Cyclotosaurus cf. posthumus, Fraas, 1913

Nonsrirach, Thanit, Manitkoon, Sita & Lauprasert, Komsorn, 2021, First occurrence of brachyopid temnospondyls in Southeast Asia and review of the Mesozoic amphibians from Thailand, Fossil Record 24 (1), pp. 33-47 : 35

Cyclotosaurus cf. posthumus

Reference material

D.M. R. no. Ch.D 001 ( Fig. 2a–c ); a posterior part of a skull ( Ingavat and Janvier, 1981).

Formation/age

Huai Hin Lat Formation (Carnian–Norian).

Locality and sediment

The specimen was discovered in 1981 at an outcrop near the Chulabhorn Dam, Khon San District , Chaiyaphum Province. The fossil assemblage layer consists of a grey to red conglomerate .

Description

D.M. R. no. Ch.D 001 is a posterior part of a comparatively large skull (approximately 20 cm wide and 11 cm long), but the lateral part of the right side is missing. However, a pair of otic notches and a pineal foramen are preserved. The pattern of the ornamentation and the shallow interotic embayment of this skull allow an assignment to Cyclotosaurus ( Fraas, 1913; Ingavat and Janvier, 1981; Damiani, 2001) and are similar to those of the holotype of Cyclotosaurus posthumus Fraas, 1913 from the Upper Middle Keuper, Bavaria ( Germany).

Figures

Figure 2. Triassic amphibian remains from Thailand. A replica skull of Cyclotosaurus cf. posthumus (D.M.R. Ch.D 001) in dorsal (a), palatal (b), and posterior views (c). A reconstruction of Thai Cyclotosauridae (d). A dermal bone of Plagiosauroidea indet. (TF 1453) in ventral (e) and dorsal (f) views. A reconstruction of Thai Plagiosauroidea (g). Reconstruction images (d, g) are not to scale (drawn by Sita Manitkoon).