 "Aenigmaspina" was collected from Pant-y-ffynnon in South Wales, a quarry of Carboniferous limestone that contains fissures filled with Triassic-Early Jurassic aged sediment, from which "Aenigmaspina" and other Triassic-aged reptiles are known from.The exact age of the fissures is uncertain, but a latest Triassic Rhaetian age has been suggested based on biostratigraphy between the Pant-y-ffynnon fissures and other similar sites.The specimens were collected by palaeontologists Kenneth Kermack and Pamela Robinson of University College London between 1951–1952, along with four other species of reptile, and were first presented at a talk in 1953 and later written on briefly in 1956 where the specimen was informally nicknamed 'Edgar'.The specimen would eventually be fully described and formally named as part of a thesis by Erin Patrick and published in 2019.