and Mittermeier (1977) found 5 of 20 New Guinea specimens had one to four scattered neurals. Surfaces of the carapacial scutes, at least in young individuals, are covered with rugose radiations. Lateral marginals are not upturned as in C. longicollis, and those over the tail are at best only slightly raised. The carapace is chestnut to dark brown. The plastron is large, covering most of the carapacial opening, and is deeply notched posteriorly. Its forelobe is broad, but does not reach the marginals; the hindlobe tapers toward the rear. The plastral formula is: intergul > an > fem > hum > pect > gul, with the intergular at least twice as long as the interpectoral seam. The bridge is moderate in size. Plastron, bridge, and undersides of the marginals vary from cream to yellow; their seams may be narrowly bordered in black. The head is broad and flat with a slightly protruding snout and an unnotched upper jaw. The jaws are wide and the maxillae compose more of the palate than in other Chelodina. The neck is comparatively short and thin, only about 55-60% of the carapace length, and its dorsal surface is covered with large, rounded tubercles. Head and neck are olive brown to brown above and cream to yellow below. Limbs are olive to brown. Each foreleg has a series of five enlarged transverse scales on its anterior surface.
Males have longer tails than do females.

Chelodina novaeguineae is known from southwestern Papua New Guinea. In Australia, it occurs from coastal northeastern Queensland to the Daly Waters region of the Northern Territory.

Geographic Variation
Largely unknown; this species awaits further investigation. Hatchlings and small juveniles from the east coast of Queensland differ in color of skin, eyes, and shell (John Cann, pers. comm.). The Queensland form was named as Chelodina rankini by Wells and Wellington (1985), but without proper diagnosis; see taxonomic comment under Family Chelidae for an evaluation of this publication.

Chelodina novaeguineae lives in semipermanent, seasonally ephemeral swamps (Kennett et al., 1992). The turtle either aestivates or migrates to a more permanent waterbody when the swamps dry up.

Natural History
Engberg (1978), Cann (1978), and Feldman (1979) have reported their observations on courtship and mating in Chelodina novaeguineae. The male swims around the female and approaches from the rear. He rubs his chin over her carapace, progressing forward from her posterior marginals. By the time his chin touches the base of her neck, his forefeet are able to reach her carapace. He climbs onto her back and places his hind feet over hers and continues to caress her neck with his chin. She then bobs her head in response. Intromission soon follows. Feldman's (1979) male placed his feet at the base of his tail as if to aid in extruding his penis. Cann (1978) reported that once intromission occurred, the male relaxed the grip of his forefeet and drifted slowly upward to an almost vertical position (apparently somewhat similar to that of male Terrapene carolina).
Nesting takes place during the dry season. Cann (1978) collected females in West New Guinea that had clutches of 17 to 21 eggs in September. He found several emerging from eggs after a 9-week incubation period. Goode (1967) reported that Australian C. novaeguineae lay clutches of 9 to 12 eggs. Eggs are elongated, 29.0-31.4 x 20.0-21.8 mm; hatchlings average 31.3 mm in carapace length (Kennett et al., 1992).
Natural foods include snails, prawns, insects, amphibians, and probably small fish. Various aquatic plants are also consumed.
This species emits a rather pungent defensive odor from its scent glands when first captured, but soon ceases this objectionable habit in captivity.

IUCN Red List Status (1996)
Not listed.