Glycymeris nummaria

Glycymeris nummaria is a species of saltwater clam, a marine bivalve mollusc in the family Glycymerididae, the bittersweet clams.

Glycymeris nummaria Temporal range: Pliocene - Recent PreꞒ Ꞓ O S D C P T J K Pg N
Right valve of Glycymeris nummaria
Left valve of Glycymeris nummaria
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Bivalvia
Order:	Arcida
Family:	Glycymerididae
Genus:	Glycymeris
Species:	G. nummaria
Binomial name
Glycymeris nummaria (Linnaeus, 1758)

Synonyms

• Arca insubrica Brocchi, 1814
• Arca nummaria Linnaeus, 1758
• Glycymeris insubrica (Brocchi, 1814)
• Glycymeris violacescens (Lamarck, 1819)
• Pectunculus cor Lamarck, 1805
• Pectunculus nudicardo Lamarck, 1819
• Pectunculus obliquatus Rayneval & Ponzi, 1854
• Pectunculus pilosellus Risso, 1826
• Pectunculus purpurascens M' Andrew, 1854
• Pectunculus reticulatus Risso, 1826
• Pectunculus transversus Lamarck, 1819
• Pectunculus zonalis Lamarck, 1819

Description

• 
  Fossil (Quaternary)
• 
  Fossil (Pliocene)

Glycymeris nummaria var. insubrica
Right and left valve of the same specimen:

• 
  Right valve
• 
  Left valve

The shell of an adult Glycymeris nummaria can be as large as 60 millimetres (2.4 in). It is quite thick, almost circular in shape, with a sculpture of radiating striae and fine concentric lines. The surface is dull and may be dark or pale brown, but also whitish-yellowish. Inside of the shell is glossy, white or pale yellow, often with irregular brown markings.

Distribution and habitat

This species is widespread from Norway to the Mediterranean Sea. It lives in sandy-muddy gravels offshore to depths of about 100 metres (330 ft).