Mictomerus is an extinct genus of Cambrian euthycarcinoids from the Potsdam Group of Quebec, Canada.

The genus contains a single species, Mictomerus melochevillensis, known from 29 specimens, all but one preserved ventrally.

Mictomerus likely lived in intertidal regions, with brief forays onto land evidenced by trackways, feeding on microbial mats and detritus via gnathobases (inferred from the very closely spaced limbs and ventromedial groove).

The limbs of Mictomerus are much more robust than other euthycarcinoids, suggesting it walked along the bottom when moving through water.

[1] It also may have burrowed into mud as an anti-desiccation measure, as evidenced by casts preserved at the end of Cruziana-like fossils.