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.
Etymology The specific name, hilarii, is in honor of French zoologist Isidore Geoffroy Saint-Hilaire.Beolens, Bo; Watkins, Michael; Grayson, Michael (2011). The Eponym Dictionary of Reptiles. Baltimore: Johns Hopkins University Press. xiii + 296 pp. . (Phrynops hilarii, p. 123).
Geographic range Phrynops 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. www.reptile-database.org.
Habitat Phrynops hilarii inhabits streams, lakes, and swamps with abundant aquatic vegetation and soft bottoms.
Description
Phrynops 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. Cabrera, Mario R.; Colantonio, Sonia E. (2001). "Ontogenetic variation of plastral spotting pattern in Phrynops hilarii (Testudines, Chelidae)" Iheringia, Sér. Zool., Porto Alegre (91): 115–122."Phrynops hilarii ". Turtles of the World
Biology
An omnivorous species, P. hilarii mainly feeds on arthropods, with a preference for copepods, ostracods, and hemipterans.Alcalde, Leandro; Derocco, Natacha Nara; Rosset, Sergio Daniel (2010). "Feeding in Syntopy: Diet of Hydromedusa tectifera and Phrynops hilarii (Chelidae)" Chelonian Conservation and Biology 9 (1): 3–344. It feeds also on fishes, reptiles, birds, small mammals, and carrion. It is oviparous. This turtle can live for up to 37 years."Phrynops hilarii ". AnAge: The Animal Ageing and Longevity Database
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.
References
Further reading Boulenger, George Albert (1889). Catalogue of the Chelonians, Rhynchocephalians, and Crocodiles in the British Museum (Natural History). New Edition. London: Trustees of the British Museum (Natural History). (Taylor and Francis, printers). x + 311 pp. + Plates I-III. (Hydraspis hilarii: p. 220, figure 59, three views of skull; p. 221, figure 60, carapace and plastron; p. 222, species description).