Microsphenodon bonapartei (Chambi-Trowell et al. 2021; Late Triassic) was a contemporary and variation of Clevosaurus brasiliensis with distinct skull proportions.

Clevosaurus brasiliensis (Bonaparte and Sues 2006, Carnian, Late Triassic ~200 mya) is a second species. Note the elongate posterior mandible, short nasals and constricted rostrum. This genus is known world wide.

Clevosaurus hudsoni (Swinton 1939) Carnian, Late Triassic ~200 mya, was a derived rhynchocephalian with teeth fused to one another and to the jaw bones. Derived from a sister to Brachyrhinodon.

The premaxilla rose posterior to the nares, which are elongated. The frontals are wider with posterior processes. The jugal does not contact the squamosal. The ilium is taller than long.

Sphenotitan leyesi (Martinez et al. 2014) Late Triassic, Argentina had an elaborate maxilla with large grooves. This specimen is known from a partial skull in 3D. This was an early herbivore.

Bonaparte JF and Sues HD 2006. A new species of Clevosaurus (lepidosauria: rhynchocephalia) from the upper Triassic of Rio Grande do Sul, Brazil. Palaeontology. 49 (1): 917–923.

Chambi-Trowell, SAV et al. 9 co-authors 2021. The diversity of Triassic South American sphenodontians: a new basal form, clevosaurs, and a revision of rhynchocephalian phylogeny. Journal of Systematic Palaeontology. 19(11): 787–820.

Martinez et al. 2014. A new sphenodontian (Lepidosauria: Rhynchocephalia) from the Late Triassic of Argentina and the early origin of the herbivore opisthodontians. Proceedings of the Royal Society

Swinton WE 1939. A new Triassic rhynchocephalian from Gloucestershire. Annals and Magazine of Natural History 11(4):591-594.

wiki/Clevosaurus