Munida quadrispina Benedict, 1902

Common name(s): Squat lobster

Phylum Arthropoda
 Subphylum Crustacea
  Class Malacostraca
   Subclass Eumalacostraca
    Superorder Eucarida
     Order Decapoda
       Suborder Pleocyemata
        Infraorder Anomura
         Superfamily Galatheoidea
         Family Galatheidae
Munida quadrispina from 100 m depth, San Juan Channel
(Photo by: Dave Cowles, July 2000)
Description:  This anomuran crustacean has a large telson which it does not tuck tightly under its thorax as seen in crabs.  It has large uropods and a well-developed tail fan, and uses the tail fan to swim backwards in the 'caridoid escape response'.  Its eyes are pigmented.  The rostrum is long and pointed, with a large supraorbital spine on each side at the base (photo).  The chelipeds are much longer than the other walking legs, slender, and spiny.  Overall color is orange or brick red.  The carapace is longer than wide, and the edge of the carapace also is lined with small spines.  Carapace length up to 6.7 cm.  The abdomen has ridges but no spines (photo) except for tiny spines on the tail fan.  Color is reddish-brown dorsally; lighter on the ventral side.  We may have several species here in the Pacific Northwest, not all of which are described.

How to Distinguish from Similar Species: Munidopsis quadrata's eyes are not pigmented plus it lives only in very deep water.

Geographical Range: Sitka, Alaska to Los Coronados, Baja California

Depth Range: 12-1463 m depth

Habitat: Rock faces or cobble in low current, slightly silty areas.

Biology/Natural History: Sometimes live in areas with low oxygen.  Eats detritus, carrion, small plankton.  This crustacean can actively swim.  They are one of the main species observed on the surfaces of deep-sea sponges off British Columbia.  They are predators on other benthic shrimp.

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Dichotomous Keys:
  Coffin, 1952
  Flora and Fairbanks, 1966
  Hart, 1982
  Kozloff 1987, 1996
  Wicksten, 2009

General References:
  Hart, 1982
  Jensen, 1995
  Lamb and Hanby, 2005

Scientific Articles:
Antonsen, Brian L. and Dorothy H. Paul, 2000.  The Leg Depressor and Levator Muscles in the Squat Lobster Munida quadrispina (Galatheidae) and the Crayfish Procambarus clarkii (Astacidae) Have Multiple Heads with Potentially Different Functions.  Brain, Behavior and Evolution  56:63-85 (DOI: 10.1159/000006678) (Link)

Antonsen, B.L. D.H. Paul, 2001.  Serotonergic and octopaminergic systems in the squat lobster Munida quadrispina (Anomura, Galatheidae).  J Comp Neurol. 2001 Oct 29;439(4):450-68 (PubMed)

Burd, B.J. 1983. The distribution, respiration and gills of a low oxygen tolerant crab, Munida quadrispina (Benedict, 1902) (Galatheidae, Decapoda) in an intermittently anoxic fjord. M.Sc. Thesis, University of Victoria, Victoria, B.C.

Burd, B.J. 1985. Respiration of a low oxygen tolerant galatheid crab, Munida quadrispina (Benedict, 1902). Canadian Journal of Zoology 63: 2538-2542.

Burd, B.J. and R.O. Brinkhurst. 1984. The distribution of the Galatheid crab Munida Quadrispina (Benedict 1902) in relation to oxygen concentrations in British Columbia fjords. Journal of Experimental Marine Biology and Ecology 81: 1-20.

Wallis, E., D. Paul, B. Antonsen, and R. Hollenberg, 1995.  Variations on a segmental theme: muscle receptor organs and extensor neuromusculature in the squat lobster Munida quadrispina (Anomura, Galatheidae).  Journal of Experimental Biology 198: 12 2453-2463

General Notes and Observations:  Locations, abundances, unusual behaviors:

Another view
A view of another individual, captured at 100-120 m depth in the San Juan Channel.  Carapace length of this individual is 2.5 cm to orbit; width is 2.0 cm.  Photo by Dave Cowles, August 2015

A view of the chelae.

A view of the abdomen.  Note that the abdomen has ridges and setae but not spines.

Authors and Editors of Page:
Dave Cowles (2005):  Created original page