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).