original description(ofNymphaster oligoplax Sladen, 1893 †)Sladen, W.P. (1891). A Monograph on the British fossil Echinodermata from the Cretaceous Formations. Volume 2. The Asteroidea and Ophiuroidea. <em>Palaeontographical Society (Monograph).</em> Part 1: 1-28, pls. 1-8., available online athttps://biodiversitylibrary.org/page/12090462 page(s): 19 [details]