Palaeogeographic distribution and diversity of cephalopods during the Cambrian–Ordovician transition

Fang, Xiang; Kröger, Björn; Zhang, Yuandong; Zhang, Yunbai; Chen, Tingen

doi:10.1016/j.palwor.2018.08.007

Cited by 13 publications

(13 citation statements)

References 28 publications

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“…The gaps separating the pseudoduplicates are between 10 and 14 my, except for E. primus , which occurs in the time interval directly prior to Ectenolites clelandi . The latter is still included because the genus is thought to be one of the few genera to survive the Cambrian–Ordovician boundary [ 51 , 99 ]. Thus, the criteria for the inclusion of pseudoduplicates were either the long range of a genus and corresponding gaps between template and pseudoduplicate species, or the significance of a genus surviving a particular time interval.…”

Section: Methodsmentioning

confidence: 99%

Early cephalopod evolution clarified through Bayesian phylogenetic inference

et al. 2022

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Background Despite the excellent fossil record of cephalopods, their early evolution is poorly understood. Different, partly incompatible phylogenetic hypotheses have been proposed in the past, which reflected individual author’s opinions on the importance of certain characters but were not based on thorough cladistic analyses. At the same time, methods of phylogenetic inference have undergone substantial improvements. For fossil datasets, which typically only include morphological data, Bayesian inference and in particular the introduction of the fossilized birth-death model have opened new possibilities. Nevertheless, many tree topologies recovered from these new methods reflect large uncertainties, which have led to discussions on how to best summarize the information contained in the posterior set of trees. Results We present a large, newly compiled morphological character matrix of Cambrian and Ordovician cephalopods to conduct a comprehensive phylogenetic analysis and resolve existing controversies. Our results recover three major monophyletic groups, which correspond to the previously recognized Endoceratoidea, Multiceratoidea, and Orthoceratoidea, though comprising slightly different taxa. In addition, many Cambrian and Early Ordovician representatives of the Ellesmerocerida and Plectronocerida were recovered near the root. The Ellesmerocerida is para- and polyphyletic, with some of its members recovered among the Multiceratoidea and early Endoceratoidea. These relationships are robust against modifications of the dataset. While our trees initially seem to reflect large uncertainties, these are mainly a consequence of the way clade support is measured. We show that clade posterior probabilities and tree similarity metrics often underestimate congruence between trees, especially if wildcard taxa are involved. Conclusions Our results provide important insights into the earliest evolution of cephalopods and clarify evolutionary pathways. We provide a classification scheme that is based on a robust phylogenetic analysis. Moreover, we provide some general insights on the application of Bayesian phylogenetic inference on morphological datasets. We support earlier findings that quartet similarity metrics should be preferred over the Robinson-Foulds distance when higher-level phylogenetic relationships are of interest and propose that using a posteriori pruned maximum clade credibility trees help in assessing support for phylogenetic relationships among a set of relevant taxa, because they provide clade support values that better reflect the phylogenetic signal.

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Section: Methodsmentioning

confidence: 99%

Early cephalopod evolution clarified through Bayesian phylogenetic inference

et al. 2022

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“…Most authors consider members of the order Plectronocerida to represent the oldest undoubted cephalopods 2 , 5 , 6 , with the mid late Cambrian Plectronoceras cambria 7 as the oldest representative 8 , 9 . In members of late Cambrian Ellesmerocerida, the shell is divided into chambers by concave-shaped septa, and the siphuncle is relatively wide and located marginally along the ventral side of the phragmocone 10 .…”

Section: Introductionmentioning

confidence: 99%

“…Abbreviations: Fm Formation, SSFs Small Shelly Fossils. Family range chart from Fang et al 8 . Stratigraphy from Hutchinson 11 , Landing et al 15 , King 18 , and McCartney 83 .…”

Section: Introductionmentioning

confidence: 99%

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A potential cephalopod from the early Cambrian of eastern Newfoundland, Canada

et al. 2021

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Although an early Cambrian origin of cephalopods has been suggested by molecular studies, no unequivocal fossil evidence has yet been presented. Septate shells collected from shallow-marine limestone of the lower Cambrian (upper Terreneuvian, c. 522 Ma) Bonavista Formation of southeastern Newfoundland, Canada, are here interpreted as straight, elongate conical cephalopod phragmocones. The material documented here may push the origin of cephalopods back in time by about 30 Ma to an unexpected early stage of the Cambrian biotic radiation of metazoans, i.e. before the first occurrence of euarthropods.

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“…The stratigraphically earliest records of fossil cephalopods represented by Plectronoceras cambria and a few other species are from the Uppermost Cambrian of North China (Walcott 1905;Kröger and Zhang 2009;Kröger 2013;Fang et al 2019a). After near-extinction at the end of the Cambrian, cephalopods underwent significant diversification and palaeogeographical differentiation during the Ordovician and experienced another extinction period at the end of the Ordovician (Frey et al 2004;Kröger and Zhang 2009;Kröger 2013;Fang et al 2019b).…”

Section: Introductionmentioning

confidence: 99%

Evolution of Ordovician cephalopod diversity in the Middle Yangtze region of South China and its controlling factors

Song

Xiao

2020

Arab J Geosci

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The evolution of Ordovician cephalopod diversity in the Middle Yangtze region of South China has been analysed. The cephalopods in this region appeared in the earliest Tremadocian, radiated in the Early-Middle Floian and Middle Ordovician, and went through an extinction period during the Late Katian and Hirnantian. The composition of the cephalopod fauna underwent major changes in the Late Floian. Specifically, all the genera occurring in previous time periods disappeared and Tarphyceratida, Actinoceratida, and Orthoceratida appeared and prospered. Differences in the evolution of cephalopod diversity between Middle Yangtze region and other regions were detected, which were caused by differences in the vertical sequence and horizontal combination of controlling factors. Changes in living environments and the distribution of food resources prompted Ordovician cephalopods to evolve adaptations for life in deep-water environments. The low-temperature ocean current near the western coastline of Gondwana created favourable conditions for the Floian peak of cephalopod diversity in South China. The tectonic movements, high rainfall, and relatively closed environment of the Middle Yangtze region led to rapid sea level rise and hindered cephalopod diversification. These processes explain the low cephalopod diversity in the Late Ordovician and the absence of the previously reported Katian radiation peak in this region.

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Palaeogeographic distribution and diversity of cephalopods during the Cambrian–Ordovician transition

Cited by 13 publications

References 28 publications

Early cephalopod evolution clarified through Bayesian phylogenetic inference

Early cephalopod evolution clarified through Bayesian phylogenetic inference

A potential cephalopod from the early Cambrian of eastern Newfoundland, Canada

Evolution of Ordovician cephalopod diversity in the Middle Yangtze region of South China and its controlling factors

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