Montana Field Guide

This species of tadpole shrimp (order Notostraca) is a member of the crustacean class Branchiopoda. Their large, hardened carapace (shell) makes them look like a fat tadpole swimming through the water or crawling along the bottom. They are important components of many freshwater and saline intermittent or temporary wetlands (Dodson and Frey 2001 and Brendonck et al. 2008). These animals are especially common in seasonal wetlands, where populations are maintained by banks of resting eggs that may remain dormant and can survive drying periods of decades or longer (Brendonck 1996).

Nuchal organ is behind a line drawn between posterior apices of eyes; 30 to 35
body rings, 50 to 78 pairs of legs; caudal lamina subrectangular or truncate, 0.1 to 0.3 times length of carapace; sulcus spines acute, 1.3 to 1.5 times as long as broad, 2 to 5 small spines separating larger spines (Rogers and Fugate 2001).