Paleoecological study of the Cretaceous extremophilic flora with emphasis on xerophytes

Abstract

Thestudied materialcomesfromtheBohemianCretaceousBasin,Peruc-Korycany FormationCenomanianage,fromthelocalitiesPecínovandPraha-MaláChuchle. Recent plantswereusedforcomparisonwithfossilxeropyhteandmesophyteplants.Fossilandrecent materialwasmacromorphologicallydocumentedandanalyzedusingcuticularanalysis. Inthesystematic part, elevenfossiltaxafromdivisions Lyginopteridophyta, Cycadophyta,Ginkgophyta,Pinophytaand Magnoliophytaweredescribed.Fromthese,three newtaxawereestablished:bennetiteleafofZamitesmirovanaesp.nov.,angiospermleavesof Dicotylophyllumlabutae sp. nov.andD. pecinovense sp. nov. Based onthestudy of macro-and micro-morphology,it wasdistinguished whichpartofthestudied material belongstotheextremophytes.Observationsofmicromorphologyshowedthatplantsthatwere exposedto waterstress weretryingto overcome thisconstraint byadjustingtheir micromorphology. Analysingpreviouslypublishedandnewlyacquireddatahelpedtoseparatehalophytes fromotherstudiedfossiltaxa.Theseplantsfromtheenvironmentofsaltymarshesandtide- influencedswampsarecharacterisedbythickcuticle,stomataembeddedinstomatalchamber and/orsurroundedbyraisedrimsorpapillae.Theyshowvariousformsofwrinklesorpapillae ontheir externalsurface ofepidermisandarecomparativelyabundantin sediments ofthePeruc-KorycanyFormation.Theboundarybetween..