Abstract Volume7th Swiss Geoscience MeetingNeuchâtel, 20th – 21st November 2009

6. Darwin, Evolution and Palaeontology

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gy 6. Darwin, Evolution and Palaeontology

Lionel Cavin

Schweizerische Paläontologische Gesellschaft (SPG/SPS), Kommission der Schweizerischen Paläontologischen Abhandlungen (KSPA), Swiss Commission of Palaeontology Award

6.1 BeckerD.,BergerJ.-P.,HiardF.,Menkveld-GfellerU.,MennecartB.&ScherlerL.:LateAquitanianmammalsfromtheEngehaldelocality(Bern,Switzerland)

6.2 BrühwilerT.,BucherH.,GoudemandN.,WareD.,HermannE.:Smithianammonoids(EarlyTriassic):explosiveevolu-tionaryradiationfollowingthePermian/Triassicmassextinction

6.3 Buffetaut,E.:Darwiniandinosaurs:missinglinksorevolutionaryfailures?

6.4 GiraultF.E.&ThiersteinH.R.:DiatomassemblageturnoverintheNW-Pacificatthe2.73Maclimatetransition

6.5 GiraultF.E.,WellerA.F.&ThiersteinH.R.:Neogeneglobalcooling:diatomsizevariabilityinachangingocean

6.6 GoudemandN.,OrchardM.,TafforeauP.,UrdyS.,BrühwilerT.,BucherH.,BrayardA.,GalfettiT.,MonnetC.,LebrunR.&ZollikoferC.:PaleobiologyofEarlyTriassicconodonts:implicationsofnewlydiscoveredfusedclustersimagedbyX-raysynchrotronmicrotomography

6.7 Klug C., Kröger B., Kiessling W., Mullins G.L., Servais T., Frýda J., Korn D. & Turner S.: The Devonian NektonRevolution

6.8 KlugC.,SchulzH.&DeBaetsK.:RedtrilobiteswithgreeneyesfromtheDevonianofMorocco

6.9 KlugC.,SchweigertG.,FuchsD.&DietlG.:Firstrecordofabelemnitepreservedwithbeaks,armsandinksacfromtheNusplingenLithographicLimestone(Kimmeridgian,SWGermany)

6.10 LavoyerT.,BertrandY.&BergerJ.-P.:Theborehole01983X2854(Preuschdorf,UpperRhineGraben,Alsace,France)asabasisofaformaldefinitionoftheUpperPechelbronnBeds(Rupelian)

6.11 MenncartB.,BeckerD.&BergerJ.-P.:DeterminationofthepaleodietandthephylogenyofextinctruminantsusingRelativeWrapAnalysisonmandibles:caseofIberomeryxminor(Mammalia,Artiodactyla)

6.12 Monnet C., Hugo B., Guex J. & Wasmer M.: Macroevolutionary trends of Acrochordiceratidae Arthaber, 1911(Ammonoidea,MiddleTriassic)

6.13 RomanoC.&BrinkmannW.:Reinvestigationofthebasalray-finnedfishBirgeriastensioeifromtheMiddleTriassicofMonteSanGiorgio(Switzerland)andBesano(Italy)

6.14 Scherler,L.TütkenT.,BeckerD.&BergerJ.-P.:TerrestrialpalaeoclimaticalandpalaeoenvironmentalreconstructionsinNorthwesternSwitzerland:carbonandoxygenisotopecompositionsofEarlyOligoceneandLatePleistoceneverte-brateremains.

6.15 UrdyS.,GoudemandN.,BucherH.&MonnetC.:Howdorecurrentpatternsofcovariationinmolluscanshellsconnecttogrowthdynamics?

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Late Aquitanian mammals from the Engehalde locality (Bern, Switzerland)

DamienBecker1,Jean-PierreBerger2,FlorentHiard2,UrsulaMenkveld-Gfeller3,BastienMennecart2,&LaurelineScherler2,1

1Section d’archéologie et paléontologie, République et Canton du Jura, Office de la culture, Hôtel des Halles, Case postale 64, 2900 Porrentruy 2, Switzerland (damien.becker@palaeojura.ch)2Département de Géosciences, Géologie et Paléontologie, Université de Fribourg, Chemin du Musée 6, 1700 Fribourg, Switzerland3Natural History Museum Bern, Bernastrasse 15, 3005 Bern, Switzerland

DuetotheconstructionoftheSwissnationalroadfromBerntoWorblaufenin1850,thesandyandmarlydepositsoftheLower FreshwaterMolasse (USM)were excavated in Engehalde. Some specimens of vertebrate fossils (turtles, ruminants,suids,andrhinocerotids)andshellsofgastropodsandbivalveswerebroughttolightbyStuder(1850).ThenStehlin(1914)reportedthepresenceofPalaeochoerus typus,butthereferredmaterialwasnotfoundinthehistoricalcollectionanymore.Thesameauthornotifiedalsotworuminants,Amphitragulus cf. elegansandAmphitragulus lemanense.However,asthesetwotaxaareconsideredsynonyms,onlyAmphitragulus elegensisvalid.Moreover,manyspecimenswronglyascribedto Amphitragulus elegansorAmphitragulus lemanense intheliterature havetobereportedtothecloserspeciesDremotherium feignouxi.There-mainsofrhinocerotidswerereviewedbyBecker(2003)andascribedtoDiaceratherium lemanense:someofthemdisplayderivedmorphologicalcharactersinterpretedasprobableintraspecificvariations.ThesehistoricdiscoveriesallowafirstdatingtotheAquitaniantime.

DuringtheconstructionoftheNeufeldtunnel(2006–2008),theancientfossillocalityofEngehaldewasmadeaccessibleforarestrictedtime.TheNaturalHistoryMuseumBernorganizedanewpalaeontologicalexcavationcampaign.Thediscoveredma-terialdidnotcontainnewrhinocerotidremains,butyieldedessentiallyspecimensofrumiants,composedbyteethandpost-cranialbonesassigned to the“Dremotherium–like”group (probablyDremotherium feignouxi).The lower left jawofamustelid,probablyfromthegenusPalaeogale,Plesictis,orPlesiogale,wasthehighlightofthenewdiscoveries(Fig.1). Thewashingandpi-ckingof sedimentsamplesallowedthesortingofcharophytes fromthegroupStephanochara praeberdotensisaswellas smallmammalremainswithProlagus sp.,Eucricetodoninfralactorensis,Peridyromyssp.andCainotheriumsp.(Menkveld-Gfeller&Becker2008).

Figure1.Lowerleftjawofamustelid-likepredator(fossillength6cm)

Thesenewdata,inparticulartheoccurenceofProlagus sp.andEucricetodoninfralactorensis,allowanimproveddatingofthislocalitytothelateAquitanian(EuropeanMammalReferenceLevelMN2;BurkartEngesser,pers.com.).Thisbiostratigraphicalinterpretation coincides with other well-dated localities reporting similar faunal composition, like the derived form ofDiaceratherium lemanense (Becker et al. 2009) and the representatives of the Amphitragulus elegans – Dremotherium feignouxigroup(Gentryetal.1999).Regardingthepalaeosynecology,thereferredmammalassociationdoesnotpermitanaccuratecharacterization of the environment of the Bern area during the late Aquitanian. However, the representatives of theAmphitragulus elegans – Dremotherium feignouxigroupcouldpointtotheexistenceofawoodedenvironment.TheirassociationwithDiaceratherium lemanense underlinesprobablyabushlandinatransitionalzonebetweenforestandgrassland.Moreover,the lithofaciesof thetrappingsediments (fluvialsandsandfloodplainmarls) indicateanenvironmentprobablyclosetobodiesofwaterorswamps.

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Becker, D. 2003: Paléoécologie et paléoclimats de laMolasse du Jura (Oligo-Miocène): apport des Rhinocerotoidea(Mammalia)etdesminérauxargileux.PhDThesis,UniversityofFribourg,GeoFocus9,327pp.

Menkveld-Gfeller,U.&Becker,D.2008:BaustelleZubringerNeufeld:eineneuealteFossilfundstelle.BulletinfürangewandteGeologie13,107-112.

Becker,D.,Bürgin,T.,Oberli,U.&Scherler,L.2009:AjuvenileskullofDiaceratheriumlemanense(Rhinocerotidae)fromtheAquitanianofEschenbach(easternSwitzerland).NeuesJahrbuchfürGeologieundPaläontologieAbhandlungen254,5–39.

Gentry,A.W.,Rössner,G.E.&Heizmann,E.P.J.1999:SuborderRuminantia.In RössneR, G.e. & HeIssIG, K. (eds.): THe MIocene Land MaMMaLs of euRope. VeRLaG dR. fRIedRIcH pfeIL, MüncHen, 225–258.

Studer,B.1850:ÜberdieSüsswassermolassebeiBern.MitteilungenderNaturforschendenGesellschaftinBern178,89–92.

6.2

Smithian ammonoids (Early Triassic): explosive evolutionary radiation following the Permian/Triassic mass extinction1

BrühwilerThomas1,BucherHugo1,2,GoudemandNicolas1,WareDavid1,HermannElke1

1Paläontologisches Institut und Museum der Universität Zürich, Karl Schmid-Strasse 4, 8006 Zürich (bruehwiler@pim.uzh.ch) 2Department of Earth Sciences, ETH, Universitätsstrasse 16, 8092 Zürich

In the aftermath of the end-Permianmass extinction, ammonoidswere among the fastest clades to recover: the recentanalysisofaglobaldiversitydatasetofammonoidgenerafromtheLateCarboniferoustotheLateTriassicshowsthatTriassicammonoidsactuallyreachedlevelsofdiversityhigherthaninthePermianlessthan2millionyearsafterthePTB(Brayardetal.,2009).TheevolutionofEarlyTriassicammonoidswasnotasmooth,norgradualprocess. It ischaracterizedbythefollowingmainfeatures:(i)averylowdiversityintheGriesbachian(earlyInduan),(ii)amoderatediversityincreaseintheDienerian(lateInduan),(iii)anexplosiveradiationintheearlySmithian(earlyOlenekian),(iv)alateSmithianextinctioneventfollowedbyasecondexplosiveradiationintheearlySpathian(lateOlenekian)(Brayardetal.,2006,2009).

InordertobetterunderstandtheSmithianammonoidradiationweconductedextensivefieldstudiesintwoclassicalregionsfortheEarlyTriassic,namelytheSaltRange(Pakistan)andSpiti (IndianHimalayas).Smithianammonoidsfromthesere-gionshavebeenknownformorethanacentury,andtheseplacesarethetypelocalitiesofmanytaxa(e.g.Waagen,1895;Krafft&Diener,1909).Additionally,westudiedasectionatTulong(SouthTibet)aswellasextremelyammonoid-richexoticblocksofHallstattLimestoneintheOmanMountains.

Ourabundant,bed-rock-controlledandwell-preservedmaterialenablesustorevisemanyclassicalammonoidtaxathatwerepreviouslyknownonlyinadequately.Moreover,alargenumberofnewtaxawasfound,whichenablesustodefineonenewfamily,18newgeneraandabout29newspecies.Atotalofeightsuccessiveammonoidassociationscanbecorrelatedbetweenoursections(Brühwileretal.,2007).Thishigh-resolutionbiochronologicalschemefortheSmithianoftheNorthernIndianMargincanbecorrelatedwithammonoidsuccessionsfromotherregionssuchasSouthChina(Brayard&Bucher,2008).

DuetotheveryhighevolutionaryratesofEarlyTriassicammonoids(Brayardetal.,2009)thereconstructionofphylogeneticrelationshipsamongSmithianammonoidsisdifficult.However,ourwell-constrainedtaxonomicandbiochronologicdataprovidenewinsightsontheevolutionofseverallineages.Furthermore,theongoingcomprehensivestudyofDienerianam-monoidfaunasfromtheSaltRangeandfromSpiti(Wareetal.)willhelpustodecifertheoriginofsomeSmithianammo-noids.

1ThisresearchissupportedbytheSwissNSFproject200020-113554.

REFERENCESBrayard,A.&Bucher,H. 2008: Smithian (Early Triassic) ammonoid faunas fromnorthwesternGuangxi (SouthChina):

taxonomyandbiochronology.FossilsandStrata,55,1-179.Brayard,A.,Bucher,H.,Escarguel,G., Fluteau,F.,Bourquin,S.&Galfetti,T.2006:TheEarlyTriassicammonoidrecovery:

Paleoclimaticsignificanceofdiversitygradients.Palaeogeography,Palaeoclimatology,Palaeoecology,239,374–395.Brayard,A.,Escarguel,G.,Bucher,H.,Monnet,C.,Brühwiler,T.,Goudemand,N.,Galfetti,T.&Guex,J.,2009:GoodGenesand

GoodLuck:AmmonoidDiversityandtheEnd-PermianMassExtinction.Science,325,1118-1121.Brühwiler,T.,Bucher,H.,Goudemand,N.&Brayard,A.2007:Smithian(EarlyTriassic)ammonoidfaunasoftheTethys:new

preliminaryresultsfromTibet,India,PakistanandOman.TheglobalTriassic:NewMexicoMuseumofNaturalHistoryandScienceBulletin,41.

Krafft,A.v.&Diener,C.,1909:LowerTriassiccephalopodafromSpiti,MallaJohar,andByans.PalaeontologiaIndica,ser.15,6,1-186.

Waagen,W.,1895:Salt-Rangefossils.Vol2:FossilsfromtheCeratiteFormation.PalaeontologiaIndica13,1-323.

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Darwinian dinosaurs : missing links or evolutionary failures ?

EricBuffetaut

CNRS, UMR 8538, Laboratoire de Géologie de l’Ecole Normale Supérieure, 24 rue Lhomond, 75231 Paris Cedex 05, France (eric.buffetaut@sfr.fr)

CharlesDarwindidnotoftenmentiondinosaursinhisworks.InthethirdeditionofOn the origin of species (1861,p.346),healludedtotheminachapteraboutextinction:“Solittleisthissubjectunderstood,thatIhaveheardsurpriserepeatedlyexpressedatsuchgreatmonstersastheMastodonandthemoreancientDinosaurianshavingbecomeextinct;asifmerebodilystrengthgavevictoryinthebattleoflife.Meresize,onthecontrary,wouldinsomecasesdeterminequickerextermi-nationfromthegreateramountofrequisitefood”.Tenyearslater,inThe descent of man, and selection in relation to sex(1871,p.204),heemphasizedtheirevolutionarysignificance:“Prof.Huxleyhasmadetheremarkablediscovery,confirmedbyMr.Copeandothers,thattheoldDinosauriansareintermediateinmanyimportantrespectsbetweencertainreptilesandcer-tainbirds—thelatterconsistingoftheostrich-tribe(itselfevidentlyawidely-diffusedremnantofalargergroup)andoftheArcheopteryx,thatstrangeSecondarybirdhavingalongtaillikethatofthelizard”.

ThusDarwinillustratedtwoviewsofdinosaursthatweretobecomebothprevalentandcompetinguntiltoday:iconsofex-tinction,ormissinglinks.The“missinglink”interpretationpredominatedduringthelastpartofthe19thcenturyandthebeginningofthe20th,whendinosaurswerewidelyconsideredasancestraltobirds,onthebasisofosteologicalresemblanceandthediscoveryofbothArchaeopteryxandthe“toothedbirds”,HesperornisandIchthyornis,fromtheLateCretaceousoftheUnitedStates.Accordingtothisview,dinosaurs,asbirdancestors,hadplayedanimportantpartintheevolutionofoneofthemost successful groupsof living vertebrates. This interpretation fell outof favourduring themid-twentieth century,largelybecauseoftheinfluentialbookbyGerhardHeilmann,The origin of birds (1926), inwhichthepurportedabsenceofclaviclesindinosaurswasusedtodemonstratethattheycouldnotpossiblyhavebeenancestraltobirds(whichpossessclavi-cles)–since“Dollo’slaw”stipulatesthatonceanorganhasbeenlostinthecourseofevolution,itcannotreappearagain.

Asdinosaurscouldnolongerbeseenasancestraltoanything,theyhadtobeconsideredassomekindofevolutionarydeadend,andthisinterpretationprevaileduntilthe1970s.Theimageofthedinosaursastoolarge,tooslowandtoostupidtohavebeenabletosurvivebecameprevalentforalargepartofthe20thcentury.Thiscouldbeseenintermsofnaturalselec-tion,withlargefoodrequirementsasapossibledisadvantage,asalreadymentionedbyDarwinin1861,orintermsofnon-Darwinian,orthogeneticevolutionresultinginnon-adaptivetransformationsdetrimentaltotheorganismsinvolved.Theideathatdinosaursweresomehow“doomed”toextinctionbyratherobscureevolutionarymechanismsbecamepopularforalongtime.

