Archaeomysis grebnitzkii

Taxon-Order: 
Mysidacea

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Distribution: 
North Pacific to southern California.
Habitat: 
Occurs in the wave wash zone of the beach, in the breaker zone and at night in surface waters.
Size: 
? - 14 mm
Diet: 
Omnivorous.
Useful Facts or Characters: 

Telson is cleft, with two equal parts; each part with small spinules along the margins.  The telson has widely-spaced spines along the lateral margins.  (Archaeomysis marculata=Archaeomysis grebnitzkii)

Antennal scale with a large tooth on its external edge.  Third pleopod of adult male is modified and much longer than the other four pleopods.

Natural History: 

Has been caught in surface waters at night off SIO Pier and can be found in the breaker zone.

References: 

http://peracarida.usm.edu/

Kathman, R.D., W.C. Austin, J.C. Saltman & J.D. Fulton (1986) Identification manual to the Mysidacea and Euphausiacea of the northeast Pacific. Canadian Special Publication of Fisheries and Aquatic Sciences 93:1-411.