Phrynops hilarii, also commonly known as Hilaire’s side-necked turtle and Hilaire's toadhead turtle, is a species of freshwater turtle in the family Chelidae. The species is endemic to South America.
The specific name, hilarii, is in honor of French zoologist Isidore Geoffroy Saint-Hilaire.[1]
P. hilarii is found in southern Brazil (Santa Catarina and Rio Grande do Sul), southward and westward into Uruguay and Argentina, and possibly also in Paraguay and Bolivia.[2]
P. hilarii inhabits streams, lakes, and swamps with abundant aquatic vegetation and soft bottoms.
P. hilarii has an oval, flattened carapace, with a maximum straight-line length of approximately, weighing approximately . The carapace is usually dark brown, olive, or gray, with a yellow border. The head is large and flat, gray to olive above, with a pointed snout and two bicolored chin barbels. There is a black band on each side of the head, which comes out of the muzzle and passes over the eyes, going up to the neck. [3] [4]
An omnivorous species, P. hilarii mainly feeds on arthropods, with a preference for copepods, ostracods, and hemipterans.[5] It feeds also on fishes, reptiles, birds, small mammals, and carrion. It is oviparous.[2] This turtle can live for up to 37 years.[6]
Females lay eggs twice a year, one clutch between February and May and the other between September and December. They lay from 9 to 14 eggs, with a maximum of 32 eggs and an incubation period of approximately 150 days.