The spider family Leptonetidae includes 271 described species in Europe, Asia, and North and Central America (Platnick 2013), including 40 that occur in North America north of Mexico (Ledford et al. 2005). Many additional species are known that have not yet been formally described (Ledford 2004; Bradley 2013). These tiny spiders are found in damp, dark microhabitats under rocks, in log and leaf litter, and in caves. The web built by some is a small tangle or tightly woven sheet beneath which the spider hangs. When disturbed, it drops from the web and folds its legs close to the body. (Ledford et al. 2005; Bradley 2013)
Leptonetids have six eyes (the anterior median eyes are absent), either in a tight cluster or with one pair set well behind the others; some cave-dwelling species lack eyes altogether. The males of many species have relatively long palps and the female reproductive structures are not visible externally. An unusual feature of this family is that if a spider loses a leg, it usually separates at the joint between the patella and tibia, rather than farther toward the base, between the coxa and trochanter, as in most spiders. (Ledford et al. 2005; Bradley 2013)
Two leptonetids, Tayshaneta microps (=Neoleptoneta microps) and T. myopica (=N. myopica=Leptoneta myopica) are among the handful of spider species listed as endangered under the U.S. Endangered Species Act (Ledford et al. 2012) (Ledford et al.  concluded that Neoleptoneta was paraphyletic and segregated the species in the genus into several different genera).
Ledford (2004) reported on the morphology, distribution, and natural history of Calileptoneta, including an account of courtship and mating in Calileptoneta ubicki.
Barcode of Life Data Systems (BOLD) Stats Specimen Records:85 Specimens with Sequences:85 Specimens with Barcodes:81 Species:25 Species With Barcodes:25 Public Records:80 Public Species:25 Public BINs:2
Leptonetidae is a family of relatively primitive haplogyne (lacking hardened external female genitalia) spiders, which includes 15 genera and nearly 200 species. The family is poorly known to anybody but specialists. Leptonetids are generally tiny, have six eyes arranged in a semicircle of four in front and two behind. Many live in caves or in leaf litter. They are found around the Mediterranean, and in Eurasia, Japan and the New World[clarification needed].