: Maximum species diversity occurs in the Indo-West Pacific region, where over 180 valid species in more than 30 genera are recorded. Regional Presence : Tropical West Africa : ~27 species. West Atlantic : ~20 species. Northeastern Atlantic : ~10 species.
The family, commonly known as ark shells , is a diverse group of marine bivalve mollusks. These organisms are recognized by their distinct trapezoidal, ribbed shells and a taxodont hinge (characterized by many small, similar teeth). While primarily found in tropical and warm temperate shallow waters, they occupy a wide range of habitats—from coral reefs and rocky substrata to muddy estuarine environments. Taxonomy and Global Distribution arcidae
: Common genera include Anadara (often called blood cockles due to the presence of hemoglobin), Arca , and Barbatia . Morphological and Biological Characteristics : Maximum species diversity occurs in the Indo-West
: A long, straight hinge line with numerous small teeth. Northeastern Atlantic : ~10 species
The family holds significant value both as a resource and as a subject of ecological study.
: Unlike most mollusks, Arcidae often contain hemoglobin in their hemocoel, giving them a red-colored body and the name "blood cockles". This adaptation may aid survival in low-oxygen environments like mud.