Betaeus harrimani Rathbun 1904

How to Distinguish from Similar Species: B. setosus has an indentation on the frontal edge of the carapace and the hand of its propodus is about as wide as long.

Biology/Natural History: This is an actively moving and usually well-camouflaged shrimp. Eggs are bright green. Females in British Columbia carry eggs from June to September.

Geographical Range: Sitka, Alaska to Dana Point, CA

Depth Range: Intertidal, probably also subtidal

Caridean sthrimp have the epimeron of the second abdominal segment overlapping that of segments 1 and 3. Family Alpheidae has the carpus of pereopod 2 subdivided into 3-7 units, no rostrum, and eyes at least partly covered dorsally by the carapace. Betaeus harrimani has a convex frontal margin of the carapace with no indentation, and the propodus of its cheliped is more than twice as long as wide. There is a triangular plate at the base of each uropod. The inner and outer uropods are similar in length and longer than the telson. Its body is transparent except where pigmented. Length to about 35 mm. Close inspection shows many red pigment cells, often surrounded by dark blue spots. Appears reddish during the day and dark blue at night.

Under low intertidal rocks, logs, and debris, mostly on protected shores; on mud flats, especially in the burrow of Upogebia pugettensis and Neotrypaea californiensis.