Ptychopariid Trilobites of the Lower-Middle Cambrian Boundary Interval, Pioche Shale, Southeastern Nevada

Sundberg, Frederick A.; McCollum, Linda B.

doi:10.1666/0022-3360(2000)074<0604:ptotlm>2.0.co;2

Cited by 39 publications

(70 citation statements)

References 11 publications

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“…The Emigrant Formation is only 14% the thickness of equivalent-age strata in the ~3000 m thick shelf section in the House Range, Utah (Hintze, 1988; Hintze and Kowallis, 2009) and the 3050 m thick shelf section in the Toano Range near Wendover, Nevada (McCollum and Miller, 1991). The lower member of the Emigrant Formation ranges only from 7–9% of thickness of sections in the Inyo Mountains, California; Groom Range, Oak Spring Summit, Desert Range, Toano Range, Nevada; and Wah Wah Mountains, House Range, and Drum Mountains, Utah (data from Merriam, 1964; Ross, 1965; Barnes and Christiansen, 1967; Palmer and Halley, 1979; Dommer, 1980; Rees, 1986; Sundberg, 1990, 1991, 1994, 2011; McCollum and Miller, 1991; Osleger et al, 1996; Sundberg and McCollum, 1997, 2000, 2003a; Hintze and Kowallis, 2009; McCollum and McCollum, 2011; Miller et al, 2012). However, these percentages are relatively high as a result of these shelfal sections not having detailed biostratigraphy in the lower portions.…”

Section: Stratigraphic and Paleogeographic Settingmentioning

confidence: 99%

“…13, 15; species reassigned by Sundberg, 2004) and M . robusta Sundberg and McCollum, 2000 (fig. 13).…”

Section: Systematic Paleontologymentioning

confidence: 99%

“…granulata Eddy and McCollum, 1998 [ M . antelopea Sundberg and McCollum, 2000, is excluded here due to its placement outside the Mexicella clade; see Sundberg, 2004]), there are several similarities between the two genera, including the shape and convexity of the cranidia and glabella, generally obscure glabellar furrows, downsloping of the preglabellar area, parallel to slightly convergent anterior facial sutures, and weak expression of the eye ridges. Achlysopsis differs in having a slightly deeper anterior border and palpebral lobe furrows, larger and generally more posteriorly located palpebral lobes, and generally lacking a boss on the preglabellar field.…”

Section: Systematic Paleontologymentioning

confidence: 99%

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Trilobite biostratigraphy of the Cambrian 5 and Drumian stages, Series 3 (Laurentian Delamaran, Topazan, and Marjuman stages, Lincolnian Series) of the lower Emigrant Formation at Clayton Ridge, Esmeralda County, Nevada

Sundberg¹

2018

J. Paleontol.

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The Emigrant Formation at Clayton Ridge, Nevada, consists of 420 m of variably interbedded shale, siltstone, and limestone representing an outer shelf environment. It ranges in age from the youngest portion of the Dyeran Stage (Laurentian Waucoban Series; Cambrian Stage 4, Series 2) to Skullrockian Stage (Ibexian Series; Tremadocian Stage, Lower Ordovician). Consequently, it is condensed compared to other localities. For example, the age-equivalent succession in the House Range and the Wendover Range of Utah and Nevada, respectively, is seven times thicker.The 100 m thick lower limestone and siltstone member of the Emigrant Formation at Clayton Ridge ranges in age from the Bolbolenellus euryparia/Nephrolenellus multinodus Zone (Laurentian Dyeran Stage) to the Cedaria brevifrons Zone (Laurentian Marjuman Stage; Drumian Stage; this study). The 40 trilobites described herein from two closely spaced sections of the lower member belong to the Glossopleura walcotti/Ptychagnostus praecurrens Zone (Laurentian Delamaran Stage; Stage 5), Ehmaniella Zone (Laurentian Topazan Stage; Stage 5), and Cedaria selwyni to C. brevifrons zones (Laurentian Marjuman Stage; Drumian Stage) zones. The lower Emigrant Formation is <10% as thick as age-equivalent age strata elsewhere in Nevada, California, and Utah. This condensed nature of the lower Emigrant Formation began with the flooding event at the beginning of the Oryctocephalus indicus biochron and the subsequent build-ups of the thick carbonate platforms to the south and northeast.New species are Pagetia aspinosa, P. claytonensis, and Syspacephalus mccollumorum.

