Revision of the brachiopod Cyrtina rigauxi Maillieux, 1909 and description of a new ambocoeliid genus (Dionacoelia n. gen.) from the Frasnain of southern Belgium. Bulletin de l'Institut Royal des Sciences Naturelles de Belgique Sciences de la Terre, 75 2005: 53-66. 58 [Zoological Record Volume 141]