The Stygnopsidae are a small family of harvestmen, with almost all species found in Mexico.
The name of the type genus Stygnopsis is combined from the genus Stygnus (Stygnidae) and Ancient Greek opsis, "looks like".
The body length of these harvestmen ranges from 2.5 (Karos) to 7 mm (Hoplobunus). Their color ranges from dark brown to black, with much lighter appendages. Cave-dwelling species are pale light brown.
As in other Laniatores, most species have narrow distributions. Almost all species occur in Mexico, with some found in the southern USA (Hoplobunus), and Guatemala, El Salvador and Belize (Paramitraceras).
Epedanidae could be the sister group to Gonyleptoidea sensu lato (including the Assamiidae), with the Stygnopsidae the sister group to the rest of Gonyleptoidea. Although they reach into the Nearctic, they are more closely related to neotropical harvestmen.
Hoplobunus Banks, 1900Hoplobunus apoalensis Goodnight & Goodnight, 1973 — MexicoHoplobunus barretti Banks, 1900 — MexicoHoplobunus boneti (Goodnight & Goodnight, 1942) — cave, MexicoHoplobunus madlae Goodnight & Goodnight, 1967 — TexasHoplobunus mexicanus (Roewer, 1915) — MexicoHoplobunus mexicanus (Sørensen, 1932) — praeoccuppied; MexicoHoplobunus oaxacensis Goodnight & Goodnight, 1973 — MexicoHoplobunus osorioi (Goodnight & Goodnight, 1944) — MexicoHoplobunus planus Goodnight & Goodnight, 1973 — MexicoHoplobunus queretarius Silhavy 1974 — MexicoHoplobunus russelli Goodnight & Goodnight, 1967 — TexasHoplobunus spinooculorum Goodnight & Goodnight, 1973 — MexicoHoplobunus zullinii Silhavy 1977 — MexicoKaros Goodnight & Goodnight, 1944 — MexicoKaros barbarikos Goodnight & Goodnight, 1944Karos brignolii Silhavy 1974Karos depressus Goodnight & Goodnight, 1971Karos dybasi (Goodnight & Goodnight, 1947)Karos foliorum (Goodnight & Goodnight, 1945)Karos gratiosus Goodnight & Goodnight, 1971Karos parvus Goodnight & Goodnight, 1971Karos projectus Goodnight & Goodnight, 1971Karos rugosus Goodnight & Goodnight, 1971Karos tuberculatus (Goodnight & Goodnight, 1944)Karos unispinosus (Goodnight & Goodnight, 1946)Mexotroglinus Silhavy, 1977Mexotroglinus sbordonii Silhavy, 1977 — MexicoParamitraceras F. O. P-Cambridge, 1905Paramitraceras femoralis Goodnight & Goodnight, 1953 — MexicoParamitraceras granulatus F. O. Pickard-Cambridge, 1905 — Guatemala, El Salvador, MexicoParamitraceras hispidulus F. O. Pickard-Cambridge, 1905 — Guatemala, Belize, MexicoSbordonia Silhavy 1977 — MexicoSbordonia armigera Silhavy 1977Sbordonia parvula (Goodnight & Goodnight, 1953)Stygnopsis Sørensen, 1902 — MexicoStygnopsis robusta (Goodnight & Goodnight, 1971)Stygnopsis valida (Sørensen, 1884)Tampiconus Roewer, 1949Tampiconus philippii Roewer, 1949 — MexicoTroglostygnopsis Silhavy, 1974 — MexicoTroglostygnopsis anophthalma Silhavy, 1974Troglostygnopsis inops (Goodnight & Goodnight, 1971)