Scylla serrata (often called mud crab or mangrove crab, although both terms are highly ambiguous, and black crab) is an ecologically important species of crab found in the estuaries and mangroves of Africa, Australia, and Asia. In their most common forms, their shell colours vary from a deep, mottled green to very dark brown. Distribution. The natural range of S. serrata is in the Indo-Pacific. https://en.wikipedia.org/wiki/Scylla_serrata