Trilobite fauna (Wuliuan Stage, Miaolingian Series, Cambrian) of the lower Lakeview Limestone, Pend Oreille Lake, Idaho

Abstract

The Lakeview Limestone is one of the westernmost Cambrian exposures in the northwestern United States and occurs on the western edge of the Montania paleotopographic high. These deposits occur between the deeper water deposits to the west and carbonate banks and intracratonic basins to the east and provide critical link between the regions. A re-investigation of the Cambrian trilobite faunas from the lower portion of the Lakeview Limestone, Pend Oreille Lake, Idaho, is undertaken due to the inadequate illustrations and descriptions provided by Resser (1938a). Resser's type specimens and additional material are figured and described. The trilobite assemblages represent the Ptychagnostus praecurrens Zone, Wuliuan Stage, Miaolingian Series and including two new taxa: Itagnostus idahoensis n. sp., and Utia debra n. sp. Because of the similarity between some species of Amecephalus from the Lakeview Limestone to specimens from the Chisholm Shale, Nevada, the type specimens of Amecephalus piochensis (Walcott, 1886) and Am. packi (Resser, 1935), Walcott's and Resser's type specimens are re-illustrate and their taxonomic problems are discussed. Utia curio Walcott, 1924 from the Spence Shale, Utah, have never been re-illustrated since Walcott (1925), these type specimens are also re-illustrated and compared to Utia debra n. sp.UUID: http://zoobank.org/5ef6ee5e-bddc-4395-becf-9bcea54c679c

Cambrian trilobites from theGlossopleura walcottiZone (Miaolingian Series, Wuliuan Stage) of Mendoza, western Argentina

“…), and a less-distinct indentation on the rear pygidial margin, and by lacking well-defined eye ridges and pygidial border furrow (Lochman in Cooper et al, 1952, p. 128; see also Kobayashi, 1942; Rasetti, 1951; Poulsen, 1964; Peel, 2021). Lochman in Cooper et al (1952), Palmer (1954), and Poulsen in Moore (1959) provided emended diagnoses of Athabaskia , which have been largely accepted by subsequent authors (Robison and Babcock, 2011; Bordonaro, 2014; Sundberg, 2020).…”

“…The Glossopleura walcotti Zone .—This North American polymerid zone is well represented in North Greenland, eastern and western Canada, northern Idaho, Montana, Wyoming, the Great Basin, Arizona, Sonora, and the Appalachians (e.g., Holland, 1971 and multiple references therein; Robison, 1976; Palmer and Halley, 1979; Babcock, 1994; McCollum and Sundberg, 2007; Southworth et al, 2008; Foster, 2011; Rowland, 2011; Sundberg, 2011a, 2018, 2020; Taylor et al, 2012; Cuen-Romero et al, 2018; Peel, 2021, among many others). Glossopleura is an especially important member of the assemblage, constituting a valuable guide genus in restricted facies and open-shelf deposits at the platform margin.…”

“…Oryctocephalites reynoldsi is another valuable index in the fauna studied. As revised by Sundberg (2020), this species has been described from the Glossopleura walcotti and Ehmaniella zones of the Stephen Formation, Canadian Rocky Mountains (Rasetti, 1951; Whittington, 1995), from the Ptychagnostus praecurrens Zone (a partial equivalent of the G . walcotti Zone) of the lower Lakeview Limestone of Pend Oreille Lake, Idaho (Resser, 1938a; Sundberg, 2020), as well as from the G .…”

“…As revised by Sundberg (2020), this species has been described from the Glossopleura walcotti and Ehmaniella zones of the Stephen Formation, Canadian Rocky Mountains (Rasetti, 1951; Whittington, 1995), from the Ptychagnostus praecurrens Zone (a partial equivalent of the G . walcotti Zone) of the lower Lakeview Limestone of Pend Oreille Lake, Idaho (Resser, 1938a; Sundberg, 2020), as well as from the G . walcotti Zone of the Spence Shale of southeastern Idaho and Wellsville Mountains, northern Utah (Resser, 1939a; Campbell, 1974; Robison et al, 2015; Kimmig et al, 2019).…”

“…31, figs. 1–3; Sundberg, 2020, fig. 11.1–11.23), has a proportionately long pigaxis and a narrow pygidial border, like those of A .…”