South-American Snake-headed Turtle

H. tectifera can reach up to 28 centimeters (11 inches) in straight carapace length. Its carapace is strongly keeled, and it can also be distinguished by black and yellowish markings along its head and neck. Generally, the females are larger than the males which often have larger tails.

The Argentine snake-necked turtle lives in slow-moving ponds, rivers, streams, and marshes, preferably with aquatic vegetation. In coastal areas, it will enter brackish water, and it may hibernate in colder areas of its distribution. It is carnivorous and eats snails, aquatic insects, fish, and amphibians. It attacks its prey with a combination of matamata-like vacuum suction and the stabbing neck motions of other snake-necked turtles. Courtship and mating has not been extensively observed in this species, although it is known that nesting occurs in the spring at the riverbanks. The eggs are 34 mm × 22 mm (1.34 in × 0.87 in), white, and brittle-shelled. Hatchlings have a straight carapace length of about 34 mm (1.3 in), and have a carapace which is more wrinkled than that of an adult.