Mesozoic - Mesozoic - Pangaea forms and breaks up Pangaea forms and breaks up The basic nature of modernThe basic nature of modernterrestrial ecosystems wasterrestrial ecosystems wasestablished no later than by theestablished no later than by theend of the Paleozoic Eraend of the Paleozoic EraThe 200 my intervalThe 200 my intervalencompassed by the encompassed by the MesozoicMesozoicEraEra and the first part of the and the first part of theCenozoic saw the most dramaticCenozoic saw the most dramaticchanges in world vegetation,changes in world vegetation,flora, and fauna, the rise offlora, and fauna, the rise ofplant-animal interactions, andplant-animal interactions, andthe two greatest extinctionthe two greatest extinctionevents in the history ofevents in the history ofterrestrial ecosystems (Permian-terrestrial ecosystems (Permian-Triassic boundary, K-TTriassic boundary, K-Tboundary)boundary)Extinct Land Plants - the Fossil RecordThe greatest massThe greatest massextinction of all timesextinction of all timesmarks the boundarymarks the boundarybetween the Paleozoicbetween the Paleozoicand Mesozoic (theand Mesozoic (thePermian and Triassic)Permian and Triassic)•• 90% of marine life 90% of marine life•• 50% of terrestrial 50% of terrestrialtetrapodstetrapods••20% of land plants20% of land plants(including Cordaites(including Cordaitesand most Glossopterids)and most Glossopterids)Extinct Land Plants - the Fossil RecordScience 15Apr2005Extinct Land Plants - the Fossil RecordTriassic Period (245 - 208 mya)Triassic Period (245 - 208 mya)Pangaea - early TriassicMaximum development of Maximum development of PangaeaPangaeawith highly seasonal climateswith highly seasonal climatesMore cosmopolitan floras again -More cosmopolitan floras again -Tethys Sea no longer a major factorTethys Sea no longer a major factorTriassicExtinct Land Plants - the Fossil RecordDinosaurs arose in the lateDinosaurs arose in the lateTriassic from thecodontTriassic from thecodontreptiles.reptiles.The first true dinosaursThe first true dinosaurswere the ceratosaurians,were the ceratosaurians,or horned dinosaurs.or horned dinosaurs.PlateosaurusPlateosaurus (larger) spies two (larger) spies two YaleosaurusYaleosaurus (left) and a (left) and asmaller smaller CoelophysusCoelophysus behind. Note the dominant behind. Note the dominantvegetation type of Cycads (vegetation type of Cycads (Bjuvia).Bjuvia).Extinct Land Plants - the Fossil RecordTriassic Period (245 - 208 mya)Triassic Period (245 - 208 mya)The Triassic (andThe Triassic (andJurassic) is known as theJurassic) is known as the““Age of CycadsAge of Cycads”” as this as thisgymnosperm groupgymnosperm grouprapidly diversified afterrapidly diversified afterinitially appearing earlierinitially appearing earlierin the Permian.in the Permian.Modern cycad - DioonExtinct Land Plants - the Fossil RecordPlateosaurusPlateosaurus (larger) spies two (larger) spies two YaleosaurusYaleosaurus (left) and a (left) and asmaller smaller CoelophysusCoelophysus behind. Note the dominant behind. Note the dominantvegetation type of Cycads (vegetation type of Cycads (Bjuvia).Bjuvia).Triassic Period (245 - 208 mya)Triassic Period (245 - 208 mya)Other elements of this cosmopolitan Triassic flora:Other elements of this cosmopolitan Triassic flora:The glossopterids persisted inThe glossopterids persisted inGondwana but were graduallyGondwana but were graduallyreplaced by a new florareplaced by a new floracharacterized by the seed fern,characterized by the seed fern,DicroidiumDicroidium. By the close of the. By the close of theTriassic the glossopterids wereTriassic the glossopterids wereextinct.extinct.DicroidiumDicroidium sp. from New sp. from NewSouth Wales, AustraliaSouth Wales, AustraliaSeed fernsSeed fernsExtinct Land Plants - the Fossil RecordTriassic Period (245 - 208 mya)Triassic Period (245 - 208 mya)Other elements of this cosmopolitan Triassic flora:Other elements of this cosmopolitan Triassic flora:Primitive conifers andPrimitive conifers andginkgoesginkgoesThe big trees of theThe big trees of theTriassic wereTriassic wereprimitive lineagesprimitive lineagesof conifers andof conifers andginkgoesginkgoesExtinct Land Plants - the Fossil RecordTriassic Period (245 - 208 mya)Triassic Period (245 - 208 mya)Other elements of this cosmopolitan Triassic flora:Other elements of this cosmopolitan Triassic flora:Primitive conifers andPrimitive conifers andginkgoesginkgoesThe The Petrified Forest NationalPetrified Forest NationalPark during the late Triassic,Park during the late Triassic,(225 mya)(225 mya)The gymnosperms replacedThe gymnosperms replacedlycopsids and sphenopsidslycopsids and sphenopsidswhich were reduced in sizewhich were reduced in sizeand diversityand diversityAraucarioxylonAraucarioxylon, largest and, largest andmost abundant of the park'smost abundant of the park'sfossil conifer trees, towersfossil conifer trees, towersover the horsetailover the horsetailNeocalamitesNeocalamitesExtinct Land Plants - the Fossil RecordTriassic Period (245 - 208 mya)Triassic Period (245 - 208 mya)Other elements of this cosmopolitan Triassic flora:Other elements of this cosmopolitan Triassic flora:Primitive conifers andPrimitive conifers andginkgoesginkgoesThe The Petrified Forest NationalPetrified Forest NationalPark todayPark todayAraucarioxylon Araucarioxylon represents onerepresents oneof a number of extinct generaof a number of extinct generaof the extant araucariadsof the extant araucariadsplaced in Araucariaceae (nowplaced in Araucariaceae (nowstrictly Southern Hemisphere)strictly Southern Hemisphere)that comprise the petrifiedthat comprise the petrifiedrocks in Arizona - morerocks in Arizona - morecosmopolitan in Mesozoiccosmopolitan in MesozoicExtinct Land Plants - the Fossil RecordTriassic Period (245 - 208 mya)Triassic Period (245 - 208 mya)Other elements of this cosmopolitan Triassic flora:Other elements of this cosmopolitan Triassic flora:““ModernModern”” families of families offernsfernsNew lineages of primitive and advanced fernsNew lineages of primitive and advanced ferns(with an (with an annulusannulus) are seen in the understory) are seen in the understoryannulusExtinct Land Plants - the Fossil RecordTriassic Period (245 - 208 mya)Triassic Period (245 - 208 mya)Other elements of this cosmopolitan Triassic flora:Other elements of this cosmopolitan Triassic flora:““ModernModern”” families of families offernsfernsThese include:These