About Helograpsus haswellianus (Whitelegge, 1890)
Helograpsus haswellianus, commonly known as Haswell’s shore crab, is the only crab species in the genus Helograpsus. It is found in river mouths and bays along the eastern coast of Australia, ranging from South Australia to Queensland, and also occurs in Tasmania. Its carapace is strongly convex with one distinct notch located behind the eye. Adult males of this species have larger claws than adult females. The carapace can be olive, dark slate grey, or reddish in color, and the claws of adult males are orange-yellow. The carapace can grow up to 30 millimeters wide. The orange coloration of these crabs is more intense when they live in habitats with lower pollution levels. Helograpsus haswellianus inhabits tidal saltmarshes, and is capable of being active at night. This species constructs burrows that are 30 to 40 centimeters deep above the high tide level, and it lives at the highest shore levels occupied by any marine crab. Its burrows can be built in dirty sand or mud, and the crab can also be found hiding under rocks. Individual crabs typically range up to 20 meters away from their burrows. The burrows built by this species increase the surface area of shore sediments exposed to saltwater, and help maintain the health and condition of tidal marshes. Chasmagnathus convexus and Chasmagnathus haswellianus are recognized synonyms of Helograpsus haswellianus.
