Twist Necked Turtle15/04/2021
The Twist Necked Turtle (Platemys platycephala) also known as the flat-headed turtle, is distributed widely across northern South America. Twistoofnecked turtles have extremely flat shells that help them hide from predators under rocks and debris. When threatened, this turtle withdraws by twisting its head into its shell. Platemys platycephala is the only species of the genus Platemys and occurs in northern and central South America. Platemys platycephala means «flat turtle, flat-head» and accurately describes the structure of the head and shell. This species inhabits shallow creek beds and frequently forages on the floor of the Amazon rainforest for insects, amphibians, and molluscs. Camouflage, head and body shape, and advanced sexual anatomy allow this species of turtle to effectively populate much of South America. Mating occurs during rainy months (March – December) and egg deposit occurs during dry months (January – March). Males have been known to behave aggressively towards females during copulation by squirting water from nostrils and biting.
Platemys platycephala is a medium-sized turtle ranging from 14 – 18 cm in shell length. Females are slightly smaller on average, with shorter tails. The carapace (top portion of the shell) is elliptical and flattened with two raised portions (keels) forming a trough (depression). The carapace is orange to yellow-brown and black in various amounts depending on subspecies. The plastron (lower portion of the shell) is dark brown or black in colour while the bridge (side portion of the shell) is yellow with a black bar across. The consistency of these bars also depends on subspecies. Face and neck patterns consist of orange or yellow-brown dorsal stripes and black ventral and lateral stripes. The head is small, triangular, smooth, and undivided. The neck has some conical tubercles- rounded projections and scales that protect against predator attack. Platemys platycephala is a member of the Pleurodira – a suborder of turtles. These turtles withdraw their heads into their shells by bending their necks sideways instead of the straight back like Cryptodira. The snout projects slightly and the irises are brown. Black limbs contain large anterior scales, while the tail is short and black. Intermediate webbing exists on both anterior and posterior limbs because this turtle moves in the water and on land.
The Twist Necked Turtle inhabits a large area throughout northern and central South America, from the southern Orinoco drainage in Venezuela to the Amazon basin. However, Platemys platycephala does not inhabit large rivers but instead is found in shallow creeks and on forest floors.
The colouration and shape of the carapace, head, and feet help conceal this species of turtle from Amazon predator species. Naturally, twist-necked individuals prefer amphibian eggs and consume various insects, molluscs (snails and slugs), amphibians, and some plant life through terrestrial and aquatic foraging. In captivity, specimens can flourish on reptile food, vegetables, insects, worms, and even fish. Platemys platycephala is likely to be found in shallow pools and can inhabit dry areas for long periods of time.
The young or hatchlings typically resemble parents except for brighter colouration. Twist-necked hatchlings measure around 4 – 6 cm in carapace length and about 20 g or 0.04 lbs. Mating typically occurs during the rainy season of the Amazon rainforest (late March to early December). Males follow females, mount from behind, then proceed to rub their chin barbels (fleshy filament) against the top of females’ heads. The coupling has been observed on land and in water, and usually occurs late in the afternoon or at night. Oviposition occurs during the dry season (late December to early March) when the female deposits a large, oval egg (around 5 cm long and 2.5 cm wide). Shallow indentations are made to deposit eggs, and then they are lightly covered by sand and/or leaf litter.