Glycymeris nummaria

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Glycymeris nummaria is a saltwater clam, a marine bivalve in the bittersweet clam family Glycymerididae. The shell grows up to about 60 millimetres, is thick and almost circular, and has radiating grooves with fine concentric lines. The outside is dull and can be dark or pale brown, sometimes whitish-yellow; the inside is glossy white or pale yellow, often with brown markings. It lives on the seafloor in sandy to muddy gravel, down to about 100 metres deep, from Norway to the Mediterranean. It has existed since the Pliocene era and is still alive today.