Critter of the Week: The prickly king crab

The prickly king crab, Paralomis zealandica, is a member of the family Lithodidae, a mainly deepwater crustacean group that is probably better known by many people for its tasty leg meat.

These videos show some interesting documentaries about the history of the Alaskan king crab fishery

The prickly king crab is not a quota species in New Zealand, but some of its relations are regulated under the quota management system with some small commercial catches being made each year.

The prickly king crab, Paralomis zealandica has an even covering of robust spines all over its carapace. [P. Marriott, NIWA]

These are not the largest of the New Zealand king crabs, that title is held by Lithodes aotearoa, which can have up to a 1.3 m leg span. Paralomis zealandica can reach up to 13 cm across its carapace. However, Paralomis zealandica is one of the most widely distributed species in the genus, distributed in southern New Zealand waters from the Chatham Rise down to the Campbell and Bounty Plateaus from 254–1212 m, but normally from 550–650 m.

The prickly king crab at home on the Chatham Rise. [Oceans Survey 20/20 Chatham Challenger, NIWA, DTIS Camera]

Prickly defences

There are a lot of king crabs with prickly carapaces, but P. zealandica can be distinguished from other species in New Zealand waters by its thick covering of strong upright spines all over, including on its abdomen and along its legs and claws. The rostrum, or the bit sticking up over its eyes, has three short, strong and sharp spines.

Not a true crab

In the below top-down shot of a smaller juvenile specimen you can count three pairs of walking legs (pereopods) plus the claws (chelipeds). Interestingly, the king crabs are actually not true crabs and their fourth pair of walking legs are greatly reduced like a hermit crab, their closer crabby-like relations.

A juvenile specimen of Paralomis zealandica, collected on the Ghoul Seamount, Chatham Rise at 936 m. [Rob Stewart, NIWA. Vulnerable Deep Sea Communities]

Another shot of the juvenile specimen of Paralomis zealandica, collected on the Ghoul Seamount, Chatham Rise at 936 m. [Rob Stewart, NIWA. Vulnerable Deep Sea Communities]

Further information and references

Ahyong S. T. (2010) The marine fauna of New Zealand: King crabs of New Zealand, Australia and the Ross Sea (Crustacea: Decapoda: Lithodidae). NIWA Biodiversity Memoir 123. Order a hard copy here.

Pevious posts about the Lithodidae family and other New Zealand king crab species: