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onCE FounD Almost EntirEly in thE wEstErn unitED stAtEs AnD illAsiA, DinosAur Fossils ArE now BEing DisCovErED on All sEvEn ContinEnts.A、host oF nEw rEvElAtions EmErgED in 1998 thAt promisE to rEshApE sCiEntists’ viEws oF DinosAurs, inCluDing whAt thEy lookED likE AnD whEn AnD whErE thEy livED、
it is DouBtFul thAt tyrAnnosAurus rEx hAD lips or thAt triCErAtops hAD ChEEks, sAys lAwrEnCE witmEr, An AssistAnt proFEssor oF AnAtomy At ohio univErsity inAthEns, ohio. witmEr wAs A lEADing rEsEArChEr For A stuDy on DinosAur AnAtomy thAt wAs prEsEntED At thE AnnuAl mEEting oF thE soCiEty For vErtEBrAtE pAlEontology, whiCh ConCluDED on oCtoBEr 3 in snowBirD, utAh.
witmEr’s stuDy rEAChED its ConClusions By using high-tECh ComputErizED AxiAl tomogrAphy (Ct orCAt) sCAns &long with CompArAtivE AnAtomy stuDiEs. For ExAmplE, thE thEory thAt triCErAtops AnD similAr DinosAur spECiEs hAD ChEEks wAs BAsED on pAst CompArisons with mAmmAls suCh As shEEp.But witmEr’s CArEFul AnAlysis FounD thE struCturE oF thE triCErA tops jAw AnD skull mADE it morE likEly thAt triCErAtops hAD A BEAk likE thAt oF An EAglE. witmEr sAiD thAt sCiEntists shoulD usE BirDs AnD CroCoDilEs As moDEls whEn rEsEArChing thE AppEArAnCE oF DinosAurs.
in EArly oCtoBEr sCiEntists AnnounCED thAt thEy hAD ConFirmED thE DisCovEry oF A nEw typE oF CErAtopsiAn DinosAur. thE DinosAur’s BonEs, FounD in nEw mExiCo in 1996, ArE ForCing pAlEontologists to rEthink thEir thEoriEs ABout whEn CErAtopsiAns migrAtED to whAt is now noAhAmEriCA、
sCiEntists prEviously thought thAt CErAtopsiAns, thE group thAt inCluDED thE wEll-known triCErAtops, ArrivED in northAmEriCA FromAsiA BEtwEEn 70 million AnD 80 million yEArs Ago.During this timE, thE lAtECrEtACEous pErioD, thE CAsh’s two supErContinEnts m lAurAsiA in thE north AnD gonDwAnAlAnD in thE south -- wErE in thE proCEss oF pulling ApArt, Cutting DinosAur populAtions oFF From EACh othEr AnD intErrupting migrAtory pAttErns.
thE FossilizED BonEs, FounD By Eight-yEAr-olDChristophEr wolFE AnD his FAthEr, pAlEontologistDoug wolFE oF thE mEsA southwEst musEum inArizonA, DAtE to ABout 90 million yEArs Ago. this CoulD mEAn thAt CErAtopsiAns originAtED in noAhAmEriCA AnD migrAtED toAsiA rAthEr thAn thE rEvErsE, pAlEontologists sAiD、Doug wolFE nAmED thE importAnt nEw spECiEs oF DinosAur zuniCErAtops ChristophEri AFtEr his son.
An ExpEDition From thE univErsitiEs oFAlAskA inAnChorAgE AnD FAirBAnks hAs DisCovErED A rEgion in rEmotE northErnAlAskA so riCh in FossilizED DinosAur trACks thAt tEAm mEmBErs DuBBED it thE "DinE ExprEsswAy". thE trAmplED ArEA wAs FounD During thE summEr oF 1998 onAlAskA’s noAh slopE nEAr thEBrooks rAngE.
thE tom FounD 13 nEw trACk sitEs AnD mADE CAsts From thE prints oF FivE DiFFErEnt typEs oF DinosAurs. thE roCk in whiCh thE prints worE FounD DAtEs to morE thAn 100 million yEArs Ago, or ABout 25 million yEArs olDEr thAn thE prEviously DisCovErED signs oF DinosAurs in thEArCtiC rEgion. pAlEontologists sAiD thAt thE nEw FinDings proviDE importAnt EviDEnCE thAt DinosAurs migrAtED BEtwEEnAsiA AnD noAhAmEriCA During thE EArly AnD miD-CrEtACEous pErioD, BEForEAsiA split oFF into its own ContinEnt.
two riCh Fossil sitEs in thE hills oFBoliviA hAvE BEEn rECEntly DisCovErED, ExCiting pAlEontologists AnD DinosAur BuFFs. this DisCovEry inCluDEs onE oF thE most spECtACulAr DinosAur trACkwAys ovEr FounD,
thE DisCovEry oF A lArgE sitE in thE mountAin rEgion oF kilA kilA in southErnBoliviA wAs AnnounCED in EArly oCtoBEr. hErE sCiEntists FounD thE trACks oF At lEAst two unknown spECiEs oF DinosAur. thEsE inCluDED A lArgE quADrupED ( Four-Foot ED) DinosAur thAt wAll proBABly ABout 20 m ( ABout 70 Ft) long.
thE othEr sitE, loCAtED not FAr From thEBoliviAn City oF suCrE, wAs unCovErED in A CEmEnt quArry By workErs sEvErAl yEArs Ago But wAs not Brought to pAlEontologist