Six genera are treated .in this section They are arranged alphabetically: Cavusgnathus, Diploognathodus, Gondolella, Idiognathodus Neognathodus and Streptognathodus with their -species arranged phylogenctically. These are, by and large, considered to be -the “platform” genera most useful for biostratigraphy. Strictly speaking, Diplognathodus lacks a platform hut appears to be closely related to taxa that bear true platforms and aIso shows an evolutionary pattern much like that of platform-bearing genera.
Three other genera are numerically important in these collections, but are not discussed in detail: Aethotaxis, Anahignathodus, and Idioprioniodus. Aethotaxis Baesemann, 1973, US a coomon and paleoecologically quite important conodont. It ranges through most orall of the, Pennsylvanian System and needs detailed monographic treatment considered to be beyond the scppe of this study. Anchignathodus Sweety 1970 (the Spathognathodus of authors), faces the same platform/nonplatform difficulty as Diplognathodus. The Pennsylvanian including Illinois basing species of Anchignatihodus have been studied in some detail by Merrill (1973a). Idioprioniodus Gunnell, 1933, is another nonplatforn conodont with great paleoecologic utility. Its apparatus composition has been, studied, based mostly on material from northwestern, Illinois, by Merrill and Merrill (1974), and studies about its spation are In process. Each of these genera is discussed briefly under the heading Multielement Taxonomy.