Relative abundances of conodonts stem from abiotic or biotic causes. High frequencies can result from: 1) biotic positive = high standing crop; 2) biotic negative = lethality (mass mortality); 3) abiotic positive = lag concentrates; 4) abiotic negative = starved sedimentation. Neither abiotic cause should substantially affect the taxonomic composition of the fauna, although either biotic cause—good or bad environmental responses—can and must. Pennsylvanian conodont biofacies are clearly established and evidence of their interrelationships and complexity has continued to mount. We currently recognize no fewer than five levels of conodont biofacies: Ia - Primary generic-level biofacies (examples: Cavusgnathus, Aethotaxis) Ib - Secondary generic-level (“nested”) biofacies (examples: Ellisonia with Cavusgnathus, Hindeodus with Aethotaxis) II - Species-level microbiofacies (examples: Idiognathodus delicatus with Missourian Idioprioniodus / Gondolella , Streptognathodus elegantulus with Missourian Aethotaxis ) III - Apparatus-level biofacies (examples: scottognathoid apparatuses least complete with Cavusgnathus, intermediate with Aethotaxis, most with Idioprioniodus in the Missourian) IV - Ecophenotype variant-level biofacies (examples: perhaps two “species” of Ellisonia with contrasting apparatus plans and morphologies in the Desmoinesian, possible Cavusgnathus morphotypes from the Cavusgnathus- to the Streptognathodus -biofacies).

Abstract 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.

Abstract The youngest unit studied in this area is he Cramer (fomerly Trivoli) Member. Its high stratigraphic position dictates that it will be preserved only on the geographically restricted, topographically high rldgeline running froa Faralngton eastward toward Peoria (Fig. 1 ). Only two Cramer localities within the study area were saapled for conodonts. The two are HLithically dissimilar and not faunally hoaogeneous. The type locality (Wanless, 1957, p. 193) has a aasslve fairly pure limestone and an overlying nodular, argillaceous, packed mixed biomicrite, obviously weathering out of a shale. At locality 3 (Wanless, 1958, locality 169) nodular, pagked Derbya biomicrites alterna te, with shale Interbeds below the aaln limestone member (member 152). The high degrees of lithologic and faunal difference between the two successions may represent distinct stratigraphic units. Faunally, locality 1 is an offshore Aethotaxis -blofacies (1A) to Idioprioniodus -biofacies (IB) unit dominated by platform elements transitional between Idiognathodus and Streptognathodus . Locality 3 is so heavily dominated by elements of the Carusgnathus -biofacies that little else of a diagnostic nature is present. Neither locality has produced unquestioned specimens of Neognathodus or Gondotella . Absence of Neognathodus and domination by Streptognathodus canoellosus are compatible with an early Missourian assignment and suggest its (nearest correlatives to be the Lower Brush Creek .In Ohio and the Bertha in Kansas-Missouri, although aore data are needed for substantiation.. Absences are unsafe criteria for age determinations, and Wanless (1956, p. 50-51) has reported “ Metalonchodina ”, an element that is a component of Idioprioniodus and supposedly restricted to pre-Missourian nocks, to

Abstract A middle Pennsylvanian (Desmoinesian) conodont fauna was used to identify the interval represented by the Lower Kittanning cyclothem across the North American continent. The conodonts show both a succession through the cyclothem and a geographic variation that is related to the water mass and depositional environment. The faunas can be divided into normal-marine, high- and (or) variable-salinity, and high-productivity assemblages. Normal-marine faunas are dominated by Idiognathodus , which can be further divided into low-diversity and high-diversity faunas. The low-diversity Idiognathodus faunas characterize the marine deposits of the nearshore, marginal environments of the Appalachian Basin, and also the bulk of the black and gray shale and carbonate depositional environments of Midcontinent cyclothems. The high-diversity Idiognathodus faunas characterize fossiliferous limy shale and shaly limestone depositional environments typical of the shale–limestone transition in Midcontinent cyclothems and the richly fossiliferous limestone deposition in carbonate sequences in much of the western U.S., within the dolomite beds associated with sandstone deposition of the Tensleep Sandstone, and in fossiliferous limestones between sandstones and carbonate mudstones of the Paradox Basin. High-salinity and (or) variable-salinity faunas are dominated by Neognathodus and (or) Adetognathus , and characterize carbonate deposition in the Bird Spring–Ely platform, southwestern U.S., and shallow-water, typically algal facies within the Midcontinent cyclothems. High-productivity faunas are dominated by Gondolella , are extremely rare, and characterize horizons of surface substrate accumulation within black-shale and mud depositional environments. Maximum flooding within the cycle, as indicated by the highest diversity of normal-marine macrobiota and conodont fauna, does not occur in black shales but at the shale–limestone transition. Sixteen species of conodonts in eight genera are recognized in the cyclothem. The following four species are new: Idiognathodus crassadens, I. ignisitus, Neognathodus intrala , and Hindeodus calcarus. Two of these new species, N. intrala and I. crassadens , together with I. robustus , define an assemblage zone that allows correlation of the marine portion of the Lower Kittanning cyclothem across North America.

Abstract Late Pennsylvanian conodont faunas were dominated by idiognathodids historically assigned to Idiognathodus (flat P 1 ) or Streptognathodus (troughed P 1 ). Recent work suggests clades arose iteratively, through time, from unrelated ancestors in different geographical regions. The end-Desmoinesian extinction event terminated two major genera, Swadelina (troughed) and Neognathodus (long carina), and comparable new morphotypes developed from surviving Idiognathodus species in the early Kasimovian, especially in North America. True Streptognathodus (troughed) and Heckelina n. gen (asymmetric, eccentric groove) appeared in North America in the mid-Kasimovian. Another troughed clade arose in Eurasia (‘ S. ’ 2) and attained a global distribution by the late Kasimovian. A second, early Gzhelian, Eurasian radiation produced new troughed forms (‘ S. ’ 4) that dominated Gzhelian faunas globally. In South China, endemic clades of eccentrically grooved Idiognathodus ? and troughed forms (‘ S .’ 3) appeared in the late Kasimovian and persisted into the Gzhelian. Typical Idiognathodus species were uncommon by the late Kasimovian and disappeared in the mid-Gzhelian. After a low diversity interval in the mid-Gzhelian, a new major radiation of weakly troughed forms occurred (‘ S. ’ 5), which led to redevelopment of Idiognathodus -like elements in the Cisuralian. Other conodont genera from offshore ( Gondolella, Idioprioniodus ) and nearshore settings ( Hindeodus, Diplognathodus, Adetognathus, Ellisonia ) are poorly studied and show low diversity and little morphological change.