Rhinolithodes wosnessenskii Brandt (1849)

Common name(s):  Rhinoceros crab

Phylum Arthropoda
 Subphylum Crustacea
  Class Malacostraca
    Subclass Eucarida
     Order Decapoda
       Suborder Pleocyemata
         Infraorder Anomura
          Family Lithodidae
Rhinolithodes wosnessenskii approx 7 cm across carapace, captured by SCUBA off Sares Head August 2004  See below for more photos.
Photo by: Dave Cowles August 2004
Description:  This lithodid crab has a carapace with a triangular outline and a very deep semicircular depression on the dorsal side.  The claws and legs are covered with spines and even longer hairlike setae. (picture)  The (antero)lateral margins of the carapace have sharp-tipped spines (picture).  The rostrum has one small point like a small rhinoceros horn (picture), leading to the name.  Color is usually yellowish-brown with orange and white.

How to Distinguish from Similar Species: The only other local Lithodid crab with a triangular carapace is Phyllolithodes papillosus (the heart crab).  It differs from that species in that P. papillosus has fewer, stiff blunt spines on the legs and few hairlike setae on the legs, has a rostrum of two blunt lobes, and the dorsal concavity of the rostrum is more strongly divided into a left and a right depression bordered by large tubercles.

Geographical Range:  Kodiak, Alaska to Crescent City, CA

Depth Range:  6-73 m

Habitat:  Rock or gravel bottoms, often hiding in crevices.

Biology/Natural History:  Not often found in most areas of Puget Sound/Straits (though this species is often found on Sares Head).  Slow-moving.  Interestingly, even the back of the eyestalks have small spines (picture)

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Dichotomous Keys:

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

General References:
  Jensen, 1995

Scientific Articles:

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

The anterior margin of the carapace is covered with sharp spines (see at the base of the hairy legs)

The rostrum has a single hornlike spine, visible from the side

The abdomen is held tightly against the underside of the thorax.  The chelipeds are covered with hairlike setae, as are the rest of the legs.

Authors and Editors of Page:
Dave Cowles (2004):  Created original page