Arcidae

: Attached to hard surfaces (rocks, coral) via strong byssal threads . Infaunal : Buried in sand or mud. Economic and Ecological Importance

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

: Though rare, some species are found at abyssal depths and in polar seas. : Attached to hard surfaces (rocks, coral) via

: 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. : Unlike most mollusks, Arcidae often contain hemoglobin

: 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.