Class Gastropoda Cuvier, 1795
Family Rissoidae Gray, 1847
Genus Alvania Risso, 1826
Species Alvania zetlandica (Montagu, 1816)
Alvania zetlandica (Montagu, 1816)
Uncommon, surroundings of San Gimignano and Poggibonsi (Siena) in gray clays. Pliocene (Piacenzian).
Gastropoda Rissoidae Alvania Alvania zetlandica Pliocene
Original Description – Descrizione originale
(O.D.) Shell with five tumid volutions, furnished with spiral ridges; which are decussated with longitudinal elevated striae, that rise into angular tubercles at the points of decussation; at the base of the shell the spiral elevations are very prominent, and destitute of striae: the apex is obtuse; aperture nearly orbicular and marginated. Length two lines: the colour is white. This very elegantlittle shell is another new species, for which we are indebted to the researches of the Rev. Mr. Fleming, who found it on the shore of the isle of Noss in Zetland; a situation which as been little explored with a scientific eye. From this quarter many of the marine productions described by Muller and other northern continental writers may be expected, especially in the class Zoophita, of which I have already been favoured with a few of a very interesting nature, either entirely new, or not described as British.
SEM – Protoconca giri 2,5 con apice elegantemente reticolato. Il reticolo è formato da filetti spirali e da esili rughe assiali zigzaganti che danno origine a maglie irregolarmente alternate, più alte che larghe. Ultimo giro ornato da tre esili filetti spirali tubercolosi, due presso la sutura anteriore e il terzo meno evidente a metà del giro (Chirli, 2006).
Protoconch, 2.5 whorls, with reticulated apex. Reticulate formed by spiral threads and thin zigzagging axial wrinkles, that give rise to irregularly alternated meshes, higher than wide. Last whorl with three slender tuberculated threads, two near the anterior suture and the third, less evident, halfway around the whorl.
Bibliographic references and some more common synonyms
1816 Turbo zetlandicus – Montagu, p. 194, pl. 13, fig. 3
1844 Rissoa canaliculata – Philippi, p. 223, pl. 23, fig. 19
1847 Rissoa carinata – Aradas, p. 74
1895 Manzonia (Flem.) zetlandica v. taurogracilis – Sacco, p. 30, fig. 75
1895 Manzonia (Flem.) zetlandica v. taurohirta – Sacco, p. 30, fig. 76
2006 Alvania zetlandica – Chirli, p. 39, pl. 19, figs 9-16
2021 Alvania zetlandica – Chirli & Forli, p. 191, pls 154, 155, 156, figs B1-14, A1-19, A1-10
Stratigraphic distribution
Miocene – reported from Bulgaria, Italy and Poland. Pliocene – Italy and Spain. Pleistocene – Italy. Recent – Atlanto-Mediterranean species, reported until to the coasts of Norway, lives between the mud and the debris in the underwater coastal plains.
References
Chirli C. (2006). Malacofauna Pliocenica Toscana – Caenogastropoda. Vol. 5, pp. 144, 46 Plates.
Montagu G. (1816). An account of some new and rare marine British shells and animals. Transactions of the Linnean Society of London. 11(2): 179-204, pls 12-14 [“1815”; 24 January 1816]., available online at http://biodiversitylibrary.org/page/756731
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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.
