Holotype of Retzneiosoma jaseneki Kroh, 2005 (NHMW 2003z0071/0002) from the Badenian (= Middle Miocene) of Retznei, Austria Aboral view showing imbricate plates, “membranous” gaps, and aboral tuberculation (A). Notice that large parts of the aboral surface are missing exposing the lantern and the inside of the oral surface (B; showing ambulacral plating). Kroh, A. 2005. Catalogus Fossilium Austriae. Band 2. Echinoidea neogenica, pp. lvi+210. Österreichische Akademie der Wissenschaften; Wien.