small mediterranean sea snail, known as steromphala divaricat

steromphala divaricata divaricate gibbula species small sea snail top snails marine gastropod molluscs pea gravel beach blue sky summer season mediterranean barcelona spain conoidal shell thick solid cinereous purpleish rosered lines lirulae crushedrock pebbles shoreline seawalled environs seawall impacting erosion pebble roundish interstitial areas shelled texture mollusks animals fauna nature natural light sunny closeup macro cone conical shape biology calcite mollusk invertebrate life