The species name refers to the distinctly polygonal shape of the depressions that appear in the center of each sternite in the anterior part of the body.

[3] The posterior margin of the labrum features a relatively deep concave arch in the middle and denticles that are short and obtuse.

The sternite of the ultimate leg-bearing segment has the shape of a trapezoid that is longer than wide (with a length/width ratio of 1.5).

The basal element of the ultimate legs features pores on both the ventral and lateral surfaces.

This species, like E. polygonatus, features short and obtuse denticles on the labrum, one pair of lappets on the appendages of the first maxillae, anal pores, and small bulges on the first three article of the forcipules but no denticle on the ultimate article.