RESEARCH METHODS Samples from the Dakota Formation were obtained from cores at Sergeant Bluff, Iowa (Witzke and Ludvigson, 1994). Samples from the Swan River Formation of Manitoba were obtained from unit 1 of outcrop section 57 of McNeil and Caldwell (1981, p. 349-350). Samples were impregnated with epoxy, and thin slabs and thin sections were cut perpendicular to bedding. Powdered

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The Upper Devonian–Lower Mississippian sequence in the subsurface of north-central Iowa and southeastern Nebraska consists of the Lime Creek, undifferentiated Sheffield–Maple Mill, English River, Prospect Hill, and Chapin Formations. The Lime Creek is restricted entirely to the Polygnathus biofacies where conodonts are present and correlates with an interval from Zone 4b to Faunal Interval 8 of the Canadian (Alberta) Rockies zonation based on conodonts and foraminifers. The oldest identifiable Famennian units range in age from the crepida–rhomboidea Zones at locality 1 to the Upper marginifera Zone or younger at localities 2 and 3. The youngest Devonian strata may occur in the Upper expansa Zone at locality 1 and Middle expansa Zone at localities 2 and 3. Famennian faunas are present in the Polygnathus biofacies at localities 1 and 3 and in the Icriodus biofacies at locality 2. A total of 50 species and subspecies are identified, four of which have not been previously described (Icriodus sp. A, Hemilistrona sp. A, Polygnathus depressus n. sp., and Polygnathus sp. B).

Upper Devonian (Famennian) sequences were sampled at two sections in the Canning Basin, Western Australia, and a section at Bactrian Mountain, Nevada, over an interval ranging from the Upper crepida Zone into the Lower marginifera Zone of the standard conodont zonation for the Famennian. Over 30,000 conodont elements have been identified among 43 species and subspecies within six genera. New complete and partial multielement reconstructions are illustrated for: Palmatolepis falcata, P. glabra prima, P. loba, P. minuta minuta, P. perlobata perlobata, P. perlobata maxima, P. quadrantinodosalobata, P. rhomboidea, P. schindewolfi, P. subgracilis, P. wolskae, Polygnathus cf. P. diversus, P. glaber glaber, P. nodocostatus nodocostatus, P. subnormalis, and P. cf. P. triphyllatus. The reconstructions are based on stratigraphic occurrence, detailed morphologic similarities, and a few exceptional low-diversity faunas. Additionally, Palmatolepis adamantea n. sp. is proposed based on the Pa element.A more precise understanding of the taxonomic boundaries of Palmatolepis is achieved through knowledge of the entire apparatus, rather than confined to the Pa elements. Reconstructions presented here provide a more comprehensive understanding of the range of morphologic variation that exists in Palmatolepis, and show that a single generalized elemental plan can be demonstrated for all members of the genus. The differences in the non-Pa elements can thus be used to refine taxonomy and increase understanding of phylogenetic relationships at the specific and subspecific level.