Richardoestesia-like teeth have been found in many Late Cretaceous geological formations, including the Horseshoe Canyon Formation, the Scollard Formation, Hell Creek Formation, Ferris Formation, and the Lance Formation (dated to about 66 million years ago).
Similar teeth have been referred to this genus from as early as the Barremian age (Cedar Mountain Formation, 125 million years ago).

Because of the disparity in location and time of the many referred teeth, researchers have cast doubt on the idea that they all belong to the same genus or species, and the genus is best considered a form taxon.
A comparative study of the teeth published in 2013 demonstrated that both R. gilmorei and R. isosceles were only definitively present in the Dinosaur Park Formation, dated to between 76.5 and 75 million years ago.
R. isosceles was also present in the Aguja Formation, roughly the same age.
All other referred teeth most likely belong to different species, which have not been named due to the lack of body fossils for comparison.

Fossils of Richartoestesia have also been found in the Tremp Formation of northeastern Spain and possibly also the Lourinha Formation (Blasi 2 member) of Portugal, although this is unlikely since the Lourinha Formation dates to the Late Jurassic (152 Ma).
Richardoestesia-like teeth have been found in many Late Cretaceous geological formations, including the Horseshoe Canyon Formation, the Scollard Formation, Hell Creek Formation, Ferris Formation, and the Lance Formation (dated to about 66 million years ago). Similar teeth have been referred to this genus from as early as the Barremian age (Cedar Mountain Formation, 125 million years ago).
Because of the disparity in location and time of the many referred teeth, researchers have cast doubt on the idea that they all belong to the same genus or species, and the genus is best considered a form taxon. A comparative study of the teeth published in 2013 demonstrated that both R. gilmorei and R. isosceles were only definitively present in the Dinosaur Park Formation, dated to between 76.5 and 75 million years ago. R. isosceles was also present in the Aguja Formation, roughly the same age. All other referred teeth most likely belong to different species, which have not been named due to the lack of body fossils for comparison.
Fossils of Richartoestesia have also been found in the Tremp Formation of northeastern Spain and possibly also the Lourinha Formation (Blasi 2 member) of Portugal, although this is unlikely since the Lourinha Formation dates to the Late Jurassic (152 Ma).
Richardoestesia