Prioniodontida, also known as the "complex conodonts", is a large clade of

conodont Conodonts ( Greek ''kōnos'', " cone", + ''odont'', "tooth") are an extinct group of agnathan (jawless) vertebrates resembling eels, classified in the class Conodonta. For many years, they were known only from their tooth-like oral elements, whi ...

s that includes two major evolutionary grades; the Prioniodinina and the Ozarkodinina. It includes many of the more famous conodonts, such as the giant ordovician ''

Promissum ''Promissum'' is an extinct genus of conodonts, primitive chordates, that lived during the Upper Ordovician period. A conodont, ''Promissum'' had a primitive mouth under its eyes with mineralized teeth, which are both typical for conodonts. It h ...

'' (Prioniodinina) from the Soom Shale and the

Carboniferous The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carboniferou ...

specimens from the Granton Shrimp bed (Ozarkodinina). They are euconodonts, in that their elements are composed of two layers; the crown and the basal body, and are assumed to be a

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English ter ...

Phylogeny

This is a recent cladogram of the Prioniodontida, simplified from Donoghue ''et al.'', (2008).

Notes

References

{{Taxonbar, from=Q6581502 Vertebrate unranked clades