The Jurassic flora of Western Australia

摘要

Jurassic plant remains in Western Australia are sparse but small assemblages of impression fossils have been deposited in the collections of the Australian Museum, Sydney, over the past century. They reveal the presence of ?Matoniaceae and Cladophlebis sp. from the Cockleshell Gully Formation (Toarcian–Aalenian), Zamites sp. from the Dingo Claystone (Middle to Upper Jurassic), and Elatocladus confertus (Oldham & Morris) Halle, Pagiophyllum amanguanus sp. nov., ?microsporangiate cones, Otozamites bengalensis Oldham & Morris, Otozamites linearis Halle, Otozamites sp. and Ptilophyllum cutchense Morris from the Yarragadee Formation (Late Jurassic). The assemblages show links to eastern Australian, Indian and Antarctic floras of Early Jurassic to Early Cretaceous age. The macrofloras generally support previous palynological dating of the host units, but also indicate broad (generic-level) similarities between Jurassic and Early Cretaceous floras across Gondwana. The macrofloras have no strong taxonomic or morphological signatures indicative of either aridity or humidity but the bennettitaleans have leaves intermediate in size between low and high latitude mid-Mesozoic assemblages, which favours previous palaeogeographic placements of Western Australia in the mesothermal middle-latitude province in the Jurassic.