Thingschangedagaininthe1970swhendinosaurbiologywasthoroughlyreinterpretedandtheimageofsluggish,cold-blooded giantswas challenged and a new view of dinosaurs asmore active, possiblywarm-blooded, animals graduallyemerged.Thiswenttogetherwithareappraisalofdinosaur-birdrelationships,basedonnewdiscoveriesofsmallcarnivo-rousdinosaursanddescriptionsofnewspecimensofArchaeopteryx,whichresultedinarebirthofthehypothesisofthedi-nosaurian ancestry of birds. This was strengthened by the discovery of clavicles in many dinosaurs (thus eliminatingHeilmann’sobjection)andbythatofthefamous“feathereddinosaurs”fromtheEarlyCretaceousofChina,whichprovideextremelystrongevidenceinfavourofaclosephylogeneticrelationshipbetweensmalltheropoddinosaursandbirds.

Inthe1980s, thequestionofdinosaurextinctionalsounderwentarevival,withinthe larger frameworkofcatastrophiceventsattheCretaceous-Tertiaryboundary.Thediscoveryofthemajorasteroidimpactthathappened65millionyearsagoledtoathoroughreconsiderationofthepossiblecausesofterminalCretaceousextinctions, includingthatofnon-aviandinosaurs.Seenaspartofmajorextinctioneventaffectingmanygroupsoforganismsinvariousenvironments,inalllike-lihoodcausedbytheimpactofanextra-terrestrialobject,thedisappearanceofthedinosaurscouldnolongerbeseenastheresultofsomemysteriousinabilitytoadapttogradualenvironmentalchange.AlthoughthedetailsofdinosaurextinctionattheendoftheCretaceousremaintobeworkedout,thereasonfortheirdisappearanceisnowmuchclearerthanitwasbeforethediscoveryoftheend-Cretaceousimpact–andDarwin’soriginalremarkabouttheimportanceoffoodresources(orthelackthereof)takesonanewsignificanceinviewofcurrenthypothesesaboutthecollapseoffoodwebsfollowingtheasteroidimpact.

Althoughtheevolutionarysignificanceofdinosaurs,bothintermsofextinctionandofintermediateforms,wasapparenttoDarwin,andtoquiteafewofhisfollowers,includingHuxley,inthe19thcentury,itwasunderratedduringmuchofthe20thcentury.Itisonlysincethe1990sthatpalaeontologistshaverecognisedagainthatdinosaurswerenotsimplyanextinctgroupofreptiles,butwereinfactthesourceofoneofthemajorgroupsoflivingvertebrates,viz.thebirds,andthatthedemiseofnon-aviandinosaurswastheresultofanexceptionalglobalevent,ratherthantheconsequenceofsomekindofnon-adaptiveevolution.Theexampleofdinosaursillustrateswellhowtheoutdatedconceptof“evolutionaryfailures”hasbeensupersededbyamoretrulyDarwinianinterpretationofthefossilrecord.

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Darwin,C.1861:On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life.3rdedition.JohnMurray,London.

Darwin,C.1871:The descent of man, and selection in relation to sex.JohnMurray,London.Heilmann,G.1926:The origin of birds.Witherby,London.

6.4

Diatom assemblage turnover in the NW-Pacific at the 2.73 Ma climate transition

GiraultFranceE.&ThiersteinHansR.

Geological Institute, ETH, Sonneggstrasse 5, CH-8092, Zurich (france.girault@erdw.ethz.ch)

TheNorthPacificcontainsacriticaldiatomsedimentaryrecordoftheCenozoicglobalcoolinghistory.ThemoststrikingpartofthatrecordcoverstheultimateclosureofthePanamaSeaway2.73MaagowhichwassynchronouswiththeonsetofNorthernHemisphereglaciations(NHG).Thesephysicalchangeswereconcomitantwithanabruptchangeinthebiologicalpumpefficiencyrelatedtotheonsetofoceansurfacewaterstratification.TheODPsite882record(Leg145)-withitswellconstrainedNeogenepaleoceanographichistoryaroundthe2.73Matransi-tion-providesanexcellentbasistotestpatternsandpotentialcontrolsofdiatomsizevariabilityandspeciesdominance.Frustulesizesofcentricdiatomshavebeenquantifiedtobetterunderstandtheenvironmentalresponseoftheseorganismstoadrasticandpermanentpaleoceanographicandclimaticchange.Sizeandmorphologicalcharacteristicsofthecentricdiatomfrustules (diameter>20µm)werecollectedforastatisticallyrepresentativenumberofspecimens(i.e.250-700)persampleusingrecentlydevelopedautomatedlightmicroscopyandim-ageanalysistechniques.

6.5

Neogene global cooling: diatom size variability in a changing ocean

GiraultFranceE.1,WellerAndrewF.1,2&ThiersteinHansR.

1 Geological Institute, ETH, Sonneggstrasse 5, CH-8092, Zurich (france.girault@erdw.ethz.ch)2 Present address: Geosoft Australia Pty Ltd, 14/100 Railway Road, Subiaco WA 6008, Australia

Overthepast40Ma,thedevelopmentandstepwiseexpansionoftheAntarcticice-sheet,togetherwithtectonicmovements(e.g.closureofthePanamaisthmus)havedeeplymodifiedthepatternsofglobalcirculationandchemicalsignatureofthevariouswatermasses(e.g.redistributionofdissolvedsilica).Thesechangeshavealsoinducedthedevelopmentofoceanicboundaries(e.g.Polarfront),directlyaffectingtheevolutionofplankticmicro-organisms.Usingthewidespreadrecordof siliceousmicrofossils (SouthernOcean,EquatorialPacificandNorthPacific),wehaveas-sessedtheimpactsoftheseoceanographicreorganizationsondiatoms,focusingonsizeandtaxonomicchangesandturno-versamongcentricdiatomsoverthepast15Ma.TheabilityofdiatomstoadaptandsurviveinachangingoceanhasprobablybeenakeyfortheirsurvivalespeciallyovertheNeogene,whenclimaticandoceanographicchangeshavebeenthestrongest.Similarly,sizevariabilityamongthisgrouptightlyreflectstheirresponsetoenvironmentalperturbationsaswellastheirtaxonomicturnoversthathavebeendrivingdiatomevolutionarypatternstowardhighlydiverseandendemiccommunitiesprevailingintoday’soceans.

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Paleobiology of Early Triassic conodonts: implications of newly discove-red fused clusters imaged by X-ray synchrotron microtomography

GoudemandNicolas1,OrchardMichael2,TafforeauPaul3,UrdySéverine1,BrühwilerThomas1,BucherHugo1,BrayardArnaud§,GalfettiThomas1,MonnetClaude1,LebrunRenaud§§&ZollikoferChristoph§§

1Paläontologisches Institut und Museum, Universität Zurich, Karl Schmid-Str. 4, 8006 Zürich (goudemand@pim.uzh.ch). 2Geological Survey of Canada, 101-605 Robson St., Vancouver,BC, V6B 5J3 Canada.3European Synchrotron Radiation Facility, 6 rue Jules Horowitz, BP 220, 38043 Grenoble cedex, France. §UMR-CNRS 5561 Biogéosciences, Université de Bourgogne, 6 Bd Gabriel, 21000 Dijon, France.§§Anthropologisches Institut und Museum, Universität Zürich, Winterthurerstrasse 190, 8057 Zürich

