Conodonts are divided into three groups with different histologies: protoconodonts (most primitive), paraconodonts, and euconodonts (most advanced). The first is poorly known, but paraconodonts included a Westergaardodina and a coniform evolutionary lineage, and each was the ancestor of one or more euconodont lineages. Early euconodonts are thus polyphyletic and included the Proconodontus and Tendonitis Lineages, which appeared in the middle Late Cambrian, and the Fryxellodontus and Chosonodina Lineages, which appeared in the Early Ordovician. Major changes in conodont evolution, biofacies adaptation, and development of provincialism coincided with sea-level fluctuations near the end of the Cambrian (here named the Lange Ranch...