Family COENOBITIDAE Dana, 1852

Coenobita perlatus [from Alcock 1905: pl. 14 fig. 2]

Museums

Regional Maps

• Cenobitidae Dana, J.D. 1852. Crustacea. U. S. Exploring Expedition. During the years 1838, 1839, 1840, 1841, 1842. Under the command of Charles Wilkes, U.S.N. Philadelphia : C. Sherman Vol. 13 1618 pp. [Pt 1: 1–685; Pt 2: 686–1618] [432].

  Type genus:

   Coenobita Latreille, 1826.

Introduction

Coenobitids form a small family of circumtropical, semiterrestrial hermit crabs. Adult coenobitids are fully terrestrial, but they still migrate to the sea to release planktonic zoeae. Species of Coenobita are commonly known as 'land hermit crabs'; and perhaps the best known to Australians is Coenobita variabilis which is often sold in the pet industry under the name of 'crazy crabs'. The most spectacular member of the family is the Coconut Crab, Birgus latro. It is the largest known land arthropod, growing up to 2.5 kg in weight, and is prized as food where it occurs. While this species is not found on the Australian mainland it is widespread on the more oceanic islands of the tropical Indo-west Pacific, and is abundant on Australian protectorates such as Christmas and Cocos-Keeling Islands in the eastern Indian Ocean. The biology of this species has been reported on by Brown & Fielder (1991). The most important recent work on Australian Coenobita species is that of Harvey (1992), who finally clarified the identity of Coenobita variabilis, and described its larval development.

Diagnosis

Carapace and body mostly paguroid in form ('hermit crabs'), or with abdomen calcified and tucked under abdomen (Birgus latro); carapace well calcified. Eyestalks laterally flattened; eyes held subparallel to each other. Antennular peduncles prominently elongate, first segment deflexed; distal two segments slender and cylindrical; dorsal flagellum compressed with tip truncate. Antennae short, laterally compressed; antennal acicle small and usually fused to second peduncular segment. Third maxillipeds approximated basally; ischium with well-developed crista dentata; accessory tooth absent. Flagella of exopod of second and third maxillipeds much reduced. Chelipeds massive, left usually larger than right. Walking legs stout, longer than chelipeds. Fourth pereiopod chelate or subchelate; fifth pereiopod chelate. Abdomen bilaterally asymmetrical, segments not clearly marked. Male without unpaired pleopods; female with three unpaired pleopods. Uropods bearing rasp used to grasp gastropod shell (except Birgus). Fourteen paired phyllobranchiae (but only 10 functional); third maxilliped and cheliped each with two paired rudimentary arthrobranchs.

General References

Brown, I.W. & Fielder, D.W. (eds) 1991. The Coconut Crab: aspects of Birgus latro biology and ecology in Vanuatu. Canberra : Australian Centre for International Agricultural Research (ACIAR) Monograph No. 8 ix 128 pp.

Harvey, A.W. 1992. Abbreviated larval development in the Australian terrestrial hermit crab Coenobita variabilis McCulloch (Anomura: Coenobitidae). Journal of Crustacean Biology 12(2): 196-209

History of changes