中国东部地区新的数字两个问题的研究炳灵大夏巨龙中国早白垩世一新巨型蜥脚类恐龙 (英文)

中国东部地区新的数字两个问题的研究炳灵大夏巨龙中国早白垩世一新巨型蜥脚类恐龙(英文)

1erwellingratchiagesiin,laratch使用,u3000均有相关由来与喜剧喜剧的喜剧喜剧组不同，喜剧喜剧的喜剧性和喜剧性特征的喜剧性区域（李等人2006年，zhang等人2006年）和可构建物种（i类和椰子区域）之分，以及正下方的喜剧性和隐性区域（你等人2006年）一样，可通过区域一级到二级的碳灰岩区域（i类和二级），以及微带区域。就像这组一样，从一开始就应该报告女性未授权的二级微带（你等人2006年）、体生字母、短叶和高直隶。2“cer特性”DinosauriaOwen,1842SaurischiaSeeley,1887SauropodaMarsh,1878TitanosauriformesSalgado,Coria,andCalvo,1997Daxiatitangen.nov.TypeSpecies.G.binglingisp.nov.Etymology.“Daxia”(Chinese):nameofabranchoftheYellowRiverrunsalongtheLinxiaareaofGansuProvincewherethefossilswerediscovered.“Titan”(Greek):referstoGreekmythologicalgiants,symbolicofitsgreatsize.Diagnosis.Sameasforspecies.Daxiatitanbinglingisp.nov.Holotype.GSLTZP03-001:caudalmost10cervicalvertebrae,10dorsalvertebrae,twoproximalcaudalvertebrae,partialcervicalanddorsalribs,onehemalarch,rightscapula,rightcoracoid,andrightfemur.RepositedintheFossilResearchandDevelopmentCenter(FRDC)oftheThirdGeologyandMineralResourcesExplorationAcademyofGansuProvinceinLanzhou.Typelocalityandhorizon.SoutheasternpartoLanzhouBasin,GansuProvince,P.R.China;HekouGroup,LowerCretaceous(EditorialCommitteeofChineseStratigraphicStandard:Cretaceous2000).Etymology.“Bingling”(Tibetan):onehundredthousandBuddhas,referringtoBinglingTemple,afamousattractionneartheLiujiaxiaDamalongtheYellowRiver,about80kmsouthwestofLanzhou,thecapitalcityofGansuProvince.Diagnosis.DaxiatitanisabasalmemberofTitanosauria(definitionfollowingUpchurchetal[2004]astem-basedtaxondefinedasTitanosauriformesmorecloselyrelatedtoSaltasaurusthantoBrachiosaurusdistinguishedfromothersinhavingcervicalvertebraewhosecranialprezygapophysealarticularfacetsareoffsetcaudallysuchthatnonarticularbonecomprisesthecranialmostportionsoftheprezygapophysis;distalmarginofscapularbodyliesobliquerelativetoitslongaxis;femoraldistalcondylesbeveled~10°dorsolaterallywithrespecttofemoralshaft;andfemoraldistalcondylesdirectedcaudomedially-craniolaterallyindistalview.3攻击3.1sarticulate关于crini发/双c河道rou管理/双crafterracerace人sraftu-rerace人sraftu-rerace人sraftu-reracerace人sraftu-reracecicidinassitysu-rela也非价值,即criniol-roin-ro的u-la也非“criniol”国际计划以caudalmostrain军roTwentytwovertebrae,plusanumberofcervicaanddorsalribsandonehemalarch,arepreserved.A-mongthe22vertebrae,twoseriesarearticulated:acranialseriesof14andacaudalseriesoffive;thetwoserieswereseparatedbyashortgap.Theremainingthreeweredisarticulatedfromthecaudalendofthecaudalseries,butwererecoveredwithinafewmetersdistance.Thecranialmost10vertebraeinthecranialseriesarerecognizedascervicalsbasedonthecranioventralplacementoftheirparapophysesonthelateralsurfacesofthecentra.Thefollowingfourvertebraeinthissequencearethefourcranialmostdorsalswherethepositionsoftheparapophysesshiftrapidlyfromthecentrumtotheneuralarch.Theshortercaudalseriesofarticulatedvertebraecomprisesfourmiddledorsalsandonecaudaldorsal,wherethemiddledorsalspossessrelativelycraniocaudallongcentraandthecaudalvertebraiscraniocaudalshort.Oneofthethreedisarticulatedvertebraerepresentsanothercaudaldorsal;whiletheothertwoareproximalcaudalsbasedontheirprocoelouscentra.3.1.1srafterfici治理/案例Amongthepreservedterminal10cervicals,thecranialmostseven,whosemorphologiesaretypicalofmiddlecervicals,allhavecentrumlengthsgreaterthan66cm,andlacklateralfossaeontheircentra;whilethelastthreebearmorphologiesmoretypicalofcaudalcervicals,rapidlydecreaseinlengthfrom53cmto26cm,andpossesslateralfossae.Here,onlytheseventh-to-lastandsecond-to-lastcervicalsaredescribedindetailbecausetheyexemplifythemiddleandcaudalcervicalmorphologies,respectively,ofDaxiatitan.Theseventh-to-lastcervicalvertebra(Fig.1a)isthelongestofthepreservedseries,andrepresentswellthegeneralfeaturesofthemiddlecervicals.Its91cmlongcentrumisopisthocoelous.Thecranialarticularsurfaceishemispherical(23cminbothheightandwidth)andprominent(9cmlong);thecaudalarticularsurfaceisslightlylargerandmoreoblate,withaheightof31cmandwidthof28cm.Thelateralsurfaceofthecentrumissmooth,shallowlydepressedtowardthemidpoint,andbearsnofossaeorforaminae.Itsventrolateraledgesarewelldevelopedintoventrolaterallyprojectingridgesthatborderthehighlyconcaveventralsurfaceofthecentrum.Thecranialonethirdofthisridgemergesintotheparapophysis,themiddleone-thirdarchesdorsallyinlateralview,andthecaudalone-thirdbecomeshorizontalandprominentventrally.Theprezygapophysealalaprojectsslightlybeyondthecranialarticularsurface;itscranialmostendisformednotbytheprezygapophysealarticularsurfacebutbythecranialmostportionoftheprezygodiapophyseallamina.Thecentroprezygapophyseallaminaproceedsmoredorsallythanlaterallyfromthedorsolateralcornerofthecentrum.Incranialview,itsupperhalfbifurcatesintotwolaminae:themedialonesupportstheprezygapophysealprocessventrally,andthelateraloneconnectstotheventralsurfaceoftheprezygodiapophyseallamina.Theprezygapophyseaarticularsurfaceiselliptical(craniocaudallylong)slightlyconvex,andfacesdorsomedially.Indorsaview,asubstantialV-shapedgapseparatestheprezygapophyses,exposingroughlythecranialone-thirdothedorsalsurfaceofcentrum;accordingly,theabbreviatedintraprezygapophyseallaminaoccupiesonlythecaudalendoftheintraprezygapophysealspace.Theextensionsfromthediapophysistothecentrum,thepostzygapophysis,andtheribareallconnectedbylaminae.Thefuseddiapophysis-tuberculumiswidecraniocaudallyandobscuresthecranialcentrodiapophyseallaminainlateralview.Thecaudalcentrodiapophysealandpostzygadiapophysealconnectionssurroundashallowfossa.Thepostzygapophysisprojectsonlyasfarasthelevelofthecaudalsurfaceofthecentrum.Itissupportedventrallybyaverticalcentropostzygapophyseallamina.Correspondingtotheconditionseenintheprezygapophysis,thepostzygapophysealarticularsurfaceisslightlyconcave,andfacesventrolaterally.Theintrapostzygapophyseallaminadoesnotexist.Theshort,roughlyrectangular,caudally-projectingneuralspineliesoverthecaudalhalfofthecentrum.Itisverylowdorsoventrally,andseemsslightlylongercraniocaudallythanwidetransversely.Bothspinoprezygapophysealandspinopostzygapophyseallaminaearepresent.Thefusedribistetraradiate.Therod-likecranialprocessisshort,endingatthelevelofthecranialarticularsurface.Thecapitulumandthetuberculumarefusedtotheparapophysisandthediapophysis,respectively,anddivergeatanarrowangle.Thecostalprocessisnotpreserved,butanisolatedcervicalribfromthesamequarry,andtherefore,probablyattributabletothesameindividual,attainsalengthof290cm,spanningthelengthofatleastthreemiddlecervicals.Thecentrumofthesecond-to-lastcervicalvertebra(Fig.1b)ismuchshorter(39cm)thantheexemplarmiddlecervicaldescribedabove,butitsarticularsurfacesareslightlylarger.Unlikethemiddlecervicals,itscentrumbearsalargeanddeeplateralfossa.Thisfossaiselliptical,withitslongaxisrunninghorizontally,andspansalmostthewholelengthofthecentrum.Theribisnotfusedtotheparapophysis,whoseovateandventrolaterallyfacingarticularsurfaceislocatedaboutone-thirdthedistanceoftheventrolateraledgeofthecentrum.Theprezygapophysisisshort,anddoesnotprojectbeyondthecranialarticularsurface.Itsfacetisovateandfacesmoredorsallythanmedially.Thecentroprezygapophyseallaminaisnotbifurcate.Thediapophysisflaressharplyintoalaterallyfacing,dorsoventrallylongsurfacethatseemsfusedtothetuberculumofitsribatitsdistalend.Thediapophysisisalsosupportedbyrobustcranialandcaudalcentrodiapophyseallaminae.Aweakcaudodorsallydirectedspinodiapophyseallaminadividesthespacebetweenthepre-andpostzygodiapophyseallaminaeintoashallowcranialdepressionandadeepcaudalfossa.Therobustcentropostzygapophyseallaminasupportsthepostzygapophysis;thepostzygapophysealfacetisroundandflatandfacesalmostentirelyventrally.Thelowneuralspineislocatedmorecraniallythancaudallyabovethecentrum3.1.2DorsalvertebraeandribsTherighthalfofthethirddorsalvertebra(Fig1c)ispreserved.Itisopisthocoelous,withahemisphericalcranialarticularsurfacethatislessprominentthanthoseofthecervicals.Thelateralsurfaceothecentrumbearsadeeptriangularfossaonitscraniodorsalportion.Theparapophysishasmovedtothecranialedgeoftheneuralarch,fromwhichitsroundfacetfaceslaterally.Itishardtodistinguishthecranialcentroparapophyseallaminaandthecentroprezygapophyseallaminaventrally,buttogethertheyformatransverse,flatsheetofbonesupportingboththeparapophysisandtheprezygapophysis.Thecaudacentroparapophyseallaminaextendscraniodorsallyfromthemidpointofthedorsolateralmarginofthecentrumtomeettheparapophysis.Dorsally,theparapophysisconnectstotheprezygapophysisandthediapophysisviatwolaminae.Theprezygapophysealarticularsurfaceisflatandfacesdorsomedially.Theprezygapophysisisconnectedtothediapophysisbyastoutlamina.Thediapophysishasatriangulararticularsurfaceforitsrib,andissupportedventrallybyarobustcaudalcentrodiapophyseallamina.Thediapophysisisconnectedtothepostzygapophysisbyaverticallamina.Thepostzygapophysisissupportedventrallybyastoutcentropostzygapophyseallamina.Onlytherighthalfoftheneuralspineispreserved.Thespinoprezygapophyseallaminaislonganddistinct,butnospinopostzygapophyseallaminaexistsAtriangularprocessprotrudeslaterallyfromitscaudaend;thebaseoftheprocessisalsoconnectedtothedorsalsurfaceoftheshortpostzygapophysis.Theneuralspinedoesnotseemtobebifurcate.Incaudaview,therighthalfoftheshallowpostspinalfossaisfilledwithabouttenventrolaterallydirectedridges.Fourmiddledorsalsarearticulated.Thefirsttwo(Fig.1d)arefusedtooneanother,asarethelasttwo.Comparedtothecranialdorsals,themiddledorsalsaredorsoventrallytaller,theirlateralfossaearesmaller,andtheirparapophyseshavemigratedfartherupward,closetotheprezygapophysesanddiapophyses.Theparapophysealfacetsfaceventrolaterally,andthediapophysealfacetsbecomecraniocaudallylonganddorsoventrallynarrow.Nolaminaelinktheparapophysisanddiapophysis.Twocaudaldorsalvertebraearepreserved:one(fieldnumber:18-31)isarticulatedwiththemiddledorsals,andtheother(fieldnumber:18-15)(Fig.1e)isisolated.Theisolatedoneprobablyrepresentsthelastdorsalvertebrae.Theyaremorphologicallysimilartothemiddledorsalsdescribedabove;themostnotabledifferenceistheircraniocaudalshortening,placingtheparapophysisandthediapophysisinthesametransverseplane.Theneuralspineisalsocraniocaudallyshortandtransverselywide,withashallowmedianconcavity.Boththepre-andpostspinallaminaeareprominent.Isolated,largedorsalribsarepreserved.Inseveralofthem,theproximalendsareplanklike,andpossessdistinctfossae.Intheisolatedcaudaldorsal,ashortribisfusedtotherightsideoftheneuralarch.Asmall,ovalpneumaticforamenoccupiesamidlinepositionontheproximalportionoftherib.3.1.3在因变量和sqindexh-pcratventrole两物ventrole两物ventrole两物ventrole两物rolessitorityTwoproximalcaudalsarepreserved.Intherelativelywell-preservedsmallerone(fieldnumber:18-02)(Fig.1f),thecentrumisprocoelous,andafossaoccupiesthedorsalhalfofitslateralsurface.Thefossaisboundeddorsallybythetransverseprocessbutoccupiessomespaceonthelateralsurfaceoftheneuralarch.Thetransverseprocessisshort,ventrolaterallydirected,anddorsoventrallycompressed.Theprezygapophysealfacetsareovate,flat,andfacedorsomedially.Thepostzygapophysesareshort,andtheirfacetsfaceventrolaterally.Theneuralspineiscraniocaudallyshortandtransverselywide.Amedianprespinallaminaisseparatefromthelateralspinoprezygapophyseallaminae.Asingle,medianpostspinallaminarunsthedorsaltwo-thirdsofthecaudalsurfaceofthespine,buttheventralremainderdivergesintotwoshort,ventrolaterallydirectedlaminaethaterminateonthelateralsidesofthepostzygapophyseafacets.Nospinopostzygapophyseallaminaeexist.Acompletehemalarchispreserved(fieldnumber:18-13).Itistransverselynarrowanddorsoventrallylong.Itsproximalendsarebridged,enclosingahemalcanalthatoccupiesaboutone-fifththewholeproximodistallengthoftheelement.Thedistalportionpointsventrally,andistransverselyflatandslightlyenlargedcraniocaudally.3.2应用艺术系列3.2.1“双带头人”socinficiensventraft和tri能力sraftu2004Thecompleterightscapulocoracoidispreserved(Fig.2a).Itscomponentelementsaretightlyappressedbutnotfused.Thescapulahasacraniocaudally(proximodistally)long(101cm)bladeandadorsoventrallytall(78cm)acromialplate.Theplateiscraniocaudallyshort(57cm),andbearsadistinct,rounded,caudally-projectingprocessatitscaudodorsalcorner.Themedialsurfaceoftheplateisflat,butthelateralsurfaceislargelyconcave,withtheacromialcresboundingitscaudalmargin.Thisprominentcrestisorientedperpendiculartothescapularblade,andalsoformsthecaudaledgeoftheacromionprocess.Acranioventrallyorientedventral(lower)crestexistsventraltotheacromialplate,endsontheglenoid,anddemarcatesasmall,obliquesurfacebetweentheglenoidandtheblade.Mostoftheplateistransverselythin,buttheglenoidportiongreatlyincreasesinthickness(27cmatitsthickest).Theventraledgeothescapularbladeexpandstowardthedistalendwhilethedorsaledgeremainsparalleltothelongaxisofthescapularbody.Thedistaledgeofthescapularbodyisoblique,notperpendicular,tothelongaxisothescapularbody.Themedialsurfaceofthebladeisflat,whilethelateralsurfaceisslightlyconvex,bunotsoprominentlyastogivethebladeaD-shapedcrosssection.Thereappearstobeaweak,midlinecrestrunningalongthecranialendofthelateralsurfacethatendsatthejunctionofthetwocrestsofthescapularplate.Ventraltothisjunction,andonthecranialendalongtheventraledgeoftheblade,asmall,triangularprocessispresent.Thewholescapulabulgesslightlylaterally(outward).Thecoracoidiscraniocaudallyshort(46cm)anddorsoventrallytall(66cm).Itscranialanddorsalmarginsaregentlycurved,formingaroundedcraniodorsalcorner.Thecaudalmarginistightlyarticulatedtothescapula,andthesuturebetweenthemisroughlystraight,endinginV-shapedjunctionsatboththedorsalandventralends.Thecoracoidforamenislocatednearthemidpointalongthecaudaledgeofthecoracoid.Thecoracoidcontributeslesstotheglenoidthanthescapula.Thecoracoidportionoftheglenoidistransverselythick(23cm),andfacescaudoventrally;itoccupiesslightlymorethanhalfthelengthoftheventraledgeofthecoracoid,andprojectsoutward(ventrally)fromtherestofthecoracoid.3.2.2ralusalsixh国际习惯法Thecompleterightfemurispreserved(Fig.2b).Itis177cmlong,and58cmand57cmwideattheproximalanddistalends,respectively.Thefemurisstraight,craniocaudallycompressed,andtransverselywide.Thefemoralheadprojectsslightlydorsomedially,andsmoothlygradesintothegreatertrochanterlaterally.Thedorsalone-sixthofthelateraledgecurvesmedially.Thefourthtrochanterislocatedaboutthemidlength,nearthemedialmarginonthecaudalsurface.Twodistalcondylesarewelldeveloped,ofwhichthemedialprojectsmoredistallythanthelateral;therefore,thefemoraldistalcondylesbeveled~10°dorsolaterallywithrespecttofemoralshaft.Bothcondylesareexposedmorecaudallythancranially.Incaudalview,themedialcondyleisroughlysemicircularanddeflectedcaudomedially,whilethelateralcondylebearstwoverticalridges.Themedialridgeismorerobustthanthelateralandorientedcaudomedially,whileitslateralcounterpartisorientedcaudolat-erally.Thetwothussurroundawide,shallowgrooveTheflexorgroovebetweenthecaudalaspectsofthetwocondylesismuchdeeperthantheextensorgrooveonthecranialside.Incaudalview,thefemoraldistacondylesdirectedcaudomedially-craniolaterally.4caudalofrat是否为“scap”ElevenunambiguoussynapomorphiesofTitanosauriaarerecoveredbythiscladisticanalysis,andamongthemsevenarepresentinDaxiatitanandfourcannotbeevaluatedduetomissingdataintheonlycurrentlyknownspecimen.Thesevenunambiguoussynapomorphiesare:rudimentary,feeblydevelopeddiapophyseallaminaeofthecervicalvertebralarches(111:1);deepbutsimplelateralfossaeinthedorsalcentra(123:1);caudallyorientedneuralspinesinmiddleandcaudaldorsals,withtheirdistalendsapproachingthelevelofthediapophyses(149:1);ex-pandedventralendsofthecaudalcentrodiapophyseallaminaeinthecaudaldorsals(152:1);nofossaformedcaudaltothedeltoidcrestontheacromionportionofthescapula(210:0);unexpandeddorsaledgeofthescapularbody(parallelslongaxisofbody)(212:0);andflat,notD-shapedcrosssectionofproximalendofscapularbody(214:0).ThefourtitanosauriansynapomorphiesthatcannotbeevaluatedinDaxiatitanare:outsidepositionofthesubnarialforamenwithrespecttothenarialfossa(9:0);sixormoresacralvertebrae(156:3);absenceofaprominentproximolateralprocessonthehumerus(225:1);anddeeplyconcavedistocaudalsurfaceofthehumerusboundedbetweenprominentverticalridges(232:1).ThereareanothersixpotentialtitanosauriansynapomorphiespresentinDaxiatitan.ThesefeaturesoccurinDaxiatitan,butnotinBrachiosaurus;theirstatusinEuhelopusisuncertainduetolackofpreservation.Theseinclude:absenceoffossaeonthedorsalsurfacesoftheparapophysesofthecervicalvertebrae(110:0);spongyinternalconstructioninthecaudalcentra(162:1);opisthocoelousproximalcaudalcentra(168:2);ratioofproximodistallength:dorsoventralheightoftheproximalcaudalcentragreaterthan0.6(172:0);presenceofapostspinalfossaontheproximalcaudalvertebralarches(177:1);andpresenceofaventrallongitudinalsulcusontheproximalandmiddlecaudalcentra(187:1).AmongmembersoftheTitanosauria,DaxiatitanismorederivedthanEuhelopusinpossessingthreeunambiguoussynapomorphies:transverseprocesspositioneddorsaltotheparapophysisinthecaudaldorsals(153:1);ratioofmediolateralwidth:craniocaudallengthofcaudaldorsalneuralspinesgreaterthan1.0(widerthanlong)(154:1);andarticularsurfacesofthefemoraldistalcondylesexpandedontothecranialandcaudalportionsofthefemoralshaft(surfacesvisibleincranialandcaudalviews)(289:1).DaxiatitanislessderivedthanMalawisaurusandothermorederivedtitanosauriansinlackingthefollowingsevencharacters:absenceofhypantrum-hyposphenearticulationsonthedorsalvertebrae(126:0);presenceofaspinodiapophyseallaminaonthemiddleandcaudaldorsals(128:2);absenceofacaudalcentroparapophyseallaminaonthemiddleandcaudaldorsals(141:0);presenceofaprespinallaminaandabsenceofaspinoprezygapophyseallaminainnon-bifidneuralspinesofthemiddleandcaudaldorsals(143:1);caudaldorsalneuralspinesprogressivelyexpandingmediolaterallythroughmostoralloftheirlengths(“petal”or“paddle”shaped)(155:1);absenceofahyposphenalridgeontheproximalcaudavertebrae(178:0);andratioofhemalcanaldorsoventralheight:totalhemalarchlengthequaltoorgreaterthan0.30(202:1).5子阶段5.1wide-ga膜生态lietalThefemoraldistalcondylesofDaxiatitanareuniqueamongsauropodsbybeingdorsolaterallybeveledwithrespecttothefemoralshaft(Fig.4a)andcaudomedially-craniolaterallydirectedindistalview(Fig.4b).ThelattercharacterstronglyindicatesanoutwardorientationforthehindlimbsofDaxiatitan.Thisinferenceisfurthersupportedbytheexistenceofstronglyoutwardlyrotated,wide-gaugesauropodtrackwayspreservedinthesamegeologicalhorizon(theupperpartoftheHekouGroup)about50kilometersaway(Lietal2006;Zhangetal2006).ThefemoraldistalcondylemorphologyofDaxiatitancontrastssharplywiththeconditioninOpisthocoelus(Borsuk-Bialynicka1977),aderivedtitanosaurianfromtheLateCretaceousofMongolia,whosefemoraldistalcondylesaredorsomediallybeveled(Fig.4c)andcraniocaudallydirectedindistalview(Fig.4d).ThefemurofOpisthocoelushasbeenusedasamodelforfunctionalanalysisoftitanosaurianlocomotion,andtitanosaurianshavebeeninferredasthetrackmakersofwide-gaugesauropodtrackways(Wilson&Carrano1999).Thethreekeyfemoralcharactersdeemedresponsibleforwide-gaugelocomotionofOpisthocoelusweretheoutwardlyangledfemora,eccentricfemoralmidshaftcross-section,anddorsomediallybeveledfemoraldistalcondyles.ThefirsttwoarealsopresentinDaxiatitan,whiletheuniquefemoraldistalcondylemorphologyindicatesthatDaxiatitanrepresentsalineage-onethatevolvedearlyinthehistoryoftheclade-ofwide-gaugetrackmakerswithauniquemodeoflocomotion.5.2hefig显著提高cert法律3.4cert-lact3.3EuhelopusisanidealreferencetoestimatethepresacralvertebralnumberofDaxiatitanbecauseEuhelopus,likeDaxiatitan,isabasaltitanosaurianbutthesoleknownspecimenpreservesacompletepresacral(andsacral)vertebralcolumn.Euhelopushas31presacraland6sacralvertebrae(Wiman1929).The31presacralvertebraeconsistof19cervicals(Wedeletal2000)and12dorsals.Thecentrumlengthsfromcervicals15to19decreaserapidly(from266,203,180,142,to128cm,withadecreasingpercentagesof31%,27%,13%,and11%).Thecentrumlengthsfromcervical7to15changeslightly;cervical11isthelongest.Thelengthsofthecranialmostsixcervicalsrapidlyincreasecaudally.InDaxiatitan,thelastfivecervicalsalsorapidlydecreaseincentrumlengthcaudally;thenextpreserved,morecranialfivecervicalsretainsimilarcentrumlengthswithinanarrowmargin,apatternsimilartothatseeninEuhelopus.Therefore,wepredictthatDaxiatitanhadalongnecksimilartothatofEuhelopus.Thecervicalserieslength(cervicals2-19)oEuhelopusis4m,ofwhichthelastninecervicalsspanhalfthatlength(201cm)(Wedeletal2000)ThetotallengthofthelastninecervicalvertebraeoDaxiatitanis6.10m;assumingsimilarproportionstoEuhelopus,weestimatethetotalcervicalserieslengthofDaxiatitanat12.20m.InMamenchisaurushochuanensis,thesauropodwiththemostcompleteskeletaremainsknownfromChina,thecervicalserieslength(9.50m)is47%ofthetotalbodylength(20.18mOuyang&Ye2002).Ifthesameratioisused,Daxiatitanwouldbe25.91mlong,anditslifereconstructioncouldreach30mwhenaccommodatingthegapsbetweenvertebrae(Ouyang&Ye2002).DaxiatitanthereforecouldwellbethelongestknowndinosaurinChina;thepreviousrecordholder,Mamenchisaurussinocanadorum,wasestimatedas26mlongbasedonthelengthsofitscranialmostfourcervicals(Russell&Zheng1993).Inadditiontobeingpossiblythelongest,DaxiatitancouldalsobethelargestChinesedinosaurintermsofbodyvolumeandmass.ThearticularsurfacesofthecervicalcentrainDaxiatitanareroughlyhemispherical,andhaveahigharticularsurfaceareatocentrumlengthratios.Inthel