Upper Steptoean (Upper Cambrian) Trilobites from the Mckay Group of Southeastern British Columbia, Canada

Chatterton, Brian D. E.; Ludvigsen, Rolf

doi:10.1017/s0022336000059941

Cited by 28 publications

(132 citation statements)

References 33 publications

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“…The Olenidae was included in the Order Oleninae with another eleven families by Adrain (). Species representing seven of these families were chosen as outgroup: Andrarina costata (Angelin ) (Andrarinidae), Aphelaspis australis Henderson 1976 (Aphelaspididae), Asaphiscus wheeleri Meek (Asaphiscidae), Cedaria minor (Walcott ) (Cedariidae), Dokimocephalus pernasutus (Walcott ) (Dokimocephalidae), Orygmaspis contracta (Frederickson ) (Parabolinoididae) and Pterocephalia norfordi Chatterton & Ludvigsen (Pterocephaliidae). The unavailability of photographs and descriptions that allow coding of most of the proposed characters prevented the inclusion of representatives of the other four families.…”

Section: Methodsmentioning

confidence: 99%

First cladistic analysis of the trilobite family Olenidae from the Furongian and Ordovician

Monti

Confalonieri

2019

LET

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The Olenidae stands out for its abundance and biostratigraphical importance, especially in the Lower Palaeozoic rocks of northwestern Argentina. Their phylogenetic relationships have been traditionally determined stratigraphically and by direct morphological comparison. This study reports the first formal phylogenetic analysis of olenids. Eighty‐six characters (24 quantitative and 62 qualitative) were coded for 65 taxa (58 olenids). Quantitative characters were treated both as discrete and as continuous variables. To explore the best way of character coding for this group, continuous characters were coded as: median, log‐median, normalized and rescaled. Maximum parsimony and implied weighting were used as optimality criteria. A phylogenetic hypothesis more consistent with traditional taxonomy was reconstructed with both quantitative and qualitative partitions. All the trees obtained with quantitative characters coded as continuous and rescaled are better resolved, and those topologies were more similar among them. This treatment also reflects more effectively the behaviour of the original variables. Olenidae is not a monophyletic clade: Andrarina costata and Aphelaspis australis are included within the ingroup, as sister clade of Olenus gibbosus. Also, the results suggest that members of the Hypermecaspidinae constitute a new family within the Order Olenida. The traditional taxonomic scheme at subfamily level is partially supported. Triarthrinae and ‘pelturinds’ are recovered as monophyletic clades, but Oleninae is polyphyletic. This study proves, through a formal cladistic analysis, that characters disregarded by traditional taxonomy can be uncovered. Finally, this is the first step towards achieving a classification of the Olenidae taking into account the evolutionary process involved in its diversification history.

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Section: Methodsmentioning

confidence: 99%

First cladistic analysis of the trilobite family Olenidae from the Furongian and Ordovician

Monti

Confalonieri

2019

LET

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“…Originally, three stages were proposed (Ludvigsen & Westrop ), and their application was followed by a number of workers (e.g. Westrop ; Pratt ; Babcock ; Chatterton & Ludvigsen ; Saltzman et al . ).…”

Section: Cambrian Biostratigraphymentioning

confidence: 99%

“…Originally, three stages were proposed (Ludvigsen & Westrop 1985), and their application was followed by a number of workers (e.g. Westrop 1986;Pratt 1992;Babcock 1994a;Chatterton & Ludvigsen 1998;Saltzman et al 2000). Palmer (1998) extended the concept of a (mostly) biomerebased sub-division of the Cambrian to the entire system.…”

Section: Development Of Modern Trilobite Biostratigraphymentioning

confidence: 99%

Cambrian trilobite biostratigraphy and its role in developing an integrated history of the Earth system

Babcock

Shanchi

Ahlberg

2017

LET

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One of the principal biostratigraphical tools used in the lower Palaeozoic, and especially the Cambrian System, is trilobites. Historically, both polymerids and agnostoids have commonly been included as ‘trilobite’ groups, although currently the question of whether they comprise a monophyletic group or are polyphyletic is unsettled. Beginning in the late 1800s, the base of the Cambrian System was marked by the lowest occurrence of olenelline trilobites. Discovery of a rich pre‐trilobite metazoan record in the mid‐1900s led to significant modification of that concept, but polymerids and especially agnostoids still rank among the leading biostratigraphical and chronostratigraphical guides through much of the Cambrian. Chronostratigraphical sub‐division of the trilobite‐bearing part of the Cambrian System derives largely from biostratigraphical, ecological and evolutionary concepts about agnostoids and polymerids introduced in the 1940s to 1970s by A.H. Westergård, A.R. Palmer and R.A. Robison. Westergård introduced a zonation for Scandinavia that was largely based on agnostoids. Palmer explained the distribution of Cambrian trilobite faunas in terms of restricted and unrestricted access to open oceans. Together, these ideas coalesced in Robison's recognition of separate zonation schemes for restricted‐shelf polymerids, open‐shelf polymerids and open‐shelf (cosmopolitan) agnostoids. Palmer also introduced the concept of biomeres, which placed sharp limits on biostratigraphical intervals recognizable from trilobites. Global correlation in the upper half of the Cambrian today depends to a large extent on the ranges of agnostoids and some polymerids characteristic of open‐shelf to slope areas, ones that facilitate identification of precise intercontinental tie points. Agnostoid and polymerid biostratigraphy is now being integrated with information about coastal onlap and eustatic sea‐level history, geochemical cycling and other data to provide a more complete understanding of the early Palaeozoic biosphere and its complex physico‐chemical context.

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“…However, apparently there was insufficient calcite in the Kaili sediment so that the secondary calcite did not accrete to form calcite nodules nucleated around the trilobites, such as the trilobite nodules from the late Cambrian (Furongian) Wujiajiania sutherlandi Fauna near Tanglefoot Creek, British Columbia (Chatterton & Ludvigsen 1998).…”

Section: Preservation Of Kaili Trilobitesmentioning

confidence: 99%

Preservation of the gastrointestinal system in Olenoides (Trilobita) from the Kaili Biota (Cambrian) of Guizhou, China

2007

Alcheringa: An Australasian J. of Palaeontology

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Upper Steptoean (Upper Cambrian) Trilobites from the Mckay Group of Southeastern British Columbia, Canada

Cited by 28 publications

References 33 publications

First cladistic analysis of the trilobite family Olenidae from the Furongian and Ordovician

First cladistic analysis of the trilobite family Olenidae from the Furongian and Ordovician

Cambrian trilobite biostratigraphy and its role in developing an integrated history of the Earth system

Preservation of the gastrointestinal system in Olenoides (Trilobita) from the Kaili Biota (Cambrian) of Guizhou, China

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