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Section: Stratigraphic and Paleogeographic Settingmentioning

confidence: 99%

“…13, 15; species reassigned by Sundberg, 2004) and M . robusta Sundberg and McCollum, 2000 (fig. 13).…”

Section: Systematic Paleontologymentioning

confidence: 99%

Section: Systematic Paleontologymentioning

confidence: 99%

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Trilobite biostratigraphy of the Cambrian 5 and Drumian stages, Series 3 (Laurentian Delamaran, Topazan, and Marjuman stages, Lincolnian Series) of the lower Emigrant Formation at Clayton Ridge, Esmeralda County, Nevada

Sundberg¹

2018

J. Paleontol.

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“…We use as a case study Crassifimbra? metalaspis (Sundberg and McCollum 2000), an early ptychoparioid trilobite from the uppermost Dyeran (traditional Laurentian ''Lower Cambrian'') Pioche Formation of Nevada (Webster in press). Early ptychoparioid trilobites are thought to be the plesiomorphic ancestral stock from which more derived trilobite clades arose (Fortey in Whittington et al 1997, p. 296;Fortey 2001Fortey , p. 1148) and thus occupy a pivotal place in trilobite evolution.…”

Section: Introductionmentioning

confidence: 99%

Modularity of a Cambrian ptychoparioid trilobite cranidium

Webster

Zelditch

2011

Evolution &Amp; Development

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Modularity of the cranidium of Crassifimbra? metalaspis, a Cambrian ptychoparioid trilobite, is investigated using landmark-based geometric morphometric methods to gain insight into the integration among morphogenetic processes responsible for shaping the head of an ancient arthropod. Of particular interest is the extent to which the structure of phenotypic integration was governed by direct interactions among developmental pathways, because these interactions may generate long-term constraints on evolutionary innovation. A modified two-way ANOVA decomposes cranidial shape variation into components representing symmetric variation among individuals and fluctuating asymmetry (FA). The structure of integration of each of these components is inferred from correlated deviations in shape among nine partitions of the cranidium. Significant correlation among partitions in FA indicates direct interactions among their respective developmental pathways. An a priori hypothesis that modularity was determined by functional association among partitions is not well supported by the among-partition correlation structure for either component of variation. Instead, exploratory analyses reveal that phenotypic integration was strongly influenced by spatially localized morphogenetic controls. Comparison of the structures of the Individuals and FA components of variation reveals that the two share relatively few commonalities: the structure of phenotypic integration was only weakly influenced by direct interactions. The large contribution of parallel variation to phenotypic integration suggests that modularity was unlikely to have imposed a long-term constraint on evolutionary innovation in these early trilobites.

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“…The diagnosis has been modified from Sundberg and McCollum (2000) to encompass the taxa from the Lakeview Limestone.…”

Section: Systematic Paleontologymentioning

confidence: 99%

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

Sundberg

2020

J. Paleontol.

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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

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Ptychopariid Trilobites of the Lower-Middle Cambrian Boundary Interval, Pioche Shale, Southeastern Nevada

Cited by 39 publications

References 11 publications

Trilobite biostratigraphy of the Cambrian 5 and Drumian stages, Series 3 (Laurentian Delamaran, Topazan, and Marjuman stages, Lincolnian Series) of the lower Emigrant Formation at Clayton Ridge, Esmeralda County, Nevada

Trilobite biostratigraphy of the Cambrian 5 and Drumian stages, Series 3 (Laurentian Delamaran, Topazan, and Marjuman stages, Lincolnian Series) of the lower Emigrant Formation at Clayton Ridge, Esmeralda County, Nevada

Modularity of a Cambrian ptychoparioid trilobite cranidium

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

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