SeveralfusedclustersofconodontelementsoftheEarlyTriassicgenusNovispathodus werediscoveredinlimestonebedsattheSmithian-Spathianboundary(LuolouFormation.,Galfettiet al.,2008)fromseverallocalitieswithintheGuangxiprovinceof South China. Conodont clusters are groups ofmorphologically different elements belonging to the same individual,whichweresomehowcementedtogetherpost-mortem.SuchspecimensofexceptionalpreservationareextremelyrareintheTriassicandthesearethefirstreportedfortheEarlyTriassic.Ourfusedclusterspartiallypreservetherelativethree-dimensionalpositionandorientationofsomeramiform,graspingelements.Theyarethereforeextremelyimportantforourunderstandingofthefeedingapparatusesofconodonts.Becauseoftheintricategeometryofthesuperposedelements,oftheirfragilityandoftheirextremerarity,itisusuallytrickytostudysuchspecimens.Weovercometheseproblemsbyperformingapropagationphasecontrastsynchrotronmicrotom-ography(Tafforeauet al.,2006).Apinkbeamsetupat17.6keV,whichwasveryrecentlydevelopedattheEuropeanSynchrotronRadiationFacilityonbeamlineID19,hasbeensuccessfullytestedonourconodonts.Thisnewtechniqueenablesasubmicronresolution(0.23µm)withaspeedandanoverallqualityneverreachedbefore.Somefusedclustersaswellasco-occurringisolatedelementsfromthesamesampleandpertainingtothesamemulti-elementspecieswerescannedusingthistech-nique.BesidestaxonomicrevisionoftheGondolelloideasuperfamily(themostsignificantgroupofconodontsduringPermianandTriassictimes),thisdiscoveryledustoproposeanewfunctionalmodel.Inourview,thebestsolutionimpliesthepresenceofapresumablycartilaginous‘copula’,uponwhichtheconodontele-mentsaremovingindependently,moreorlessasdodentalplatesinextantlampreys,butnotstrictlyasproposedbyPurnellandDonoghue (1997).Wesuggest thatduringretractiontowards thecaudally locatedplatform (cuttingorgrinding)ele-ments,theS0elementfirsthasaclosing,rotatingmovement,mostprobablysynchronizedwiththeclosureoftheMele-ments,withwhichitwouldhaveperformedapinching,seizingfunction.Thismovementisthenfollowedbyasub-straight,dorso-caudallydirectedtranslation,bywhichitwouldhavetornofftheprey’s‘flesh’andbroughtittowardstheplatformelements.ThelattermovementisaccompaniedbytheclosureoftheotherSelements,channellingthefoodintheappropri-atedirection.Consideringthatthepresenceofsuch‘copula’associatedwithtongueprotractorandretractormuscleshasbeenassertedonlyforextantcyclostomes(hagfishesandlampreys;Yalden,1985;Donoghueet al.,2000),ournewmodelmayprovideim-portantinsightsfordecipheringtheaffinityofconodontsandforourgeneralunderstandingoftheoriginofvertebrates.

AcknowledgementsThisresearchissupportedbytheSwissNSFproject200020-113554.WeacknowledgetheEuropeanSynchrotronRadiationforprovisionofsynchrotronradiationfacilitiesandforgrantingaccesstobeamlineID19.

Figure1.Animated3dreconstructionofthefeedingapparatusofNovispathodus.

REFERENCESGalfetti,T.,Bucher,H.,Martini,R.,Hochuli,P.A.,Weissert,H.,Crasquin-Soleau,S.,Brayard,A.,Goudemand,N.,Brühwiler,

T.&Guodun,Kuang2008. Evolutionof Early Triassic outerplatformpaleoenvironments in theNanpangjiangBasin

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gy (SouthChina)andtheirsignificanceforthebioticrecovery.Sed.Geol.204:36-60.

Tafforeau, P., et al. 2006. Applications of X-ray synchrotronmicrotomography for non-destructive 3d studies ofpaleontologicalspecimens.Appl.Phys.A83:195-202.

Purnell,M.A.&Donoghue,P.C.J.1997.ArchitectureandfunctionalmorphologyoftheskeletalapparatusofOzarkodinidconodonts.Phil.Trans.R.Soc.Lond.B352:1545-64.

Yalden,D.W.1985.Feedingmechanismsasevidenceofcyclostomemonophyly.Zool.J.Linn.Soc.84:291-300.Donoghue,P.C.J.,Forey,P.L.&Aldridge,R.J.2000.Conodontaffinityandchordatephylogeny.Biol.Rev.75:191-251.

6.7

The Devonian Nekton Revolution

Christian Klug1, Björn Kröger2, Wolfgang Kiessling2, Gary L. Mullins3, Thomas Servais4, Jiří Frýda5, Dieter Korn2 & Sue Turner6

1Paläontologisches Institut und Museum, Universität Zürich, Karl Schmid-Strasse 4, CH-8006 Zürich, Switzerland, (chklug@pim.uzh.ch) 2Museum für Naturkunde, Humboldt-Universität zu Berlin, Invalidenstraße 43, D-10115 Berlin, Germany3Department of Geology, The University of Leicester, University Road, Leicester, LE1 7RH, United Kingdom4Laboratoire de Paléontologie et Paléogéographie du Paléozoïque, UMR 8014 du CNRS, Université des Sciences et Technologies de Lille, SN5 Cité Scientifique, F-59655 Villeneuve d’Ascq, France5Faculty of Environmental Science, Czech University of Life Sciences, Kamýcká 129, 165 21 Praha 6 Suchdol, Czech Republic6Queensland Museum, 122 Gerler Rd., Hendra, Queensland 4011, Australia

ImpressivediscoveriesofNeoproterozoicandEarlyPalaeozoicFossillagerstaettendrewtheattentiononevolutionaryandecologicalprocessesofthesetimespans.Italmostseemedthat,exceptforsomeofthe“BigFive”,nothingessentialhappenedaftertheOrdovician.Suchascenarioiscertainlynottrue.

Contrariwise,somemajorecologicalfluctuationshavebeenrecordedfromtheDevonian,severalofwhichhavelesspromi-nentSilurianprecursors.Famousexamplesaretheradiationoflandplantsandjawedfish(bothknownalreadyfromthepre-Devonian).DuringtheDevonian,severalanimalgroupsconqueredtheland(variousarthropodsandpossiblytetrapods).Marineinvertebratesshowsignificantecologicalandmorphologicalchanges:Importantcephalopodgroupssuchasbactri-toidsaswellasammonoidsevolvedandreefgrowthincreaseduntiltheLateDevoniancrises.Boththeglobalriseandfallofdacryoconaridsoccurred,graptolitesbecameextinct,andvariousmollusccladesmodifiedearlyontogeneticstrategiesdur-ingtheDevonian,documentingaplanktonicturnover.Inaddition,thereisamacroecologicalchangeinmarinefaunasfromademersal(swimmingclosetothesea-floor)andplanktonichabittowardsamoreactivenektonichabit.

VariousinterpretationsareathandtoexplainthisDevonianNektonRevolution: (1)Demersalandnektonicmodesoflifewereprobablyinitiallydrivenbycompetitioninthediversity-saturatedbenthichabitatsaswellas(2)theavailabilityofrichplanktonicfoodresources(asreflectedinevolutionaryalterationsinearlyontogeneticstagesofmanymollusks).Escalatoryfeedbacksprobablypromotedtherapidevolutionofnekton(jawedfishandsomederivedcephalopodgroupsinparticular)intheDevonian,assuggestedbythesequenceandtempoofwater-columnoccupation.Potentially,boththeseradiationsandtheGivetiantoFamennianmass-extinctionswerelinkedtoapronouncedincreaseinnutrientinputtoseasurfacewatersduringeutrophicationepisodes.

6.8

Red trilobites with green eyes from the Devonian of Morocco

ChristianKlug1,HartmutSchulz2andKennethDeBaets1

1Paläontologisches Institut und Museum der Universität Zürich, Karl Schmid-Str. 4, CH-8006 Zürich (chklug@pim.uzh.ch)2Institut für Geowissenschaften, Eberhard-Karls-Universität Tübingen, Sigwartstr. 10, D-72076 Tübingen, Germany

Latest Emsian (Early Devonian) sediments at the famous mud-mound- and trilobite-locality Hamar Laghdad (Tafilalt,Morocco)yieldedsomewellpreserved,largelyred-colouredremainsofphacopidtrilobites.Closerexaminationrevealedthatonlythelensesoftheeyesofthesephacopidsareusuallygreenishincolour.EDX-analysesshowedthatthelensesretainedtheiroriginalcalciticcompositionwhilemostoftheexoskeletonwassilicified.Thesilicifiedpartscontainelevatedconcen-trationsofironwhichcausestheredcolour.

