Summary

Hermit crabs are decapod crustaceans and belong to the superfamily paguroidea, however they are not true crabs. Unlike true crabs they have an asymmetrical body and walk in a forward direction rather than a sideways direction. Hermit crabs have a soft abdomen and live in discarded gastropod shells for protection which are changed to accommodate for their growth. Worldwide there are approximately 1100 species in seven families within the superfamily paguroidea; coenobitidae (terrestrial hermit crabs), Diogenidae (left handed hermit crabs), Paguridae (right handed hermit crabs), Parapaguridae, Parapylochelidae, Pylochelidae and Pyojacquesidae. Calcinus guamensis belongs to diogenidae, the left handed hermit crabs. Calcinus guamensis is a rather understudied species, it was first described by Wooster in 1984 where it was found in the Marinana Islands and has been described few more times since with a wider distribution. It belongs to the genus calcinus, which is characterised by the white tips on the chelae.

Photo taken by Monica Pelcar, University of Queensland, 2014