Phrynops williamsi
Scientific classification edit
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Testudines
Suborder: Pleurodira
Family: Chelidae
Genus: Phrynops
P. williamsi
Binomial name
Phrynops williamsi
Rhodin & Mittermeier, 1983[2][3][4]

Phrynops williamsi, also known commonly as Williams' side-necked turtle, Williams' South American sideneck turtle, William's [sic] South American side-necked turtle, William's [sic] toadhead turtle, and Williams' toadhead turtle, is a species of turtle in the family Chelidae. The species is endemic to South America.


The specific name, williamsi, is in honor of American herpetologist Ernest E. Williams.[5]

Geographic range

P. williamsi is found in southeastern Brazil, Uruguay, and Argentina.[6]


The preferred natural habitat of P. williamsi is freshwater wetlands, at altitudes of 80–1,000 m (260–3,280 ft).[1]


  1. ^ a b Rhodin, A.G.J.; Bressan, R.F.; Buskirk, J.R.; Cabrera, M.R.; Carreira, S.; Estrades, A.; Mittermeier, R.A.; Vinke, S.; Vinke, T. (2018). "Phrynops williamsi". IUCN Red List of Threatened Species. 2018: e.T172024A1339018. doi:10.2305/IUCN.UK.2018-2.RLTS.T172024A1339018.en. Retrieved 18 November 2021.
  2. ^ Rhodin, Anders G.J., and Mittermeier, Russell A. (1983). "Description of Phrynops williamsi, a new species of chelid turtle of the South American P. geoffroanus complex". pp. 58-73. In: Rhodin, A.G.J., and Miyata, K. (Editors) (1983). Advances in Herpetology and Evolutionary Biology. Essays in Honor of Ernest E. Williams. Cambridge, Massachusetts: Museum of Comparative Zoology.
  3. ^ Fritz, Uwe; Peter Havaš (2007). "Checklist of Chelonians of the World" (PDF). Vertebrate Zoology. 57 (2): 341–342. ISSN 1864-5755. Archived from the original (PDF) on 2010-12-17. Retrieved 29 May 2012.
  4. ^ van Dijk, Peter Paul, John B. Iverson, H. Bradley Shaffer, Roger Bour, and Anders G.J. Rhodin (2012). "Turtles of the World, 2012 Update: Annotated Checklist of Taxonomy, Synonymy, Distribution, and Conservation Status". Chelonian Research Monographs No. 5, pp. 000.243–000.328.
  5. ^ Beolens, Bo, Michael Watkins, and Michael Grayson (2011). The Eponym Dictionary of Reptiles. Baltimore, Maryland: Johns Hopkins University Press. xiii + 296 pp. ISBN 978-1-4214-0135-5. (Phrynops williamsi, p. 286).
  6. ^ Phrynops williamsi. The Reptile Database.

Further reading