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yPresumably,theprimaryporosityofmostofthephacopidexoskeletonexceptthechitinouslegsandthelenseswas,becauseoftheporecanals,higherthanthatofthelenses,facilitatingthereplacementofcalcitebyotherminerals.Furthermore,thepresenceoforganiccomponentsinthelensesincombinationwithahomogeneousdistributionofthecalcitecrystalsmighthaveslightlyincreasedtheresistanceofthelensestowardsmineralreplacement.Thehomogeneityofthecalcitecrystalsofthelenseswasneededfortheiroptimalopticalfunctionality.Thesefactorsprobablyaccountforthefactthattheeyesreta-ined the calcitewhich is oftengreenish inbrachiopod shells suchas the thick-shelledMiddleDevonianDevonogypa andIvdeliniafromtheMaïderBasinwhiletherestofthetrilobiteexoskeletonisred.Thisdifferentialreplacementalsoexplainswhythelensesareslightlycorrodedwhiletherestoftheexoskeletonissuperficiallywellpreserved.Sofar,thisdifferentialreplacementofcalciteisonlyknownfromtheeyesofphacopids.Othertrilobitetaxafromthesamestrataandlocalityhaveholochroaleyesandthusmuchsmallerlenseswhichwereprobablymorerapidlyreplacedbysilica.Thegreenishcolourofthe lensesmightoriginatefromimpuritiesof ironandmagnesium;theconcentrationsofthecorrespondingionsmighthavebeentoolowtobedetectedwiththeEDXwithcertainty.

HamarLaghdadalsoyieldedphacopidexoskeletonswith lesscompletelysilicifiedexoskeletonswhichenabledadetailedreconstructionofthesilicificationprocess.Initially,onlytheoutersurfaceoftheexoskeletonandthevicinityofporecanalsweresilicified.Inasecondstep,thebendinthegrowthlinesoftheinterlensarscleraweresilicifiedtogetherwiththere-mainingexoskeletonexceptforthelenses,thenthecompleteinterlensarscleraandintheendalsothelenses.

6.9

First record of a belemnite preserved with beaks, arms and ink sac from the Nusplingen Lithographic Limestone (Kimmeridgian, SW Germany)

ChristianKlug1,GünterSchweigert2,DirkFuchs3andGerdDietl2

1Paläontologisches Institut und Museum, Karl Schmid-Str. 4, CH-8006 Zürich (chklug@pim.uzh.pim)2Staatliches Museum für Naturkunde, Rosenstein 1, D-70191 Stuttgart, Germany3Institut für Geowissenschaften, Freie Universität Berlin, Malteserstr. 74-100, D-12249 Berlin, Germany

A recent discovery of anunusually preserved belemnite fromNusplingen comprises the extraordinarily rare remains ofbeaksandnearly in situ arm-hooksaswellas the ink sacand the incompletephragmocone.So far,Hibolithes semisulcatus(Münster, 1830) is the only larger belemnite known from the Nusplingen Lithographic Limestone (Upper Jurassic, LateKimmeridgian,BeckeriZone,UlmenseSubzone;SWGermany)whichhasthesamephragmoconeshapeandsize,thusweassignthenewspecimentothistaxon.Therostrumwasprobablylostduetoalethalpredationattemptinwhichthepreywaskilledbutnotentirelyeaten.Forthefirsttime,aspecimenrevealsdetailsofthebelemnitebeakmorphology,whichwecomparetothebeaksofotherJurassiccephalopods.Thisspecimenpresentlyrepresentstheonlyknownrostrum-bearingbelemniteofpost-Toarcianagewhichhasbeenpreservedwithnon-mineralisedbodyparts.AsHibolithes semisulcatus isknowntopossessonepairofmega-onychites,theabsenceofthoseinthepresentspecimenprovidesevidenceofsexualdimorphisminHibolithes semisulcatus. Thisphenomenonwaspreviouslypresumedforallbelemnites,butitisknownonlyfromPassaloteuthiswithcertaintysince therostrumofthelatterisunambiguouslyassociatedwithanarmcrownthatoccasionallyincludesonepairofmega-onychites.TheimperfectpreservationofthebelemnitebeakshampersadetailedcomparisonwithotherRecentandfossilcoleoidbeaks.Somemorphologicalcharacters(lowwidthoftheouterlamella,doublelaterallobesofthedarkpartsofrostrumandhood,possiblyshortinternallamella)ofthelowerbeakofHibolithes morecloselyresembleRecentde-capodsthanRecentoctopods.TheupperbeakofHibolithes differsinthelong,narrowandcurvedrostrumfromthosecoleoidbeakspreviouslyknownfromNusplingen.Thedarkpartofthelowerbeakalsoshowsauniqueoutlinewithashortandpointedrostrum,anelongateposteroventralextensionandtwosmall roundedsinuseswhichpointedtowards thewings(sometimes similarlydeveloped inRecentSepioteuthis). It appears likely that this beak form is quite characteristic and itmightreflectaspecialdietofthebelemnites.Takingtheirprobablyhighswimmingvelocity(fins,stream-linedbody,andhorizontal orientationof the longest body axis)with the armhooks and the sharpbeaks into account, it appearsquitelikely that belemniteswere fast-swimming, effective,medium-sized predators.With the newdiscovery,NusplingennowrepresentstheonlylocalitywhichhasyieldedcompletebeakapparatusesfromallmajorJurassiccephalopodgroups.

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The borehole 01983X2854 (Preuschdorf, Upper Rhine Graben, Alsace, France) as a basis of a formal definition of the Upper Pechelbronn Beds (Rupelian)

LavoyerThibault,YerlyBertrand&BergerJean-Pierre

Département de Géosciences, Géologie et Paléontologie, Université de Fribourg, chemin du Musée 6, 1700 Fribourg, Switzerland

FromthemiddleEocenetoLateOligocene,anintenselacustrine,brackishandmarinesedimentation,documentedbysaltdepos-itsandoilaccumulation,tookplaceintheUpperRhineGraben(URG),especiallyinthePechelbronnBeds(Lower-,Middle-andUpper).

Althoughtheselayerswerestudied,inthepast,fortheoilindustry(Schnaebele1948)andarealithostratigraphicunitusedinmapsandpapersconcerningthePaleogeneoftheURG,theyhaveneverbeenformallydesignatedbecausetheyalmostnevercropoutat thesurfaceanddriftinganddrillingmaterialswereoftendiscarded.Nevertheless, the InternationalStratigraphicGuide(seeMurphyandSalvador1999),demandsatypesectionforeachformallynamedFormation.

SeveralpalaeogeographicalreconstitutionsandstratigraphicchartsfortheURGhavebeenpublished(Bergeretal.2005a&b).However,theRupeliandepositswerenotwelldefined.

ThisworkpresentsthefirststepforadefinitionofatypesectionofatypesectionoftheUpperPechelbronnBeds,withthepresentationofseverallithofaciesandpaleontologicaldata.

Thestudiedborehole,01983X2854(Preuschdorf,Alsace,France)isacompletecoreddrilling,about220mindepth.Itwasoriginallymadetoevaluateadecontaminationissue,buthasalsoyieldedmicropaleontologicalandsedimentologicaldata.ItcorrespondstotheUpperPechelbronnBedswithasmallpartoftheMiddlePechelbronnBedsatthebase.

Thehighabundanceofostracodsandgastropodsingreymarls,correspondingtothe10lowermeters,indicatethetopoftheMiddlePechelbronnBedswiththeHydrobiaZone.Theselayersarecoveredbyasuccessionofmarlsandsandstone,suggest-ingadifferentenvironment.ThelowerpartoftheboreholeisconsistentwiththelithostratigraphiczonationdefinedbySchnaebele(1948)forhis“normalfacies”whereastheupperpartcorrespondstohis“freshwaterfacies”.

The lower part of the borehole has yielded new paleontological data. Diatoms (Triceratium sp), charophytes (Chara spp.,Rhabdocharasp.), foraminifers (Ammodiscussp.,Quinqueloculinasp.,Flintinasp.,Lenticulinaspp.,Dentalinasp.,Subreophax elon-gates, Vaginulopsis spp.), bivalves, gastropods, bryozoans, ostracods (Grinioneis tribeli, Hazelina indigena, Hemicyprideis spp.,Ilyocyprissp.),insects,echinoderms,fishesandmammalsteethareusedasmainindicatorsofbiostratigraphyandpalaeoecol-ogy.Thefossilrecordemphasizesacomplexalternationoffreshwater,brackishandmarinefaunaalongthewholestudiedsection.

