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Montana Field Guide

Montana Field Guides

Hookleg Clam Shrimp - Lynceus mucronatus

Native Species

Global Rank: G3
State Rank: SNR
(see State Rank Reason below)

Agency Status


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State Rank Reason (see State Rank above)
Currently unranked at the state level. Although widely disjunct across Montana (SNR), Alberta (SNR) and British Columbia (SNR) , this species has been rarely collected.
General Description
Lynceus is a genus of clam shrimp in the family Lynceidae. There are about 13 described species in Lynceus. They generally look like a shrimp that lives inside of a small clam shell. When the shell is closed they can easily be mistaked for bivalves (peaclams).

Range Comments
This species of clam shrimp has been reported in the convergence area of the Rocky Mountains and the Cascade Mountains in Montana (SNR), Alberta (SNR) and British Columbia (SNR).

Most branchiopod species rely on seasonal wetlands such as playas, vernal (rain and snow-melt) pools, salt flats, and alkali pans, while other species occur in permanent playas, fishless alkali lakes, and salt lakes (Dumont & Negrea, 2002). These habitats are, for the most part, seasonal pools that are dry for a significant portion of the year, or several years (Dumont & Negrea, 2002).
Clam shrimp in Montana usually inhabit temporary wetlands and vernal pools, typically clear, slightly alkaline to slightly acidic, water.

Food Habits
Clam shrimp typically filter feed non-selectively on detritus and algae in suspension (Belk 1982).

Branchiopod crustaceans rely on banks of resting eggs (or ‘‘cysts’’) to bridge periods of drought or frost (Brendonck, 1996) and to buffer against the effects of environmental variability. The eggs lay dormant in the substrate until the pool dries and refills during the subsequent rains.

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Citation for data on this website:
Hookleg Clam Shrimp — Lynceus mucronatus.  Montana Field Guide.  .  Retrieved on , from