Agnostida

Agnostida Temporal range: Cambrian Stage 3 –Late Ordovician PreꞒ Ꞓ O S D C P T J K Pg N
Itagnostus interstrictus
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
(unranked):	†Artiopoda
Subphylum:	†Trilobitomorpha
Class:	†Trilobita (?)
Order:	†Agnostida Salter, 1864
Families
Suborder Agnostina Superfamily Agnostoidea Agnostidae Ammagnostidae Clavagnostidae Diplagnostidae Doryagnostidae Glyptagnostidae Metagnostidae Peronopsidae Ptychagnostidae Spinagnostidae Superfamily Condylopygoidea Condylopygidae Suborder Eodiscina Superfamily Eodiscoidea Calodiscidae Eodiscidae Hebediscidae Tsunyidiscidae Weymouthiidae Yukoniidae
Synonyms
Isopygia Gürich, 1907 Miomera Jækel, 1909

Agnostida are an order of extinct arthropods which have classically been seen as a group of highly modified trilobites, though some recent research has doubted this placement. Regardless, they appear to be close relatives as part of the Artiopoda.^[1] They are present in the Lower Cambrian fossil record along with trilobites from the Redlichiida, Corynexochida, and Ptychopariida orders, and were highly diverse throughout the Cambrian. Agnostidan diversity severely declined during the Cambrian-Ordovician transition, and the last agnostidans went extinct in the Late Ordovician.^[2]