Marsh grass shrimp

Palaemonetes vulgaris

Family Palaemonidae - grass shrimps

Distinguishing
Characteristics
Body shrimp-like; carapace smooth; color light tan or white, translucent to transparent; 2nd abdominal segment overlaps the 1st segment; 1st 2 pair of walking legs chelate (clawed), 3rd pair never chelate; 2nd legs longer and more robust than 1st; movable finger (dactylus) of 2nd leg with 2 tiny teeth on cutting edge, immovable finger with 1 tiny tooth on cutting edge; carpus (segment next to chela) of the 2nd legs whole, not separated into segments; upper rostrum with 8-11 teeth, 2 of which are behind the orbit margin, 3-5 teeth on lower margin of rostrum, 1st upper tooth near tip of rostrum; rostrum slightly upcurved; no hepatic spine present; no dorsolateral grooves on posterior carapace or last abdominal segment; 1st 1/2 of body widest, with distinct bend in middle and tapering to tail end; a small shrimp.
Similar Species
Differs from penaeids by having the 2nd abdominal segment overlap the 1st segment; differs from the Ohio shrimp by lacking a hepatic spine (spine on cheek) and a daggerlike rostrum tip (no tooth near tip); most similar to daggerblade grass shrimp but has a tooth near the tip of the rostrum and 2 upper rostral tooth behind the orbit margin (1 in daggerblade grass shrimp).
Habitat
Bays, prefers submerged vegetation
Maximum Size
4.2 cm (1 1/2 in)
Other Common Names
Previous Scientific Names
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