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The Mosasaur Fossil Record Through the Lens of Fossil Completeness

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The Mosasaur Fossil Record Through the Lens of Fossil Completeness This is a repository copy of The Mosasaur Fossil Record Through the Lens of Fossil Completeness. White Rose Research Online URL for this paper: http://eprints.whiterose.ac.uk/130080/ Version: Accepted Version Article: Driscoll, DA, Dunhill, AM orcid.org/0000-0002-8680-9163, Stubbs, TL et al. (1 more author) (2018) The Mosasaur Fossil Record Through the Lens of Fossil Completeness. Palaeontology, 62 (1). pp. 51-75. ISSN 0031-0239 https://doi.org/10.1111/pala.12381 © 2018 The Palaeontological Association This is the peer reviewed version of the following article: Driscoll, DA, Dunhill, AM, Stubbs, TL et al. (2018) The Mosasaur Fossil Record Through the Lens of Fossil Completeness. Palaeontology. ISSN 0031-0239, which has been published in final form at https://doi.org/10.1111/pala.12381. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. 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[email protected] https://eprints.whiterose.ac.uk/ Palaeontology THE MOSASAUR FOSSIL RECORD THROUGH THE LENS OF FOSSIL COMPLETENESS Journal: Palaeontology Manuscript ID PALA-01-18-4136-OA.R1 Manuscript T pe: Original Article Date Submitted b the Author: n/a Complete List of Authors: Driscoll, Daniel, -ni.erist of /ristol, 0arth Sciences Dunhill, Ale1, -ni.ersit of Leeds, School of 0arth and 0n.ironment Stubbs, Thomas, -ni.ersit of /ristol, 0arth Sciences /enton, Michael, -ni.ersit of /ristol, School of 0arth Sciences marine reptiles, fossil record 4ualit , sea le.el, palaeodi.ersit , mosasaur, 2e 3ords: fossil completeness Palaeontology Page 1 of 114 Palaeontology Driscoll 1 1 2 3 1 THE MOSASAUR FOSSIL RECORD THROUGH THE LENS OF FOSSIL 4 5 2 COMPLETENESS 6 7 1 2 1 8 3 by DANIEL A. DRISCOLL , ALEXANDER M. DUNHILL , THOMAS L. STUBBS and 9 10 4 MICHAEL J. BENTON1 11 12 5 1School of Earth Sciences, University of Bristol, Wills Memorial Building, Queen’s Road, 13 14 6 Bristol BS8 1RJ, U.K. [email protected], [email protected], 15 16 7 2School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, U.K. 17 18 19 8 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Palaeontology Palaeontology Page 2 of 114 Driscoll 2 1 2 3 9 Abstract. The quality of the fossil record affects our understanding of macroevolutionary 4 5 10 patterns. Palaeodiversity is filtered through geological and human processes, and efforts to 6 7 11 correct for these biases are part of a debate concerning the role of sampling proxies and 8 9 12 standardisation in models of biodiversity. Here, we analyse the fossil record of mosasaurs in 10 11 13 terms of fossil completeness as a measure of fossil quality, using three novel metrics of fossil 12 13 14 14 completeness with a compilation of 4,083 specimens. All metrics correlate with each other. A 15 16 15 new qualitative measure of character completeness (QCM), correlates with the phylogenetic 17 18 16 character completeness metric. Mean completeness by species decreases with specimen count, 19 20 17 and average completeness by substage varies significantly. Mean specimen completeness is 21 22 18 higher for species-named fossi s than those identified to genus and fami y. The effect of 23 24 19 tooth-on y specimens is ana ysed. Important y, 8e find that comp eteness of species does not 25 26 27 20 corre ate 8ith comp eteness of specimens. Comp eteness varies 2y pa aeogeography, North 28 29 21 American specimens sho8ing higher comp eteness than those from Eurasia and Gond8ana. 30 31 22 These metrics can 2e used to identify e7ceptiona preservation, 8ith specimen comp eteness 32 33 23 varying significant y 2y 2oth formation and itho ogy. The Be gian Cip y Formation disp ays 34 35 24 the highest comp eteness, and c ay itho ogies sho8 higher comp eteness va ues than others. 