Cephalon: with opisthoparian sutures; glabella elongate, sides often concave (pestle-shaped), furrows (when not effaced) typically with splayed arrangement, the hind pair pointing sharply backwards, and anterior pairs tending more and more forward directed; sometimes furrows pit-like; cranidial borders often ledgelike; hypostome conterminant or (in derived forms) impendent; eyes typically large, in some gently arcuate.
Thorax: typically with 7-8 segments (but range for order is 2-12, rarely more), pleural tips often spinose.
Pygidium: typically large (isopygous or subisopygous), of variable form, sometimes spinose. 
Other: similar metaprotaspides across the three suborders of Corynexochida (bearing a hexagonal form, glabella expanding forward, a pair of anterior pits, and 1-2 pairs of posterior spines), support an hypothesis of shared lineage.
Occurrence: Lower Cambrian – Upper Devonian
Suborders: Corynexochina, Illaenina, Leiostegiina (see below).

Cephalon: with opisthoparian sutures, anterior sutures generally subparallel; glabella long, subparallel, or expanding anteriorly; eyes typically elongate, narrow;  hypostome typically fused with rostral plate (conterminant); genal spines often present.
Thorax: with 2-12 segments (rarely more in primitive genera), pleurae typically spine-tipped.
Pygidium: variable, typically large and spinose, some with smooth border.
Superfamilies/Families: Corynexochoidea: Corynexochidae, Dinesidae, Dokimocephalidae, Dolichometopidae, Dorypygidae, Edelsteinaspididae, Jakutidae, Oryctocephalidae (including Cheiruroididae), Zacanthoididae.
Genera: Corynexochidae: Abakania, Acontheus (=Aneucanthus; =Aneuacanthus), Bonnaspis, Chatiania (=Parachatiania), Clavigellus, Corynexochella, Corynexochina, Corynexochus (=Karlia), Eochatiana, Eocorynexochus, Hartshillia, Hartshillina, Milaspis, Miranella, Olinaspis, Sanaschtykgolia, Shivelicus, Trinia.

Cephalon: typically effaced, opisthoparian facial sutures, but sutures distinctly divergent anteriorly; glabella expands forwards, lateral furrows often faint or absent; hypostome impendent (conterminant, but hypostome no longer matching anterior glabellar border); extra-axial cephalic muscle impression (lunette) present; doublure broad.
Thorax: with 8-10 segments.
Pygidium: isopygous or subisopygous, rounded posteriorly, usually with short axis.
Superfamily/Families: Illaenoidea/Illaenidae, Panderiidae, Styginidae (=Scutelluidae), Tsinaniidae
Genera: Illaenidae: Alloillaenus, Bumastoides, Dysplanus, Ectillaenus (=Wossekia), Harpillaenus, Hyboaspis, Illaenus (/Cryptonymus; =Actinolobus; =Deucalion; =Svobodapeltis), Nanillaenus, Ninglangia, Octillaenus, Ordosaspis, Parillaenus, Platillaenus, Ptilillaenus, Quadratillaenus, Snajdria, Spinillaenus, Stenopareia, Trigoncekovia, Ulugtella, Vysocania, Wuchuanella, Zbirovia, Zdicella, Zetillaenus.

Cephalon: with opisthoparian sutures; glabella usually subrectangular or quadrate, sometimes broad-based, tapering forward, lateral furrows on glabella often faint or absent; palpebral furrows and eye ridges often present; eyes often medium sized, but variable; genal spines typically present.
Thorax: up to 10 segments.
Pygidium: medium to large, broadly transverse, semicircular, subrectangular, or subtriangular; furrows often faint or absent; axis often persist along nearly full length, sometimes extending into terminal spine, or a pair of lateral spines extending from 1st and 2nd pleural field (Kaolishaniidae)
Superfamily/Family: Leiostegioidea/ Cheilocephalidae, Illaenuridae, Kaolishaniidae, Leiostegidae, Ordosiidae, Pagodiidae, Shirakiellidae.
Genera: Cheilocephalidae: Aksayaspis, Cheilocephalus (=Pseudolisania; =Zhalangtania), Emsurella, Lecanoaspis, Macelloura, Oligometopus (=Bemicella), Parakoldinia, Pseudokingstonia, Pseudokoldinia.

When Fortey (1990) added Leiostegiina and Scutelluina to the Corynexochida, it expanded the stratigraphic range of the order from solely Cambrian into the Ordovician. Late protaspide similarities justified the addition of the Illaenidae, which extends the range of Corynexochida into the late Devonian.

The pestle-shaped glabella is being found in a wide variety of ptychoparioid ontogenies, and may have been transferred into adult form more than once. If this is so, then that basis for the Corynexochida may be polyphyletic. No sister taxa for the Leiostegiina nor Illaenina have been identified among Cambrian taxa. It has been suggested that the Illaenina in particular may not be as closely related to the Cambrian Corynexochida as originally argued in Fortey (1990). Ontogenetic information for the Leiostegiina was desired in Fortey's (2001) discussion of Corynexochida relationships to clarify the situation. In 2003, Lee and Chatterton documented protaspides of Leiostegium and demonstrated strong similarities of the metaprotaspides of Corynexochina, Leiostegiina, and Illaenina, supporting their membership and relationship within the Corynexochida.

Whittington (2003) argues that at least some of the Nileidae (see Asaphida) should be considered Illaenina (in Panderiidae, above). The genus Holyoakia was transferred by Paterson & Edgecombe (2006) from Order Redlichiida (Emuellidae) to Order Corynexochida (Dorypygidae), which is reflected in the listings above; otherwise genera listings above are from Jell and Adrain (2003). 

Jell (2003) contends, largely via evolution of cranidial form, that an Early Cambrian lineage from Profallotaspis through Repinaella to Elganellus ultimately leads to early Corynexochida such as Jakutidae and Dinesidae.