The extinct Nerineoidea and Acteonelloidea (Heterobranchia, Gastropoda): a palaeobiological approach Author Kollmann, Heinz A. text Geodiversitas 2014 2014-09-26 36 3 349 383 http://dx.doi.org/10.5252/g2014n3a2 journal article 6397 10.5252/g2014n3a2 5dd903f5-b398-4a17-83e5-364766291411 1638-9395 4538503 Family ITIERIIDAE Cossmann, 1896 ( Fig. 6 A-F) Itieriidae Cossmann, 1896: 16 . TYPE GENUS. — Itieria Matheron, 1842 (1842: 493) . TYPE SPECIES. — Itieria cabanetiana d’Orbigny, 1841 (1841: 318) . FAMILY CHARACTERS . — Shell oval to coniform, with high, narrow whorls. Spire short, irregularily coiled, depressed or convolute. Base umbilicate, with siphonal fasciole or short siphonal canal. Columella low, with one plait in Jurassic taxa, up to three in Cretaceous ones. Palatal wall with broad but low plait or pouch. REMARKS The whorls are high and narrow in cross section and reminiscent of the Acteonelloidea but possess a central cavity and a siphonal fasciole. In some cases only the internal mould of the cenrtral cavity is preserved ( Fig. 6C ). The Early Cretaceous Eotrochactaeon Akopjan, 1976 possesses a broad oviform shell with a short spire and 3 columellar plaits and is externally homologous with the Acteonelloidea genus Trochactaeon Meek, 1863 ( Fig. 6F ).A siphonal fasciole recognizable in axial sections of the columella distinguishes Eotrochactaeon from this genus (see Kollmann 1982 ; Sohl & Kollmann 1985 ).