This study is financedby theSNFProject200020-118025 “PaleontologyandStratigraphyof theRhinegrabenduring thePaleogene”,andincludespartsoftheMasters-thesisofB.Yerly“ThetransitionbetweentheMiddleandUpperPechelbronnBedsinthedrilling1983X2854,Preuschdorf(Rupelian,UpperRhineGraben,Alsace,France)”(inprep.2009)andthePhD-thesisofT.Lavoyer“PaleontologyandStratigraphyoftheMiddleUpperRhineGrabenduringthePaleogene:akey-studyfortherelationshipsbetweenRiftsystem,AlpineOrogenyandPaleoclimate”(inprogress).

We thank S. Spezzaferri (Uni. Fr., foraminifers), C. Pirkenseer (Uni. Leuven, ostracods) for fossils determination, P. Elsass(BRGM)andM.Kimmel(Geoderis)forprovidingaccesstothecoredrilling.

REFERENCESBerger,J.-P.etal.,2005a.PaleogeographyoftheUpperRhineGraben(URG)andtheSwissMolasseBasin(SMB)fromEoceneto

Pliocene.InternationalJournalofEarthSciences,94(4):697-710.BergerJ.-P.etal.,2005b.Eocene-PliocenetimescaleandstratigraphyoftheUpperRhineGraben(URG)andtheSwissMolasse

Basin(SMB).InternationalJournalofEarthSciences,94(4):711-731.MurphyM.A.&SalvadorA.1999.InternationalStratigraphicGuideAnabridgedversion.Episodes,Vol.22,no.4SchnaebeleR., 1948.Monographiegéologiquedu champpétrolifèredePechelbronn. –MémoiresduServicede laCarte

géologiqued’AlsaceetdeLorraine,7:254SStrasbourg

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Determination of the paleodiet and the phylogeny of extinct ruminants using Relative Wrap Analysis on mandibles: case of Iberomeryx minor (Mammalia, Artiodactyla)

BastienMennecart1,DamienBecker2&Jean-PierreBerger1

1Department of Geosciences – Earth Sciences, ch. du Musée 6, Pérolles, 1700 Fribourg, Switzerland (bastien.mennecart@unifr.ch)2Section d’archéologie et paléontologie, République et Canton du Jura, Office de la culture, Hôtel des Halles, Case postale 64, 2900 Porrentruy 2, Switzerland

TheprimitiveruminantIberomeryxisessentiallyknownbyfewdentalremainsandisstillpoorlydocumented.Itsphylogenyandpalaeobiologystaysratherenigmatic.Onlytwospecieshavebeendescribed:thetypespeciesI. parvusfromtheBenaralocalityinGeorgia(Gabounia1966),andtheWestEuropeanspeciesI. minorfromItardies,Mounayne,RaynalandRoqueprune2inQuercy (Sudre1987),MontalbaninSpain(Golpe-Posse1974),andLovagny,Soulceand BeuchilleintheSwissMolasseBasin(Beckeretal.2004).I. savageifromIndiahadrecentlybeenplacedinthenewgenusNalameryx (Métaisetal.2009).AlltheselocalitiesaredatedtotheRupelianandcorrespondmainlytoMP23(Europeanmammalbiozone).Basedontheshorttooth-crownheightandthebunoselenodontpatternofthemolars,Sudre(1984)andBeckeretal.(2004)proposedafolivore/frugivoredietforIberomeryx.

Basedonrelativewarpanalysis(24landmarks)of84extantandfossilruminantmandiblesfrom24generaand32species,thisstudyproposesapreliminarydiscussiononthephylogenyandthedietofthegenusIberomeryx.TheresultspermittodifferentiatePecoraandTragulinaonthefirstaxisthankstothelengthofthediastema,thelengthofthepremolarsandthemandibleankle.AssuggestedbySudre(1984),IberomeryxisclosetotheextantTragulinabytheshapeofitsmandible.But,thislatterisclearlydifferentofthoseoftheTragulidae,theonlyextantfamilyinTragulina.Thisdifferenceisessentiallyduetoastockiermandible (condylarprocess,mandibleramusandcorpus mandibulae),andadeepermandibularincisure.Additionally,weobservenodiastemaandwellbunodontteeth.IberomeryxmaybeconsideredasaprimitiveTragulidae,theonlyknownfromtheOligocene,basedonthegeneralshapeofitsmandibleanditsjawteeth.Moreover,itsdietcouldnotbestrictlyfrugivore,butitcouldpossiblyalsoexceptionallyeatsomemeatmattersuchassmallHypertragulidae.

ThisstudyissupportedbytheSectiond'archéologieetpaléontologie(Porrentruy),theUniversityofFribourg,andtheSwissNationalFoundationproject(115995)onthelargemammalevolutionintheSwissMolasseBasinduringtheOligoceneandEarlyMiocene.

REFERENCESBecker,D.,Lapaire,F.,Picot,L.,Engesser,B.&Berger,J.-P.2004:Biostratigraphieetpaléoécologiedugisementàvertébrésde

LaBeuchille(Oligocène,Jura,Suisse).RevuedePaléobiologie,Vol.spéc.9,179-191.Gabounia,L.1966:SurlesMammifèresoligocènesduCaucase.BulletindelaSociétéGéologiquedeFrance7,857-869.Golpe-Posse,J.1974:FaunasdeYacimientosconSuiformesenelTerciarioespanol.PublicacionesdesInstitutoProvincialde

PaleontologiadeSabadell,PaleontologiayEvolucion8,1-87.Métais,G.,Welcomme, J.-L-&Ducrocq, S. 2009:New lophiomericyd ruminants from theOligocene of theBugtiHills

(Balochistan,Pakistan).JournalofVertebratePaleontology29(1),231-241.Sudre, J. 1984:CryptomeryxSchlosser, 1886, tragulidéde l'Oligocèned'Europe; relationsdugenre et considérations sur

l'originederuminants.Palaeovertebrata14,1-31.

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Macroevolutionary trends of Acrochordiceratidae Arthaber, 1911 (Ammonoidea, Middle Triassic)

MonnetClaude1,BucherHugo1,GuexJean2&WasmerMartin1

1Paläontologisches Institut und Museum, Universität Zürich, Karl Schmid Strasse 4, CH-8006 Zürich (claude.monnet@pim.uzh.ch, hugo.fr.bucher@pim.uzh.ch, martin.wasmer@gmail.com)2Institut de Géologie et Paléontologie, Université de Lausanne, BFSH-2, CH-1015 Lausanne (jean.guex@unil.ch)

Directedevolutionoflifethroughmillionsofyears,suchasincreasingcomplexityandincreasingadultbodysize,isoneofthemostintriguingpatternsdisplayedbyfossillineages.ThegeneraltendencyforbodysizetoincreaseduringtheevolutionofagroupofanimalsisknownasCope’srule.Processesandcausesofsuchmacroevolutionarytrendsremainhowevertobeclearlyunderstood (Jablonski2000).Amongfossils,ammonoidshells (marinecephalopods)arewellknowntoexperiencerepetitivemacroevolutionarytrendsoftheiradultsize,geometryandornamentation(Schindewolf1940;Haas1942;Bayer&McGhee1984;Dommergues1990;Guex1992).

ThisstudyanalyzestheevolutionarytrendsofthefamilyAcrochordiceratidaeArthaber,1911,whichspannedtheupperEarlytolowerMiddleTriassic.ExceptionallylargecollectionsofthisammonoidfamilyfromNorthAmericaenablequantitativeand statistical analyses of its macroevolutionary trends. This study highlights that (1) the monophyletic clade ofAcrochordiceratidaefollowstheclassicalevolutetoinvoluteevolutionarytrend(i.e.increasingcoilingoftheshell);(2)thelineagealsoshowsaseeminglystepwiseincreaseofitsshelladultsize(shelldiameter);(3)thecladealsorecordsincreasingcomplexityofitssutureline;and(4)thelineageisalsocharacterizedbyaprominentincreaseoftheintraspecificvariationofitsshellmorphology,whichfollowstheBuckman’sLawofCovariation.

