Dwarf spiders

Overview

Ceraticelus is a genus of very small spiders commonly known as dwarf spiders, a name shared with other members of the subfamily Erigoninae. There are 36 Ceraticelus species, worldwide, 31 species in North America north of Mexico, and at least 6 species in Minnesota.

Ceraticelus spiders are common but seldom seen due to their small size. They are found on the ground among dead leaves, under stones, in bark crevices, and on low vegetation. They build small sheet webs on or near the ground, or on the underside of a leaf, to capture springtails, mites, and other tiny fauna.

Description

Ceraticelus spiders are very small, often less than 1⁄16″ (2 mm) in length. The body varies between species from yellowish orange, bright orange, brownish orange, to dark orangish brown.

The cephalothorax is broadly oval and rather short. The head region (pars cephalica) is black. It is usually higher in males than in females. There are eight eyes arranged as a rear row of two eyes and a front row of three pairs of closely-spaced eyes. The area defined by the eyes (median ocular area) is usually a little longer than wide. In some species, the pars cephalica of the male is divided by a furrow, it appears distinctly two-lobed, and there is one eye on each lobe.

The abdomen is fairly short and broadly oval, almost spherical. Males have a very large dorsal scutum (top plate) that often covers most of the upper surface of the abdomen. It is typically darker in color, but the amount of contrast varies between individuals. They also have an epigastric scutum (a plate on the underside surrounding the pedicel). Females also have sclerotized plates, but they are much smaller and less obvious. They typically have a small dorsal sclerite (often just a small patch or a few small spots) and a reduced ventral plate.

Distribution

Sources

30, 82, 83.

Ceraticelus Simon, 1884 in GBIF Secretariat (2023). GBIF Backbone Taxonomy. Checklist dataset https://doi.org/10.15468/39omei accessed via GBIF.org. Accessed 3/15/2026.