Ischyropsalidae Simon, 1879a: 265 (compr. Ischyropsalis, Sabacon, Taracus); type genus Ischyropsalis C.L. Koch, 1839b as inferable from the stem of the family name (ICZN 11.7.1.1);— Roewer 1914: 100 (compr. Ischyropsalis, Sabacon, Taracus, Tomicomerus), 1923: 680, 1950: 11; Dresco 1970: 1212 (compr. Ischyropsalis, Nipponopsalis, Taracus, Tomicomerus); Shear 1975: 11; Gruber 1978: 105.
Ischyropsalididae — Martens 1969: 184–186 (compr. Ceratolasma, Nipponopsalis, Ischyropsalis, Sabacon, Taracus); new composition (compr. Acuclavella, Ceratolasma, Ischyropsalis).
Diagnosis. Dyspnoi of the superfamily Ischyropsalidoidea with a western Palearctic and western Nearctic distribution. Defined by peculiarities of glans penis morphology, composition of the sternal region, and supported by molecular phylogenetic evidence. Palps without bottlebrush-shaped hairs, distal articles with dense cover of microtrichia, claw rudiment present. Chelicerae of moderate size, enlarged in Ischyropsalis. Except for few cavespecies in Ischyropsalis males with glandular fields on the dorsal cheliceral segment, these partly associated with apophyses. Truncus penis simple, filled up to two thirds with a single muscle; muscular tendon short; base of truncus divided into two short root-like structures.
Glans penis simple and conical, separated into two sclerotised areas: dorsally the continuously sclerotised portion of the truncus and ventrally an isolated sclerotised plate set with uniform spines of variable length; both sclerotised portions gradually tapering into and joined at the long stylus. Stylus simple, long and tapering, either bent at the base (Ischyropsalis) or set with indistinct hook-like structures. Ovipositor short and stout, without large papillae, opening cleft of vagina bordered by a seam of microspinules, medium-sized setae on apical part only, arranged into rows and clusters. Frontal margin of opisthosoma without a median furrow. Coxae II to IV with sternal apophyses, labium large. Two or more bump- or spine-like metapeltidial structures present, the median ones largest.