36 37 25 Neither species diversity nor sea eve corre ates significant y 8ith fossi comp eteness. A 38 39 40 26 GLS ana ysis using mu tip e varia2 es agrees 8ith this resu t. Ho8ever, GLS sho8s that t8o 41 42 27 varia2 es have significant predictive va ue for mode ing averaged diversity, name y sea eve 43 44 28 and mosasaur- and p esiosaur-2earing formations, the atter of 8hich is redundant 8ith 45 46 29 diversity. Mosasaur comp eteness is not driven 2y sea eve , nor does comp eteness imit the 47 48 30 mosasaur diversity signa . 49 50 31 51 52 32 Key words: marine repti es, mosasaur, fossi record 5ua ity, fossi comp eteness, sea eve , 53 54 55 33 pa aeodiversity. 56 57 58 59 60 Palaeontology Page 3 of 114 Palaeontology Driscoll 3 1 2 3 34 MOSASAURIDAE 8as a re ative y short- ived, 2ut diverse and a2undant c ade of marine 4 5 35 s5uamates that radiated in Late Cretaceous epicontinenta seas and died out at the 0/Pg 6 7 36 2oundary (De2raga & Carro 1443). The rise of mosasaurids (ca ed Amosasaurs. throughout 8 9 37 the paper) fo o8ed dramatic changes in the marine repti e fauna (Stub2s & Benton 2016), 10 11 38 inc uding decreases in disparity of p esiosaurs in the Late Jurassic (Benson & Druc3enmi er 12 13 14 39 2014) as 8e as the e7tinction of cryptoc idid p esiosaurs, ichthyosaurs (Bardet 1444, Fisher 15 16 40 et al. 2012) and tha attosuchian crocodi es (Coung et al. 2010) in the Ear y to mid- 17 18 41 Cretaceous. Mosasauroids (aigia osaurids and do ichosaurids) arose in the Cenomanian as 19 20 42 re ative y sma s8imming repti es, fo o8ed 2y true mosasaurs in the Turonian (Bardet et al. 21 22 43 2008). As in other groups of marine repti es (Massare 1444), the Mosasauridae sho8ed 23 24 44 increasing adaptations to the marine environment through time (Motani 2004). The average 25 26 27 45 2ody siDe of mosasaurs increased through the Late Cretaceous, from 1E2 m in ear y semi- 28 29 46 terrestria forms, to a gigantic 14E17 m in ater forms (Po cyn et al. 2014G Stub2s & Benton 30 31 47 2016). They 2ecame increasing y efficient s8immers and fi ed niches vacated 2y some of the 32 33 48 aforementioned pe agic marine predators after their e7tinction (Motani 2005G Lindgren et al. 34 35 49 2007, 2004, 2011, 2013G Houssaye et al. 2013). Mosasaurs thrived in many marine 36 37 50 environments (0iernan 2002), from roc3y shores to pe agic she ves, inc uding fresh 8ater 38 39 40 51 environments (Ho mes et al. 1444), and 2y the atest Cretaceous, they 8ere the ape7 predators 41 42 52 in many comp e7 ocean ecosystems (SIrensen et al. 2013). According y, mosasaur fossi s 43 44 53 have a 8idespread stratigraphic and g oba geographic distri2ution in a variety of 45 46 54 itho ogica y distinct Upper Cretaceous marine formations (Russe 1467). 47 48 55 Marine repti es have figured in severa studies that have contri2uted to the de2ate a2out 49 50 56 ho8 to address 2iases in the fossi record (e.g. Benson et al. 2010G Benson & But er 2011G 51 52 57 C eary et al. 2015G Tutin and But er 2017). Does the fossi record provide a reasona2 e picture 53 54 55 58 of mosasaur evo ution (Po cyn et al. 2014), or is the record substantia y 2iased 2y the 56 57 58 59 60 Palaeontology Palaeontology Page 4 of 114 Driscoll 4 1 2 3 59 idiosyncrasies of preservation and co ection (Benson et al. 2010G Benson & But er 2011)J 4 5 60 Benson et al. (2010) identified serious mega2iases affecting a Cretaceous marine repti es, 6 7 61 inc uding mosasaurs, and argued that their pa aeodiversity signa 8as dependent on 8 9 62 geo ogica samp ing 2iases, meaning that the ra8 data said itt e a2out their true diversity. 10 11 63 Part of this resu t depended on residua diversity estimates using a method that has since 2een 12 13 14 64 severe y criticised (Dunhi et al. 2014, 2018G Broc3 ehurst 2015G Sa3amoto et al. 2017). Re- 15 16 65 ana ysis ed Benson and But er (2011) to identify that sha o8 marine tetrapods at east, 17 18 66 inc uding most mosasaurs, sho8ed c ose corre ation 2et8een diversity and sea eve and 19 20 67 continenta area. Benson and But er (2011) interpreted this as a Acommon cause. effect (Peters 21 22 68 2005), ana ogous to a species-area effectG the fossi record and pa aeodiversity of marine 23 24 69 repti es f uctuated simu taneous y as sea eve rose and fe .
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