Alvania rudis (Philippi, 1844)
Western and central Mediterranean. Often epiphytic, the species lives in intertidal to circalittoral algal environments. Grazer and detritus feeder.
Original taxon: Rissoa rudis.
Subadult. 3m deep, Malága, Andalucia, S. Spain. 2mm.
Original description: « Testa elongata, subturrita; anfractibus convexis, superioribus costulatis, omnibus lineis elevatis transversis asperis; apertura ovata simplici, dimidiam spiram aequante. […] Whorls 61/2, all convex, the two upper ones smooth, the three following spiked with close longitudinal costae and elevated transversal striae (6 in the penultimate whorl, 10 in the last one). Aperture ovate. Colour hyaline, stained with dark reddish blotches. » – R. A. Philippi: Enumeratio molluscorum Siciliae, Berlin 1836-1844, via BHL.

Rochelongue beach, Agde, Hérault, S. France. 2,65mm.
Rochelongue. 1,95-2,75mm.
Sculptured specimen from Benalmádena, Malága. 3,5mm.
Original pictures provided by S. Gofas for WoRMS.
– (CC BY-NC-SA) –
 
Differences between A. rudis and A. litoralis van Aarsten & Menkhorst: A. rudis has a smaller protoconch and bears only one spiral cord on the second teleoconch whorl whereas A. litoralis has four. Also, in rudis, the spiral sculpture is less developed than the axial sculpture, while they are of equal strength in litoralis.
Colour and strength variation of the spirals in the same form.
Beach drift, Plage de la Franqui, Leucate, Occitania, S. France. 2,4-2,8mm. Original pictures provided by S. Clanzig (FR).
– (CC BY-NC-SA) –
Rochelongue. 2,95mm.

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