Class Gastropoda Cuvier, 1795
Family Rissoidae Gray, 1847
Genus Alvania Risso, 1826
Species Alvania punctura (Montagu, 1803)
Alvania punctura (Montagu, 1803)
Common in Tuscan Pliocene. Yellow sands.
Gastropoda Rissoidae Alvania Alvania punctura Pliocene
Original Description – Descrizione originale
(O.D.) T. with six very glossy, rounded volutions, rather taper in shape, and finely reticulated: colour transparent yellowish-with: aperture sub-orbicular. Length the tenth of an inch; breadth one third its length. We found this elegant species at whitsand bay in Cornwall, and in sand from Salcomb bay in Devonshire, but extremely rare; its beauty in only to be feen under a strong magnifier, as the work is extremely fine; by the aid of a microscope, it appears delicately punctured all over, and wrought with extremely fine decussated striae.
Conchiglia piccola, turrita, formata da sei giri convessi separati da suture profonde. Protoconca giri 2,5 terminanti con un esile labbro poco elevato. I giri sono ornati da numerose e irregolari file di minutissime papille così disposte: nelle tre-quattro file presso la sutura anteriore sono più numerose e appressate, le due-tre file seguenti sono formate da tratti di tre-quattro papille leggermente obliqui e distaccati, nelle file poste nella parte posteriore del giro le papille sono di dimensioni minori e più distanti. Teleoconca ornata da 25-30 esili costicelle assiali, separate da intervalli più ampi e da 5-6 cingoli spirali esili quanto le coste, alternati da solchi più ampi. Le coste ed i cingoli, incrociandosi, rendono la superficie elegantemente clathrata. Ultimo giro alto 3/5 dell’altezza totale con apertura circolare posteriormente ristretta. Labbro esterno sub varicoso internamente liscio. Sui giri intermedi di alcuni esemplari sono presenti una o due robuste varici (Chirli, 2006).
Small, turreted shell, of six convex whorls, separated by deep suture lines. Protoconch, 2.5 whorls, ending with a thin little lip, poorly high. On the embryonic whorls there are numerous and irregular rows of very small papillae, arranged in this way: three-four rows, near the anterior suture, where the papillae are more numerous and close; the following two-three rows where there are tracts of three-four slightly oblique and detached papillae; rows placed at the back of the whorl, where the papillae are smaller and more distant. Ornamentation of teleoconch consisting of 25-30 slender axial ribs, separated by wider intervals and 5-6 slender spiral cords, alternating with wider furrows. The ribs and the cords, crossing each other, make the surface elegantly clathrated. Last whorl 3/5 of the total height with a circular aperture, rear narrowed. Sub varicose external lip, internally smooth. On the intermediate whorls of some specimens, there are one or two strong varices.
Bibliographic references and some more common synonyms
1803 Turbo punctura – Montagu, p. 320, pl. 12, fig. 5
1827 Alvania minuta – Bonelli ms, n. 3045
1892 Alvania puncturata – Locard, p. 163
1845 Alvania insenghae – Calcara, p. 28, pl. 4, fig. 10
1864 Rissoa striatissima – Conti, p. 29
1895 Alvania (Arsenia) punctura v. exquisita – Sacco, p. 26, fig. 63
1895 Alvania (Arsenia) punctura v. tauroprecedens – Sacco, p. 27, fig. 64
2006 Alvania punctura – Chirli, p. 31, pl. 15, figs 5-14
2021 Alvania punctura – Chirli & Forli, p. 162, pls 128, 129, 130, figs B1-14, A1-19, A1-17
Stratigraphic distribution
Miocene – Bulgaria and Poland. Pliocene – Portugal and Spain, common in Italy. Pleistocene – Italy and Rhodes (Greece). Recent – Atlanto-mediterranean species, reported until the coasts of Norway and Barents Sea. It lives between mud and debris of the circalittoral zone.
References
Chirli C. (2006). Malacofauna Pliocenica Toscana – Caenogastropoda. Vol. 5, pp. 144, 46 plates.
Montagu G. (1803). Testacea Britannica or natural history of British shells, marine, land, and fresh-water, including the most minute: Systematically arranged and embellished with figures. J. White, London, Vol. 1, xxxvii + 291 pp;; Vol. 2, pp. 293–606, pl. 1-16., available online at http://www.biodiversitylibrary.org/item/78694
Acknowledgements
Si ringrazia l’amico Carlo Chirli (Tavarnelle, Firenze) per la concessione all’uso di alcuni suoi testi. See also Edizioni Danaus
