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, 1900
Hoplobunus apoalensis Goodnight & Goodnight, 1973 — Mexico
Hoplobunus barretti Banks, 1900 — Mexico
Hoplobunus boneti (Goodnight & Goodnight, 1942) — cave, Mexico
Hoplobunus madlae Goodnight & Goodnight, 1967 — Texas
Hoplobunus mexicanus (Roewer, 1915) — Mexico
Hoplobunus mexicanus (Sørensen, 1932) — praeoccuppied; Mexico
Hoplobunus oaxacensis Goodnight & Goodnight, 1973 — Mexico
Hoplobunus osorioi (Goodnight & Goodnight, 1944) — Mexico
Hoplobunus planus Goodnight & Goodnight, 1973 — Mexico
Hoplobunus queretarius Silhavy 1974 — Mexico
Hoplobunus russelli Goodnight & Goodnight, 1967 — Texas
Hoplobunus spinooculorum Goodnight & Goodnight, 1973 — Mexico
Hoplobunus zullinii Silhavy 1977 — Mexico
Karos Goodnight & Goodnight, 1944 — Mexico
Karos barbarikos Goodnight & Goodnight, 1944
Karos brignolii Silhavy 1974
Karos depressus Goodnight & Goodnight, 1971
Karos dybasi (Goodnight & Goodnight, 1947)
Karos foliorum (Goodnight & Goodnight, 1945)
Karos gratiosus Goodnight & Goodnight, 1971
Karos parvus Goodnight & Goodnight, 1971
Karos projectus Goodnight & Goodnight, 1971
Karos rugosus Goodnight & Goodnight, 1971
Karos tuberculatus (Goodnight & Goodnight, 1944)
Karos unispinosus (Goodnight & Goodnight, 1946)
Mexotroglinus Silhavy, 1977
Mexotroglinus sbordonii Silhavy, 1977 — Mexico
Paramitraceras F. O. P-Cambridge, 1905
Paramitraceras femoralis Goodnight & Goodnight, 1953 — Mexico
Paramitraceras granulatus F. O. Pickard-Cambridge, 1905 — Guatemala, El Salvador, Mexico
Paramitraceras hispidulus F. O. Pickard-Cambridge, 1905 — Guatemala, Belize, Mexico
Sbordonia Silhavy 1977 — Mexico
Sbordonia armigera Silhavy 1977
Sbordonia parvula (Goodnight & Goodnight, 1953)
Stygnopsis Sørensen, 1902 — Mexico
Stygnopsis robusta (Goodnight & Goodnight, 1971)
Stygnopsis valida (Sørensen, 1884)
Tampiconus Roewer, 1949
Tampiconus philippii Roewer, 1949 — Mexico
Troglostygnopsis Silhavy, 1974 — Mexico
Troglostygnopsis anophthalma Silhavy, 1974
Troglostygnopsis inops (Goodnight & Goodnight, 1971)