Thesemacroevolutionarytrendsarestatisticallyrobustandseemmoreorlessgradual.Furthermore,theycanbeconsideredasnon-randomwiththesustainedshiftofthemean,theminimumandthemaximumofstudiedshellcharacters.Suchre-sultisusuallyinterpretedasbeingtheeffectofaselectionpressureontheentirelineage,whichleadstoinferthepresenceofoneecologicalnichecommontoallspeciesofthismostlyanageneticlineagewithmoderateevolutionaryrates.

Increasinginvolutionofammonitesisusuallyinterpretedbyincreasingadaptationmostlyintermsofimprovinghydrody-namics.However,thistrendinammonoidgeometrycanbeexplainedasacaseofCope’srule(increasingadultbodysize)insteadofad hocfunctionalexplanationsofcoiling,becausebothshelldiameterandshellinvolutionaretwopossiblepathsforammonoidstoaccommodateincreasingbodysize.

REFERENCESBayer,U.&McGhee,G.R.1984:IterativeevolutionofMiddleJurassicammonitefaunas.Lethaia,17,1-16.Dommergues,J.L.1990.Ammonoids.In:McNamara,K.J.(ed.),Evolutionarytrends,BelhavenPress,London,162-187.Guex,J.1992:Originedessautsévolutifschezlesammonites.BulletindelaSociétéVaudoisedeSciencesNaturelles,82,117-

144.Haas,O.1942:RecurrenceofmorphologictypesandevolutionarycyclesinMesozoicammonites. JournalofPaleontology,

16,643-650.Jablonski,D.2000.Micro-andmacroevolution:scaleandhierarchyinevolutionarybiologyandpaleobiology.Paleobiology,

26(suppl.4),15-52.Schindewolf,O.H.1940.KonvergenzbeiKorallenundAmmoniten.FortschrittederGeologieundPalaeontologie,12,387-491.

Figure.EvolutionarytrendsrepresentedbylateimmatureshellgeometryandsuturelineforAcrochordiceratidaeduringtheAnisian

(MiddleTriassic).GlobalevolutionarytrendsaffectingsuccessivespectraofvariantsforAcrochordiceratidaeareincreasingadultshellsize,

increasinginvolution,increasingsuturecomplexity,andincreasingintraspecificvariability.(NextPage)

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6.13

Reinvestigation of the basal ray-finned fish Birgeria stensioei from the Middle Triassic of Monte San Giorgio (Switzerland) and Besano (Italy)

RomanoCarlo1&BrinkmannWinand1

1Paläontologisches Institut und Museum, Karl Schmid-Strasse 4, CH-8006 Zürich (carlo.romano@pim.uzh.ch; wbrink@pim.uzh.ch)

ThetwoearlierdescriptionsandapreviousreconstructionoftheMiddleTriassicactinopterygianBirgeria stensioeiaLdInGeR,1931fromtheBesanoFormationofMonteSanGiorgio(CantonTicino,Switzerland)andBesano(Lombardy,Italy)reliedeit-heronafewfragmentaryremainsoronasingleindividualonly.HerewepresentthefirststudyofB. stensioeithatisbasedonmultiplespecimensofthisbasalray-finnedfish.Sixty-sevenspecimenshavebeenexamined.

ThereinvestigationofB. stensioeiyieldednewinformationatgenusandspecieslevel.B. stensioeipredominantlydiffersfromtheotherspeciesofthegenusBirgeriasTensIö,1919inthearrangementofthebonesofthedorsalfinbase.Whileintheotherspeciesusuallytwoseriesofpterygiophoresarepresentthroughoutthedorsalfinbase,onlyoneseriesofpterygiophoresisdevelopedintheanteriorpartofthedorsalfinrootofB. stensioei.ThecaudalpeduncleandthecaudalfinlobesaremoreslenderandlongerthanillustratedinthepreviousreconstructionofB. stensioei(seescHwaRz1970).ThemorphologyofthecaudalpeduncleandfinaswellastheaforementionedspecialiseddorsalfinrootindicatethatpropulsionmighthavebeenmoreadvancedinB. stensioeicomparedtotheotherspeciesofthegenusBirgeria.B. stensioei isfurthermoredistinguishedfrommostoftheotherspeciesofBirgeriabythedegreeofossificationofthebraincaseandthepalatoquadrate.Asinmanyotherbasalactinopterygians,adermohyalisdevelopedinB. stensioeiandthisboneisprobablypresentintheotherspeciesofBirgeriaaswell.

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Terrestrial palaeoclimatical and palaeoenvironmental reconstructions in Northwestern Switzerland: carbon and oxygen isotope compositions of Early Oligocene and Late Pleistocene vertebrate remains.

ScherlerLaureline1,2,TütkenThomas3,BeckerDamien2&BergerJean-Pierre1

1Department of Geosciences, Institute of Geology, ch. du Musée 6, CH-1700 Fribourg (laureline.scherler@unifr.ch)2Section d'archéologie et paléontologie, Hôtel des Halles, CP64, CH-2900 Porrentruy3Steinmann Institute, University of Bonn, Poppelsdorfer Schloss, D-53113 Bonn

VertebrateremainsfromtwoEarlyOligocenelocalitiesoftheDelémontbasin (BeuchilleandPoillat)andfromeightLatePleistocenedolinefillingsoftheAjoieRegion(Courtedoux-VâTcheTchâandBoncourt-Grand'Combe)havebeenexcavatedalongtheTransjuranehighway(CantonJura,NorthwesternSwitzerland).Teethoflargemammalsandbonesofaquaticrep-tileshavebeenanalysedfortheirisotopecompositions(δ18O

CO3,δ18O

PO4,δ13C)inordertoreconstructthepalaeoclimaticaland

palaeoenvironmentalconditions.

ThetwoEarlyOligocenelocalitiesofBeuchilleandPoillatarelocatedintheJuraMolasse("Molassealsacienne"Formation)of the Delémont basin (Northern Switzerland). The presence of the smallmammal Blainvillimys avus and the ruminantIberomeryx minorallowsadatationtothemammalzonesMP23-24,around31.5to29.0Ma(Beckeretal.2004).Eightsamplesofreptilebones(crocodilesandturtles)aswellasfoursamplesofsympatricprimitiverhinocerotidteeth(Ronzotheriumsp.)havebeenanalysed.Thereptileboneshave lowδ18O

PO4values (from13.6‰to17.8‰) indicatingfreshwaterenvironments

(δ18OH2O

calculatedvaluesaveraging-6.15±1.03‰)whicharesupportedbythepalaeontologicalidentificationsoftheturtleremains(TrionyxandTestudinidae:freshwaterandterrestrialturtles,respectively).Asimilarδ18O

H2Ovalueof -6.18±1.5‰is

calculatedfromenamelδ18OPO4

values(18.3±1.3‰)oftherhinocerotidteeth,whichpresumablyreflectsthecompositionofmeteoricwater.Usingamodern-daymeanairtemperature(MAT)-δ18O

H2OrelationforSwitzerlandaMATof18.0±2.5°Cforthe

EarlyOligocenecouldbecalculatedandwasabout8-9°CwarmerthantodayintheCantonJura(RecentMATof8.7°C).Thisresultisinagreementwiththepalaeotemperatureof~17°CreconstructedfromfossilplantremainsintheEarlyOligoceneofCentralEuropebyMosbruggeretal.(2005).

TheeightLatePleistocenedolinefillingsofBoncourt-Grand'Combe(GC)andCourtedoux-VâTcheTchâ(VTA)arelocatedintheAjoieRegion(NorthwesternSwitzerland)andcorrespondmainlytoloessicandgraveldepositsassociatedwithfossilre-mains.Forty-sixteethoflargemammals(Equus germanicus, Mammuthus primigenius, Coelodonta antiquitatis, Bison priscus)havebeenanalysed:eightsamplesfromtheGCdolinefillingandthirty-eightfromthesevenVTAdolinefillings.Thesedimenta-ry series bearing the mammal remains trapped within the GC doline have been dated by OSL (Optically StimulatedLuminescence)toanageof~80kaBP.ThemammalremainspreservedwithinthesevenVTAdolineshaveallbeendiscoveredinthesamesedimentaryunitdatedtothetimeinterval45-40to35kaBP(latestMiddlePleniglacial)byOSLandradiocarbon(Beckeretal.2009).

