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 Subfamily UMBONEINAE Lyssenko & Aliev, 1987 ( Fig. 3G ) Umboneidae Lyssenko & Aliev, 1987: 117 TYPE GENUS. — Umbonea Pchelintsev, 1965 ( 1965: 85 ) . TYPE SPECIES. — Nerinea dilatata d’Orbigny, 1852 (1852: 146) . SUBFAMILY CHARACTERS . — Shells with hollow columella; whorls almost triangular in outline, siphonal notch located on acute extension of aperture. The columellar, parietal and palatal plaits are small. The umbilicus may be covered by a thin lamella. REMARKS This group is assigned to the Ptygmatididae because of the typical siphonal portion which protrudes at about 60° into the umbilicus. It has been named Diozoptyxisidae by Pchelintsev (1965) . Diozoptyxis Cossmann, 1907 belongs, in fact, to the Campaniloidea (see Kollmann & Peza 1997 a; Kollmann 2005 ). Ptygmatididae species originally assigned to this family are allocated to the Umboneinae Lyssenko & Aliev, 1987 .