Ammagnostidae

Ammagnostidae is a family of trilobites in the superfamily Agnostoidea, which is part of the order Agnostida, or small, 2 or 3 segmented trilobites. It has four genera:

Ammagnostus Öpik, 1967

Hadragnostus Öpik, 1967 Kormagnostus Resser, 1938 Proagnostus Butts, 1926
 * Ammagnostus psammius Öpik, 1967 (Type)
 * Ammagnostus bassus (Öpik, 1967) Guo and Luo, 1996
 * Ammagnostus bella Guo and Luo, 1996
 * Ammagnostus beltensis (Lochman, 1944) Robinson, 1988
 * Ammagnostus cryptus
 * Ammagnostus cylindratus Guo and Luo, 1996
 * Ammagnostus duibianensis Lu and Lin, 1989
 * Ammagnostus histus
 * Ammagnostus hunanensis
 * Ammagnostus integriceps Öpik, 1967
 * Ammagnostus laiwuensis (Lorenz, 1906)
 * Ammagnostus mitis Öpik, 1967
 * Ammagnostus sinensis Peng, 1987
 * Ammagnostus wangcunensis Peng and Robison
 * Hadragnostus las Öpik, 1967 (Type)
 * Hadragnostus edax Fortey and Rushton, 1976
 * Hadragnostus helixensis Jago and Cooper, 2005
 * Hadragnostus modestus (Lochman, 1944)
 * Kormagnostus sinplex Resser, 1938 (Type)
 * Kormagnostus boltoni Westrop et al., 1996
 * Kormagnostus copelandi Westrop et al., 1996
 * Kormagnostus flati Pratt, 1992
 * Kormagnostus inventus Shergold, 1982
 * Kormagnostus minutus (Schrank, 1975)
 * Kormagnostus seclusus (Walcott, 1884)
 * Proagnostus bulbus Butts, 1926 (Type)
 * Proagnostus centerensis Resser, 1938
 * Proagnostus maryvillensis Resser

They occurred during the late Cambrian period to the Ordovician period.