Mark A Purnell, UniversityofLeicester, DepartmentofGeology,Leicester,UK
Laurent P G Darras UniversityofLeicester, DepartmentofGeology,Leicester,UK
Surface Topography: Metrology and Properties, Journal Year: 2015, Volume and Issue: 4(1), P. 1 - 1

Published: Jan. 1, 2015

Anunderstandingofhowextinctanimalsfunctionedunderpinsourunderstandingofpast evolutionaryevents, includingadaptiveradiations,andtheroleoffunctionalinnovationand adaptationasdriversofbothmicro-andmacroevolution.Yetanalysisoffunctioninextinctanimalsis fraughtwithdifficulty.Hypothesesthatinterpretmolariformteethinfishesasevidenceof durophagous(shell-crushing)dietsprovideagoodexampleoftheparticularproblemsinherentinthe methodsoffunctionalmorphology.Thisisbecausetheassumedclosecouplingofformandfunction uponwhichtheapproachisbasedisweakenedby,amongotherthings,behaviouralflexibilityandthe absenceofaclearonetoonerelationshipbetweenstructuresandfunctions.HereweshowthatISO 25178-2standardparametersforsurfacetexture,derivedfromanalysisofwornsurfacesofmolariform teeth offishes,varysignificantlybetweenspeciesthatdifferintheamountofhard-shelledpreythey consume.TwopopulationsoftheSheepsheadSeabream(Archosargusprobatocephalus)werestudied. Thisfishisnotadietaryspecialist,andoneofthepopulationsisknowntoconsumemorevegetation andlesshard-shelledpreythantheother;thisisreflectedinsignificantdifferencesintheirmicrowear textures. TheArchosarguspopulationsdiffersignificantlyintheirmicrowearfromthespecialistshellcrusherAnarhichaslupus(theAtlanticWolffish).Multivariateanalysisofthesethreegroupsoffishes lendsfurthersupporttotherelationshipbetweendietandtoothmicrowear,andprovidesrobust validation oftheapproach.Applicationofthemultivariatemodelsderivedfrommicroweartexturein ArchosargusandAnarhichastoathirdfishspecies—thecichlidAstatoreochromisalluaudi— successfully separates wildcaughtfishthatatehard-shelledpreyfromlab-raisedfishthatdidnot.This cross-taxonvalidationdemonstratesthatquantitativeanalysisoftoothmicroweartexturecan differentiate betweenfisheswithdifferentdietsevenwhentheyrangewidelyinsize,habitat,andinthe structure oftheir trophicapparatus.Theapproachthushasgreatpotentialasanadditionaltoolfor dietary analysis inextantfishes,andfortestingdietaryhypothesesinancientandextinctspecies.

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