The holotype material, UNIPAMPA 653, was collected from an exposure in the Sanga do Cabral Formation in Southern Brazil, informally known as Bica São Tomé, located in the Paraná Basin.
The locality is composed of five outcrops, with UNIPAMPA 653 being found roughly 5 metres (16 ft) above the base of outcrop 5, in a layer rich in calcareous concretions.
 The specimen was collected by a team from the Paleobiology Laboratory of the Universidade Federal do Pampa (Unipampa) at the beginning of 2015, and later described in a study co-authored by Dr. Felipe L. Pinheiro and others and published in Scientific Reports (Nature Publishing Group) in early 2016.

The skull was noted to be exceptionally well preserved, as many other fossils from the Sanga do Cabral Formation are typically more fragmented and poorly preserved, having been reworked from slightly older sediments amongst layers of conglomerates.
In addition to its unusual completeness, the skull was also CT scanned to reveal further details of the fossil that were still hidden by the surrounding matrix, particularly areas of the left side of the skull, palatal and occipital regions.

The genus name Teyujagua is derived from Teyú Yaguá, one of seven legendary monsters that are a part of Guaraní mythology.
The Guaraní people occupied a large territory in central east South America, including an area of Southern Brazil where the type locality of Teyujagua is located.
Teyú Yaguá is often depicted as a huge lizard with either seven or one large dog-head.
Pinheiro et al.
named it for Teyú Yaguá with the intended literal translation of "fierce lizard", although "dog lizard" has been offered as the correct literal Guaraní translation.
The specific name is derived from Greek paradoxa ("paradoxical", "unexpected"), referring to its unusual combination of ancestral and derived archosauriform characteristics.
The holotype material, UNIPAMPA 653, was collected from an exposure in the Sanga do Cabral Formation in Southern Brazil, informally known as Bica São Tomé, located in the Paraná Basin. The locality is composed of five outcrops, with UNIPAMPA 653 being found roughly 5 metres (16 ft) above the base of outcrop 5, in a layer rich in calcareous concretions.  The specimen was collected by a team from the Paleobiology Laboratory of the Universidade Federal do Pampa (Unipampa) at the beginning of 2015, and later described in a study co-authored by Dr. Felipe L. Pinheiro and others and published in Scientific Reports (Nature Publishing Group) in early 2016.
The skull was noted to be exceptionally well preserved, as many other fossils from the Sanga do Cabral Formation are typically more fragmented and poorly preserved, having been reworked from slightly older sediments amongst layers of conglomerates. In addition to its unusual completeness, the skull was also CT scanned to reveal further details of the fossil that were still hidden by the surrounding matrix, particularly areas of the left side of the skull, palatal and occipital regions.
The genus name Teyujagua is derived from Teyú Yaguá, one of seven legendary monsters that are a part of Guaraní mythology. The Guaraní people occupied a large territory in central east South America, including an area of Southern Brazil where the type locality of Teyujagua is located. Teyú Yaguá is often depicted as a huge lizard with either seven or one large dog-head. Pinheiro et al. named it for Teyú Yaguá with the intended literal translation of "fierce lizard", although "dog lizard" has been offered as the correct literal Guaraní translation. The specific name is derived from Greek paradoxa ("paradoxical", "unexpected"), referring to its unusual combination of ancestral and derived archosauriform characteristics.
Teyujagua