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New early Paleozoic Hyolithida and Orthothecida (Hyolitha) from North America
Published online by Cambridge University Press: 19 May 2016
Abstract
Reexamination of collections of North American Hyolitha reveals the presence of several new genera and several taxa previously known only from southeastern Europe and the Soviet Union. New representatives of the family Hyolithidae in North America are Doescherina clarki n. gen. and sp. from the Upper Cambrian of Montana and Grantitheca glenisteri n. gen. and sp. from the Lower Cambrian of New York. The geographic and stratigraphic ranges of Nevadotheca Malinky are extended by placement of Hyolithes excellens Billings from the Lower Cambrian of Newfoundland and H. princeps Billings from the Lower Cambrian of Quebec in that genus, and by the occurrence of the new species N. heckeli in the Upper Cambrian of Tennessee. Diversity within the Hyolithidae is further increased by the discovery of specimens representing a new genus in the Upper Cambrian of Alberta, but that genus remains indeterminate because those specimens are not well preserved.
The type lot of Hyolithes communis Billings from the Lower Cambrian of Quebec is here included under Nitoricornus Syssoiev, to which the species H. impar Ford from the Lower Cambrian of New York is also transferred. Morphology of specimens of Hyolithes quadricostatus Shaler and Foerste from the Lower Cambrian of Newfoundland requires placement under Holmitheca quadricostatus (Shaler and Foerste) and Novitatus mapesi n. sp., family Novitatidae, order Orthothecida. Formerly, Nitoricornus Syssoiev, Holmitheca Syssoiev, and Novitatus Syssoiev were known only from the Soviet Union. These occurrences extend their geographic ranges to North America. The first known representative of the family Pauxillitidae Marek in North America, Neopauxillites zlatarskii n. gen. and sp., extends the range of that family from the Ordovician of Czechoslovakia to the Lower Cambrian of Newfoundland.
Overall poor preservation of type specimens of Hyolithes americanus (Hall), H. gregarius (Meek and Hayden), H. primordialis (Hall), and H. welleri Roy precludes complete diagnoses of these species and confident assignment to genus. Hyolithes americanus and H. welleri are tentatively included under Grantitheca; the other species remain under Hyolithes with question. The names of these species should not be used for new material until better preserved topotypes become available for study.
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