Accordingtotheenamelδ13Cvalues,whicharesimilarinbothtimeperiods,thelargemammalslivedinaC3plant-domina-

tedenvironmentasindicatedbyvaluesrangingfrom-14.5‰to-9.2‰(O'Leary,1981).TheMATcalculatedfromtheδ18OPO4

valuesofthelargemammalassemblagefromtheGCdolineaverages6.0±4.6°C.TheMATcalculatedforthelargemammalassemblageoftheyoungerVTAdolinesaverages5.6±4.1°C,showingaquitesimilarclimate.Thislatterresultisconcordingwiththequantifiedecologystudyofthesmallmammalassemblagesofthesedolines,whichindicatespalaeotemperaturesaveraging 5°C (Oppliger, 2009). These palaeoclimatical values are about 3 to 4°C cooler than today in theCanton Jura.However,somevariationsintheδ18O

PO4valuesofthedifferentstudiedspeciesareobserved,andparticularlyintheVTAdo-

lines:forexampletheequidsshowslightlylowerδ18OPO4

values(13.09±0.8‰)thanthebovids(14.6±1.1‰).ThecalculatedMATafterspecificcalibrationscanthusbeverydifferent,rangingfrom2.2±2.8°CfortheEquusremainsto8.8±3.5°CfortheBisonremains,withavalueof5.8±3.3°CfortheCoelodontaand8.7±2.2°CfortheMammuthus.

Inordertounderstandthisbiasaprecisedsamplingofteethformedbeforeandaftertheweaningofthefoalshasbeendone.Itshowsthattheoxygenisotopiccompositionsarenotaffectedbythenursingperiodwhereasthecarbonisotopesshowslightlylowervalues.ThedifferencesinoxygenstableisotopecompositionswithintheseLatePleistocenemammalscouldthenbeenexplainedbythesamplingmethod,themammalphysiologyand/orecology,ortimeaveraging.ThedeterminationofapalaeotemperatureshouldbemorereliableduringtheOligocenewhentheclimatewasmuchmorestablethaninthePleistocenewhenbrutalclimaticalchangesoccurredveryfrequently.

WethanktheSectiond'archéologieetpaléontologieduJura,theUniversityofFribourgandtheSwissNationalFoundation(project115995)forfinancialsupport.

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yREFERENCESBecker,D.,Lapaire,F.,Picot,L.,Engesser,B.&Berger,J.-P.2004:Biostratigraphieetpaléoécologiedugisementàvertébrésde

LaBeuchille(Oligocène,Jura,Suisse).RevuedePaléobiologie,9,179-191.Becker,D.,Aubry,D.&Detrey,J.2009:LesdolinesduPléistocènesupérieurdelacombede"VâTcheTchâ"(Ajoie,Suisse):un

piègeàrestesdemammifèresetartéfactslithiques.Quaternaire,20,2,135-148.Mosbrugger,V.,Utescher,T.andDilcher,D.L.2005:CenozoiccontinentalclimaticevolutionofCentralEurope.PNAS,102,

14964-14969.O'Leary,M.H.1981:Carbonisotopesinphotosynthesis.BioScience,38,328-336.Oppliger, J. 2009: LamicrofaunedesdolinesduPléistocène supérieurde la combedeVâTcheTchâ etde la régionde

Boncourt(Ajoie,Jura,Suisse).Unpublishedreport,29pp.

6.15

How do recurrent patterns of covariation in molluscan shells connect to growth dynamics?

UrdySéverine1,GoudemandNicolas1,BucherHugo1andMonnetClaude1

1Paläontologisches Institut und Museum, Universität Zurich, Karl Schmid-Str. 4, 8006 Zürich (urdy@pim.uzh.ch).

Thecomparisonofshellshapeamongandwithindifferentcladesofmolluscscanbeinformativewithregardstothebasicrulesofaccretionarygrowth. Indeed,patternsofvariationofshell shapeand itsassociatedgrowthfeatures (likegrowthhalts)inammonoidsandgastropodssuggestthatcommonrulesofaccretionarygrowthunderliethemorphogenesisoftheshellanditsevolutioninbothclades(e.g.Bucher,1997;Checa&Jimenez-Jimenez,1997;Checaetal.2002).Moreover,insomephylogeneticallydistantammonoidsspecies,covariationsamongtheintensityofornamentation,thela-teralcompressionoftheapertureandthedegreeofwhorloverlaphavebeendescribed(Buckman’slaws).Ithasbeensugge-sted that simple growth rules could underlie these evolutionary recurrent patterns of covariation (Hammer & Bucher,2005a).Similarly,shellcharacterscovarywiththespacingbetweengrowthhaltsduringtheontogenyofsomeofthesehigh-lyvariableammonoidsspecies.Onegoalofthisstudyistoexplorewhetheracomparablepatternofcovariationistobefoundingastropodsaswell.Wealsowanttofindoutwhetherdocumentationofmodesofgrowthingastropodscouldsupporttheviewaccordingtowhichsomerecurrentpatternsofcovariationcouldreflectbasicconstraintstiedtoaccretionarygrowth.Anotherinterestistherelati-onshipamongshape,growthratesandage,apointthatisdifficult,ifnotimpossibletostudyonammonoids.Inthisstudy,weinvestigatetheontogeneticpatternsofcovariationamongapertureshape,intensityofornamentationandspacingbetweengrowthhaltsinapopulationofgastropods(Hexaplex trunculus,Muricidae)rearedundercontrolledlabora-toryconditions.Allindividualsoriginatedfromasingleeggmass.Wedescribethegrowthdynamicsoftheseindividualsfromtheageofapproximately100daysto550daysafterhatching.Thisstudyhighlightsacovariationamonggrowthrhythm,growthhaltsspacing,apertureallometryandintensityoforna-mentation:-Variationinshellshapeisanalysedbygeometricmorphometricsoflandmarkslocatedontheaperture.Wedocumentanontogeneticallometryofaperture,whichbecomesrelativelywiderwithsize.ThisisconsistentwithresultsobtainedusingellipticFourieranalysisofaperturecontourandtraditionalbiometrics.-Variationinthe‘strengthofornamentation’isrelatedtothemeanspacingbetweengrowthhalts:smoothersnailstendtoexhibitmorecloselyspacedgrowthhalts.Thiscovariation,asputinevidencehereinH. trunculus,seemsanalogoustothatobservedinsomehighlyvariableammonoidsspecies(e.g.Gymnotoceras rotelliformis,Amaltheus margaritatus).-Themeannumberofgrowthhaltspermonthisrelatedtotheglobalshapeofthegrowthcurveandtothemeanspacingbetweengrowthhalts:themorefrequentthegrowth‘pulses’,theshorterthetimespentonagrowthhalt(downtonearlycontinuousgrowth), themore linear thegrowthcurveandthesmaller thegrowthsegmentsbetweensuccessivegrowthhalts.Additionally,wedevelopagrowthvectormodel(Urdyetal.,2009)inordertosimulatetheformationofgrowthhaltspheno-menologically(Fig.1).Thismodelisabletoaccountforsomepatternsofcovariationamongspecimens.Inparticular,varia-tioningrowthrhythmisregardedascriticalingeneratingtheobservedcovariationbetweengrowthhaltsspacingandor-namentation.Basedonthesesimulations,wesuggestthatthiscovariationmainlyresultsfromsimplescalingamongtheaperturedimensionsandthelengthsofshellsegmentsbetweensuccessivegrowthhalts.Then,theimportantstructurationof phenotypic variation in some ammonoids species could be a generic outcome of underlying variation in growthrhythm.

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Figure1:Exampleofasimulationofgrowthhalts.

REFERENCESBucher,H.1997:Caractèrespériodiquesetmodedecroissancedesammonites:comparaisonaveclesgastéropodes.Geobios

MémoireSpécial,20,85-99.Checa,A.G.&Jimenez-Jimenez,A.P.1997:Regulationofspiralgrowthinplanorbidgastropods.Lethaia30(4),257-269.Checa,A.G.,Okamoto, T.&Keupp,H. 2002:Abnormalities asnatural experiments: amorphogeneticmodel for coiling

regulationinplanispiralammonites.Paleobiology28(1),127-138.Hammer,O.&Bucher,H.2005a:Buckman'sfirstlawofcovariation:acaseofproportionality.Lethaia38,67-72.Urdy, S.,Goudemand,N., Bucher,H.&Chirat, R. 2009:Allometries and themorphogenesis of themolluscan shell: a

quantitativeandtheoreticalmodel.JournalofExperimentalZoology,PartB(accepted).

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