title: Ammagnostidae
text: # Ammagnostidae
  
  Ammagnostidae is a family of trilobites in the suborder Agnostina, small, eyeless, isopygous trilobites with a thorax consisting of 2 segments only. Four genera have been assigned to it:
  
  ## Ammagnostus Öpik, 1967
  
  * Ammagnostus psammius Öpik, 1967 (Type)
  * Ammagnostus bassus (Öpik, 1967)
  * Ammagnostus bella Guo & Luo, 1996
  * Ammagnostus beltensis (Lochman, 1944)
  * Ammagnostus cryptus
  * Ammagnostus cylindratus Guo & Luo, 1996
  * Ammagnostus duibianensis Lu & 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 & Robison
  
  ## Hadragnostus Öpik, 1967
  
  * Hadragnostus las Öpik, 1967 (Type)
  * Hadragnostus edax Fortey & Rushton, 1976
  * Hadragnostus helixensis Jago & Cooper, 2005
  * Hadragnostus modestus (Lochman, 1944)
  
  ## Kormagnostus Resser, 1938
  
  * Kormagnostus simplex 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 Butts, 1926
  
  * Proagnostus bulbus Butts, 1926 (Type)
  * Proagnostus centerensis Resser, 1938
  * Proagnostus maryvillensis Resser
  
  They lived during the late Cambrian period to the Ordovician period.
  
  