Extensive work, particularly during the last 25 years, has led to the recognition of several hundred species and more than 100 genera of Cambrian, Ordovician, and Silurian conodonts. Wide distribution, short vertical range, and abundant occurrence have made conodonts some of the best early Paleozoic index fossils known. Most detailed conodont work has been done in North America and Europe but significant data are available from South America, Asia, and Australia. Cambrian conodonts, still poorly known and apparently not greatly varied taxonomically, are less useful biostratigraphically than Ordovician and Silurian conodonts. No Cambrian conodont zone succession has been proposed but some conodonts have considerable stratigraphic potential in the Late Cambrian. Ordovician onodonts are characterized by explosive taxonomic diversification and striking provincial differentiation. Two sequences of 15 to 20 conodont zonal units are in common use, one in each main province. Conodonts permit, in many places, a greater stratigraphic resolution than is achieved using any other fossils. Silurian conodonts are less diversified taxonomically (about 15 genera) and less differentiated provincially than those of the Ordovician. They form the basis of a succession of about 15 standard zones. Both Ordovician and Silurian conodonts have been tied into graptolite biostratigraphy producing a detailed and regionally useful framework.

Apart from various aspects of biostratigraphy, biogeography, and taxonomy, current early Paleozoic conodont research includes paleoecology which has resulted in a greatly improved understanding of the environmental significance of these enigmatic fossils.

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