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
3-7 (but not more) units (picture),
no rostrum (picture),
and eyes at least partly covered dorsally by the carapace (picture).
Betaeus harrimani has a convex frontal margin of the
no indentation (picture), and
the propodus of its
cheliped is more than twice as long as wide (picture).
There is a triangular plate at the base of each uropod. The
and outer uropods are similar in length and longer than the
Its body is transparent except where pigmented. Length to
mm. Close inspection shows many red pigment cells
often surrounded by dark blue spots. Appears reddish during
and dark blue at night.
Betaeus harrimani Rathbun, 1904
Common name(s): Northern hooded
|Betaeus harrimani from Royal Palm
State Beach, Long Beach, CA.
About 3 cm long.
|(Photo by: Dave Cowles
How to Distinguish from
Similar Species: B.
setosus has an indentation on the frontal edge of the
the hand of its propodus is about as wide as long.
Geographical Range: Sitka,
Alaska to Dana
Depth Range: Intertidal,
probably also subtidal
low intertidal rocks, logs,
and debris, mostly on protected shores; on mud flats, especially in the
burrow of Upogebia
pugettensis and Neotrypaea (formerly
This is an actively
moving and usually well-camouflaged shrimp. Eggs are bright
Females in British Columbia carry eggs from June to September.
and Carlton, 1975
et al., 1980
and O'Clair, 1998
General Notes and
Observations: Locations, abundances,
In this side view, the hood that covers the eyes can be seen.
Animal total length is 3 cm. Photo by Dave Cowles, July
Captured in a Upogebia
Photos of features used for identifying this species:
All 5 "walking" legs (pereopods). Leg 1 = chelae, leg 2 is
and the carpus is subdivided into sections (visible in the picture,
of all Alpheids). Legs 3-5 are for walking.
There is no rostrum nor indentation on B. harrimani--the
end of the carapace is rounded.
Authors and Editors of Page:
Dave Cowles (2005): Created original page