The spider family Telemidae includes 61 described species. The family has a broad distribution, but around half the known species are from China (mainly in the genus Telema and mostly described between 2008 and 2010), with just the four species of Usofila known from North America north of Mexico. (Platnick 2014) Usofila (two of which, U. flava and and U. pacifica, are known only from female specimens) are found from Alaska south to central California and east to montane Alberta and Colorado (Bennett and Ledford 2005). These tiny (<2mm), six-eyed spiders are found in moist conditions in leaf litter, under rocks, and especially in caves, where they can be very abundant. They build small sheet webs (similar to those constructed by leptonetids) beneath which they hang. Males and females may be found together in the same web for several weeks. The sub-oval egg sacs are deposited on the outer margins of the web. Troglobitic (cave-dwelling) species produce small numbers of large eggs whereas their epigean (surface-dwelling) relatives produce numerous smaller ones (D. Ubick pers. comm. cited in Bennett and Landford 2005). Individuals can be reared to maturity on a diet of freshly killed Drosophila fruit flies so long as moisture levels are adequate. (Bennett and Ledford 2005)
Telemids have a distinctive transverse zigzag ridge on the anterodorsal (front top) surface of the abdomen, visible under a microscope, and, in females, a dorsal brush of distinctive short, stout, and abruptly tapered macrosetae (spiny hairs) on the palpal tarsus (Bennett and Ledford 2005). They possess unusual glands on their tibiae that may produce defensive compounds (Bennett 1989 and references therein). Telemids often turn green when preserved in alcohol (Bennett and Ledford 2005; Bradley 2013).
Bennett and Ledford (2005) reviewed the taxonomic history of this group. Telemidae is closely related to Leptonetidae and Ochyroceratidae. Bennett and Ledford noted that, based on work begun by the late W.J. Gertsch (D. Ubick pers. comm. cited in Bennett and Ledford 2005), many specimens of undescribed species, including eyeless ones, are present in museum collections (Tracy Audisio, Joel Ledford, and Charles Griswold have pursued some molecular phylogenetic studies of undescribed troglobitic Usofila in California). They also noted that Usofila (which includes all four described Nearctic telemids) is considered by some specialists to be a junior synonym of the mainly Palearctic genus Telema.
Telemidae, also known as long-legged cave spiders, is a family of small haplogyne spiders. Most are cave dwelling spiders with six eyes, though some do not have any eyes at all. There are about 104 described species in sixteen genera.[1]
The legs are long, thin, relatively spineless, and do not have trichobothria. They have three pairs of spinnerets, the longest of which is toward the head. Instead of book lungs, they have two pairs of tracheal spiracles. The elongate abdomen bears a hardened ridge above the pedicel running in a zigzag pattern that is more clearly defined in males than females. The pedipalp on males is oval and bag-like with a thin spermatophore. The female pedipalp does not have a claw.[2]
As of July 2022, the World Spider Catalog accepts the following genera:[1]
Telemidae, also known as long-legged cave spiders, is a family of small haplogyne spiders. Most are cave dwelling spiders with six eyes, though some do not have any eyes at all. There are about 104 described species in sixteen genera.
