Physical Description

Daranus megistos is a large, attractive and immediately recognisable hermit crab. Growing to 30cm, though typically of more modest sizes from the reef flat, D. megistos is certainly the largest species of hermit crab from the waters of Heron Island. D. megistos is coloured a deep red blending to an orange-yellow dorsally and patterned with distinct black-lined white spots of various sizes. It has a hairy appearance, being covered with long setae, densely so on the pereopods but sparsely from the carapace. In this way and together with its size, it is initially mistakable only to D. lagopodes on Heron Island, another hairy species. The carapace of D. megistos is quite elongate, black vein-like lines extend across the gill chambers and the abdomen is of a more monochromous dark red with more regular small white spots. Typical of diogenid hermit crabs, including Dardanus, the left cheliped is larger and D. megistos is suspected to be sexually dimorphic, males being larger and with a larger left cheliped.

Photo: Arnault Gauthier, Heron Island, 2012