NATURAL HISTORY · CATALOGUE RECORD
William’s South-American Side-necked Turtle
Phrynops williamsi Rhodin & Mittermeier, 1983
Source-backed taxonomic record
Accepted species in Catalogue of Life’s 11 September 2026 base release. This preserves the source classification and available supporting data; it is not a completed species monograph.
William's toadhead turtle at Iguazu Falls, Argentina
Peterwchen · CC BY-SA 4.0 · Image sourceProvider-generated thumbnail requested at 800 pixels; no local editing Local WebP display rendition; resized without cropping.
Open encyclopedia reference
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.
Wikipedia contributors, Phrynops williamsi; see linked history · CC BY-SA 4.0 . Plain-text lead excerpt, at most 180 words; no infobox or later sections Retrieved 2026-10-05T13:19:01.207661+00:00. This reference remains separate from the taxonomic record.
Identity & source status
- Scientific name
- Phrynops williamsi Rhodin & Mittermeier, 1983
- Name authority
- Rhodin & Mittermeier, 1983
- Common name
- William’s South-American Side-necked Turtle
- Rank
- species
- Accepted status
- accepted
- Kingdom
- Animalia
- Phylum
- Chordata
- Class
- Reptilia
- Order
- Testudines
- Family
- Chelidae
- Genus
- Phrynops
- Extinction status
- Not supplied by this source
Classification family tree
Nested taxonomic groups from the source. This is not a direct-ancestor chain, a dated evolutionary tree or a phylogenetic reconstruction.
- domainEukaryota (Chatton, 1925) Whittaker & Margulis, 1978
- kingdomAnimalia
- phylumChordata
- subphylumVertebrata
- infraphylumGnathostomata
- parvphylumOsteichthyes
- megaclassTetrapoda
- classReptilia Laurenti, 1768
- orderTestudines Batsch, 1788
- suborderPleurodira Cope, 1864
- superfamilyCheloidea Gray, 1825
- familyChelidae
- genusPhrynops
- speciesPhrynops williamsi Rhodin & Mittermeier, 1983
Close classified relatives
These entries share the source’s genus, Phrynops. They are not necessarily the closest relatives established by molecular evidence.
| Species | Classification | Source status |
|---|---|---|
| Hilaire’s Side-necked TurtlePhrynops hilarii (Duméril & Bibron, 1835) | ChelidaeChordata | Accepted speciesExtinction status not supplied |
| Geoffroy’s Side-necked TurtlePhrynops geoffroanus (Schweigger, 1812) | ChelidaeChordata | Accepted speciesExtinction status not supplied |
| Cotinga River Toadhead TurtlePhrynops tuberosus (Peters, 1870) | ChelidaeChordata | Accepted speciesExtinction status not supplied |
Documented distribution
Source distribution statements, not a complete range map. A listed locality is not necessarily a place of origin.
Source literature & publication evidence
References attached to this source record, including nomenclatural citations where supplied. This is a selected bibliography; abbreviated citations remain in the source’s form.
- https://reptile-database.reptarium.cz/species?genus=Phrynops&species=williamsi Source fields: Taxon.tsv dwc:namePublishedIn, Taxon.tsv dcterms:references
Origins, evidence & remaining research
Name authority and publication references document nomenclature where the source supplies it. They do not establish evolutionary origins or the earliest fossil occurrence.
Specimen-level evidence, morphology, ecological research, phylogenetic studies, a comprehensive bibliography and a located literary passage have not yet been compiled for this record.
Dataset citation & attribution
This exact taxon in ChecklistBank · Catalogue of Life 2026-09-11
Catalogue of Life 2026-09-11; dataset 316321; doi:10.48580/dgz5n. https://creativecommons.org/licenses/by/4.0/ . Retrieved 5 October 2026.
Stable key: col:4GWP6. Classification follows source parent identifiers. English common names may vary by region.