Introduction

Mysmenids are one of the least studied groups of orb-weaving spiders, mainly because of their minuscule size (0.6-3 mm; Fig. 1) and cryptic life history. The family Mysmenidae is distributed worldwide, and with only around 100 described species, the diversity of mysmenids is clearly under-sampled as numerous undescribed species of this family have been collected and/or exist in museum collections around the world.

Mysmenids live mainly in leaf litter and other cryptic places in humid habitats. Mysmenid web-spinning species seem to usually prefer the interstices of leaf litter and small cavities about 5-15 cm in diameter (depending on the size of the spider) created by the top layer of leaves. They can be collected by beating foliage, using pitfall traps, Berlese funnels, Winkler devices (e.g. Wheeler and McHugh, 1987), or just manually.

Only a few mysmenid spiders have been documented from the fossil record (eight species in five genera). Seven fossil mysmenids have been described from Tertiary ambers from the Miocene (15–20 Ma; two species from Dominican amber), Miocene–Oligocene (19–27 Ma, one species from Chiapas amber), and Eocene (44 Ma, two species from the Baltic amber, and two species from the Baltic and Bitterfeld ambers). A relatively recent species was described from Madagascan copal (a semi-fossilized resin less than two million years old).