Ankyramorpha ("anchor forms") is an extinct clade of procolophonomorph parareptiles which lived between the early Cisuralian epoch (middle Sakmarian stage) and the latest Triassic period (latest Rhaetian stage) of Africa, Antarctica, Asia, Australia, Europe, North America and South America.
[3][4][5] A similar name, Hallucicrania, was provided in an earlier 1995 study by Michael S. Y. Lee, who defined it as the node-based taxon formed by the most recent common ancestor of lanthanosuchids and "pareiasauroids" (pareiasaurs + Sclerosaurus), and all its descendants.
[6] Nevertheless, purely considering the taxa encompassed by their definitions, Hallucicrania and Ankyramorpha refer to an identical grouping.
The following cladogram is simplified after the phylogenetic analysis of MacDougall and Reisz (2014) and shows the placement of Ankyramorpha within Parareptilia.
[5] Mesosaurus Millerosauria Australothyris smithi Feeserpeton oklahomensis Colobomycter pholeter Delorhynchus cifellii Acleistorhinus pteroticus Lanthanosuchus watsoni Microleter mckinzieorum Belebey chengi Eudibamus cursoris Nycteroleteridae Pareiasauria Abyssomedon williamsi Nyctiphruretus acudens Owenettidae Procolophonidae