[4] The oldest, questionable, species is Cyclotosaurus papilio, known from a partial skull recovered from the Ladinian (Middle Triassic) age Upper Muschelkalk beds from Baden-Württemberg in Germany.

[8] A partial skull very similar to C. posthumus has been recovered from the Norian (Late Triassic) Huai Hin Lat Formation near Chulabhorn Dam in Northeastern Thailand.

[6] In 2016 a new species, C. buechneri, was described from the Late Triassic (middle Carnian) Stuttgart Formation of Bielefeld, the northernmost record in Germany.

[2] In 2019 a Cyclotosaurus humerus was reported from a Rhaetian aged bone bed within Bonenburg clay pit in eastern North Rhine-Westphalia, Germany.

[9] C. robustus C. buechneri C. mordax C. ebrachensis C. intermedius C. posthumus C. hemprichi See also alternative phylogenies from 2017[2] with the description of C. naraserluki.