crabs

Halicarcinus varius (Dana, 1851)
Class Malacostraca Order Decapoda Infraorder Brachyura Family Hymenosomatidae
classification
variable pillbox crab
morphology surface substrate habitat
1 cm
image: Chris Woods
Flattened carapace, pear-shaped and narrowing slightly towards the head, uninterrupted by angles;
with small tooth at extreme edges. Upper carapace surface sparsly covered with fine, curved setae.
Rostrum originating at carapace level and forming horizontal platform with apex either distinctly
or weakly trilobed, does not extend past level of the eyes, has tuft of setae. Chelipeds hairy and
almost twice the carapace length in mature males. Sparse hairs along margins of walking legs.
Carapace in large males predominantly dark brown, others pale green. White or yellow blotches
at base of last pair of legs. Cheliped fingers white tipped with red/orange band. Legs brown and
unbanded.
Endemic, widely distributed around NZ, including Stewart, and Chatham Islands. Littoral zone in
sheltered areas under algae, on rocks or under stones, in seagrass (Zostera) or harbour flats and in
sandy areas. Common subtidally in seaweed (Carpophyllum sp., Sargassum sp., Hormosira sp.) and
associated with some bivales (Maoricolpus sp., Dosinula sp., Tawera sp.). Not found where there is
high level of silt. Intertidal to 30 m.
It could also be……….
Halicarcinus spp.
Halimena aoteoroa
Melrose, M. J. (1975) The marine fauna of New Zealand: Family Hymenosomatidae (Crustacea, Decapoda, Brachyura). New Zealand Oceanographic Institute
Memoir 34: 1–123.
Yaldwyn, J.C., Webber, R.W. (2011) Annotated checklist of New Zealand Decapoda (Arthropoda: Crustacea). Tuhinga 22: 171-272.
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