Arcidae belongs to the superfamily within the order Arcoida . It is a highly species-rich family, with a conservative estimate of over 300 extant species worldwide.
: 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.
Complete mitochondrial genome of Anadara vellicata (Bivalvia arcidae
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
: Common genera include Anadara (often called blood cockles due to the presence of hemoglobin), Arca , and Barbatia . Morphological and Biological Characteristics Arcidae belongs to the superfamily within the order Arcoida
: Attached to hard surfaces (rocks, coral) via strong byssal threads . Infaunal : Buried in sand or mud. Economic and Ecological Importance
: 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. This adaptation may aid survival in low-oxygen environments
: Many species possess numerous small pallial eyes along their mantle margin, particularly on the posterior side, providing light sensitivity. Lifestyles : They exhibit two main ecological habits: