Class Gastropoda Cuvier, 1795

Family Rissoidae Gray, 1847

Genus Alvania Risso, 1826

Species Alvania cancellata (da Costa, 1778)

 Alvania cancellata (da Costa, 1778)

Common species in Tuscan Pliocene, especially in the surroundings of San Gimignano (Siena). Piacentian, in yellow sands. Specie piuttosto comune nei dintorni di San Gimignano (Siena), specialmente nelle sabbie gialle del Piacenziano.

Gastropoda Rissoidae Alvania Alvania cancellata

Description

(O.D.) Turbo minimus albus cancellatim vel decussatim striatus. Cancellatus. Tab. 8. Fig. 6 & 9. Buccinum, parvum, integrum, ore perpendicolari, minimum, striis minutissimis cancellatum, subalbidum. Gualt. I. Conch. tab. 44 fig. X. X. Cimex. Turbo testa oblongo-ovata, striis decussatis: punctis eminentibus. Lin. S. N. p. 3233. No. 609.

The shell is very small, hardly double, the size of a caraway feed, of a taper shape, totally milk white, rather thick, and with no gloss. It is wrought all over with a deep latticed work, formed by thick ridges, which run spiral and longitudinal, so as to cross or decussate each other. The mouth is round, and it has no umbilicus. The spire hare four. They gradually decrease to a bluntish tip, and are seperated by a strong furrow.

Protoconca giri 2,25 convessi, ornati da 9 file di minuscole papille. Il nucleo è percorso da file di minutissime papille. Sull’ultimo giro le papille situate sulla seconda fila, presso la sutura anteriore, si allungano fino a formare un’irregolare stria ondulata a tratti interrotta. Quelle della prima e della terza fila, leggermente oblique, si dispongono senza congiungersi con la parte anteriore rivolta verso la stria centrale. Nel resto del giro le papille diminuiscono di numero e degradano regolarmente avvicinandosi alla sutura posteriore (Chirli, 2006).

Protoconch whorls 2.25, convex, with 9 rows of tiny papillae. The nucleus is crossed by rows of very tiny papillae. On the last whorl of protoconch the papillae located on the second row, near the anterior suture, stretch out to form an irregular wavy stria, sometimes interrupted. Those of the first and third row, slightly oblique, are arranged without joining the front facing the central stria. In the rest of the whorl the papillae decrease in number and degrade regularly, approaching the posterior suture.

Bibliographic references and some more common synonyms

1778 Turbo cancellatus – Da Costa, p. 104, pl. 8, figs 6, 9

1836 Rissoa crénellée – Michaud, p. 13, fig. 10

1892 Alvania cancellina – Locard, p. 157

1972 Acinopsis venter – Nordsieck F., p. 188, pl. R VII, fig. 3

1895 Alvania (Acinopsis) cancellata v. turritior – Sacco, p. 27, fig. 65

2021 Alvania cancellata – Chirli & Forli, p. 100, pls 72, 73, 74, figs A1-18, A1-19, A1-4

Stratigraphic distribution

Miocene – some specimens from Montegibbio, Emilia-Romagna. Pliocene – Portugal, Spain and Italy, where is reported how A. crenulata by De Stefani. Pleistocene – Italy, Greece and Rhodes Island, Balearic Islands (Spain) and Morocco. Recent – Atlanto-mediterranean species, reported from Madeira and Tangeri, it lives between mud,debris and algae of meso-infralittoral zone.

References

Chirli C. & Forli M., (2021). The Family Rissoidae Gray, 1847 from Miocene to Present-day, in the Mediterranean Basin. Edizioni Danaus, Palermo

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Acknowledgements

Si ringrazia l’amico Carlo Chirli (Tavarnelle, Firenze) per la concessione all’uso di alcuni suoi testi. See also Edizioni Danaus