Dean, Christopher D

Ewin, Timothy AM

Ford, Madeline

Thompson, Jeffrey

English

UCL Discovery

INTRODUCTION- Understanding biological and geological factors driving fossil preservation are crucial for understanding ancient biodiversity (Smith, 1994).- Despite this, large, global databases are rarely used in understanding taphonomic drivers and the conditions underlying fossil preservation.- We used the Palaeozoic fossil record of echinoids from museum specimens and the literature to analyse factors controlling specimen-level preservation.Taphonomic controls on the Palaeozoic echinoidJeffrey R. Thompson*, Christopher D. Dean, Madeline Ford, Timothy A. M. Ewin- Dataset comprises 2037 specimens from 8 families in over twenty museum collections and from the literature.- The taphonomic grade of specimen was scored using a semi-quantitative scheme from 1-5 as described below.- Associated age, grain size, lithology, and locality data was collected with each specimen (Thompson & Bottjer, 2019).- Statistical analyses were carried out in R, and include Chi Squared tests, analyses of Jaccard similarity, and Ordinal Logistic Regression to attempt to understand differences and drivers of differential taphonomy.MATERIALS AND METHODSACKNOWLEDGEMENTS AND REFERENCESThe authors thank the numerous museum collections managers and curators who provided access to specimens. This work has been funded by the Leverhulme Trust.Smith, A. B. (1994). Systematics and the fossil record: documenting evolutionary patterns. John Wiley & Sons.Thompson, J. R., & Bottjer, D. J. (2019). Quantitative analysis of substrate preference in Carboniferous stem group echinoids. Palaeogeography, Palaeoclimatology, Palaeoecology, 513, 35-51..State 1 State 2 State 3State 4 State 5- Disarticulated single plates or spines- Fragments of tests- Articulated or semi-articulated tests without spines- Articulated or semi-articulated tests with spines- Multiple disarticulated but associatedPlates.−6.2−4.0−2.0 0.0 2.0 4.0 7.2Pearsonresiduals:p−value =< 2.22e−16Preservation ScoreGrain size1Fine GrainedCoarse Grained2 3 4 5−5.1−4.0−2.0 0.0 2.0 4.0 4.8Pearsonresiduals:p−value =< 2.22e−16Preservation ScoreLithology1SiliciclasticCarbonate2 3 4 5Frequency0200400600800250300350400450Time (Ma)Preservation score54321TrPCDSODATA ANALYSIS AND RESULTSJaccard Similarity0.250.500.751.00300350400450Time (Ma)Test1v22v33v44v51v32v43v51v42v51v5PCDSOJaccard Similarity scores comparing taxonomic similarity between preservational typesPreservational types across time, taxon, and lithology01002003004005006001 2 3 4 5Preservation ScoreFrequencyFamilyArchaeocidaridaeEchinocystitidaeLepidesthidaeLepidocentridaeMiocidaridaePalaechinidaeProterocidaridaeStem_Echinoidea01002003004005001 2 3 4 5Preservation ScoreFrequency Grain sizeCoarse GrainedFine GrainedChi squared tests comparing distribution of states across grain size and lithologyCONCLUSIONS- Preservation of Palaeozoic echinoids varies by taxon, age, lithology and grain size.- Better preservation is found in fine-grained rocks.- Grainsize and lithology predict preservational types.Ordinal Logistic Regression *j.r.thompson@soton.ac.ukfossil record

Taphonomic controls on the Palaeozoic echinoid fossil record

https://discovery.ucl.ac.uk/id/eprint/10159784/1/GSA_2022_Poster_J_Thompson_CD_EDITS%5B5%5D%20%20-%20%20Read-Only.pdf

Taphonomic controls on the Palaeozoic echinoid fossil record

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