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Researcherssaytheyhavediscoveredhowhumansgotteeth. TheresearchersarefromUppsalaUniversityinSweden. Theysaythathumanteeth "firstevolved 400 millionyearsago". Theybelieveourteethcamefromanancientfishcalledanacanthothoracid. Theresearchersstudiedafossilofthefish. Itwasdifficulttostudybecausethefishisencasedinrock. TheresearchershadtousethestrongestX-raymachineintheworldtoanalyseit. TheyusedtheX-raymachineto "digitallydissect" thefish. Theresearchersdiscoveredthatthefish'steethwereamazinglysimilartohumanteeth. Theresearchersalsosaidhumansand 60,000 speciesofjawedvertebrateslivingonEarthtodaycomefromthisfish.
Theresearcherssaytheacanthothoracidwasoneoftheearliestjawedvertebrateswithteethevertolive. Theywereveryexcitedatseeinghowsimilaritsteethweretoours. Aco-authorofthestudy, ProfessorPerAhlberg, said: "Thesefindingschangeourwholeunderstandingoftheoriginofteeth." Hecommentedonthesimilaritytothefish, saying: "Theirjawbonesresemblethoseofbonyfishandseemtobedirectlyancestraltoourown. Whenyougrinatthebathroommirrorinthemorning, theteeththatgrinbackatyoucantracetheiroriginsrightbacktothefirstjawedvertebrates." Anotherresearchersaid: "Nobodyexpectedtofindteethsodeepontheevolutionarytree."
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