Turbonilla

The generally slender, bluish-white to milk-white, semitranslucent shell is more or less elongated and has a cylindro-conic shape.

The apex is sinistral. The reversed, flattened or projecting protoconch consists of 1½ to 3 whorls that are oblique or tilted from transverse to the axis.

The teleoconch contains many planulate or more or less convex whorls. These are sometimes shouldered and are generally ornamented with less prominent longitudinal ribs ( = costulate).

The intercostal spaces are smooth or crossed bv more or less distinct, incised, sometimes raised, spiral lines. The spiral lines often also appear on the base of the shell, which varies from short, little rounded (the body whorl is subangulated at the periphery), to elongate and well-rounded.

The shape of the aperture varies from subquadrate with a straight columellar lip, to an elongate-ovate shape, well-rounded and produced below, with a curved columellar lip. The peritreme is generally discontinuous, rarely continuous.

The outer lip is always thin and entire. The inner lip is more or less thickened and reflected, often with a plication or fold that is not always visible externally.

The columella is vertical, not plicate. The columellar fold is single, varying in strength. The horny operculum is subspiral. The shell is usually smaller than in Pyramidella and larger than in Odostomia.

The animal has wide tentacles, an elongated, flattened mentum, usually bilobed in front. The foot is large and anteriorly auriculated.[4][5][6]

Species within the genus Turbonilla include:[1]

The following species were brought into synonymy:[1]

• Turbonilla abbreviata W. H. Turton, 1932
• Turbonilla admirabilis W. H. Turton, 1932
• Turbonilla becki W. H. Turton, 1932
• Turbonilla columna W. H. Turton, 1932
• Turbonilla distincta W. H. Turton, 1932
• Turbonilla erecta W. H. Turton, 1932
• Turbonilla intersecta W. H. Turton, 1932
• Turbonilla liratula W. H. Turton, 1932
• Turbonilla multistriata W. H. Turton, 1932
• Turbonilla retusa W. H. Turton, 1932
• Turbonilla perexilis W. H. Turton, 1932
• Turbonilla perminima W. H. Turton, 1932
• Turbonilla producta W. H. Turton, 1932
• Turbonilla rietensis W. H. Turton, 1932
• Turbonilla rufanensis W. H. Turton, 1932
• Turbonilla subcancellata W. H. Turton, 1932
• Turbonilla subconica W. H. Turton, 1932
• Turbonilla subglobosa W. H. Turton, 1932

• Aartsen, J.J. van, 1981. European Pyramidellidae: II. Turbonilla.— Boll, malac. 17: 61-88.
• Vaught, K.C. (1989). A classification of the living Mollusca. American Malacologists: Melbourne, FL (USA). ISBN 0-915826-22-4. XII, 195 pp.
• Howson, C.M.; Picton, B.E. (Ed.) (1997). The species directory of the marine fauna and flora of the British Isles and surrounding seas. Ulster Museum Publication, 276. The Ulster Museum: Belfast, UK. ISBN 0-948150-06-8. vi, 508 (+ cd-rom)
• Gofas, S.; Le Renard, J.; Bouchet, P. (2001). Mollusca, in: Costello, M.J. et al. (Ed.) (2001). European register of marine species: a check-list of the marine species in Europe and a bibliography of guides to their identification. Collection Patrimoines Naturels, 50: pp. 180–213
• Spencer, H.; Marshall. B. (2009). All Mollusca except Opisthobranchia. In: Gordon, D. (Ed.) (2009). New Zealand Inventory of Biodiversity. Volume One: Kingdom Animalia. 584 pp
• Frøydis Lygre, Jon Anders Kongsrud and Christoffer Schander, Four new species of Turbonilla (Gastropoda, Pyramidellimorpha, Turbonillidae) from the Gulf of Guinea, West Africa; African Invertebrates Vol. 52 (2) Pages 243–254 Pietermaritzburg December, 2011