Notes on some Tasmanian Mesozoic plants. Part II.

This paper completes the examination, undertaken last year, of a series of fossil plants from the Mesozoic Rocks of Tasmania. In addition to the collections of the Tasmanian Museum and Geological Survey, I have also had the opportunity of examining a small collection from Mt. Nicholas, presented by Mr. Alex Montgomery to the Geological Survey of New South Wales. This list of thirty-three species indicates the extent to which the Tasmanian Mesozoic flora is now known, and compares favourably, as regards number of known species, with any of the floras of Mesozoic age in Australia

Notes on some Tasmanian Mesozoic plants. Part I.

Through the kindness of Messrs. Clive Lord and P. B. Nye I have been enabled to examine collections of Mesozoic fossil Plants from the Tasmanian and Launceston Museums and the Geological Survey of Tasmania. This has given me the opportunity of checking the determinations of some of these fossils made by the late R. M Johnston some thirty to forty years ago. Unfortunately. a large proportion of the specimens had lost their locality labels, but it is probable that one acquainted with the rocks in which these fossils occur in Tasmania could, with reasonable certainty, determine the localities from which the majority of the specimens came. The notes in this paper are not quite complete, but as many of the specimens were from the exhibition collections of the Tasmanian Museum, it was desirable that I should not keep them very long. In order not to delay publication of the results of my examination I have thought it advisable to present the following notes now, and hope, during next year, to be able to supplement this paper with another• short one, which should contain a few additional observations, together with some analysis of the Tasmanian Mesozoic floras, and comparison with the Mesozoic floras of the mainland and other areas

The diversity of Australian Mesozoic bennettitopsid reproductive organs

Several dispersed reproductive organs of bennettitopsid gymnosperms are described and illustrated from Triassic to Cretaceous strata of Australia: Williamsonia eskensis sp. nov. (Middle Triassic), Williamsonia ipsvicensis sp. nov. (Upper Triassic), Williamsonia durikaiensis sp. nov. (Lower Jurassic), Williamsonia sp. (Lower Jurassic), Williamsonia rugosa sp. nov. (Middle Jurassic), Williamsonia gracilis sp. nov. (Lower Cretaceous), Cycadolepis ferrugineus sp. nov. (Lower Jurassic), Cycadolepis sp. (Lower Cretaceous), and Fredlindia moretonensis Shirley 1898 comb. nov. (Upper Triassic). Among these, W. eskensis appears to represent the oldest bennettitalean reproductive structure yet identified. Although global floras expressed less provincialism during the Mesozoic and many genera are cosmopolitan, Australian bennettopsid species appear to have been endemic based on the morphological characters of the reproductive structures. Bennettopsids have a stratigraphic range of around 210 million years in Australia and are widely and abundantly represented by leaf fossils, but only around 20 specimens of reproductive structures, of which half are attributed to Fredlindia, have been recovered from that continent’s geological archive. The extremely low representation of reproductive organs vis-à-vis foliage is interpreted to reflect a combination of physical disintegration of the seed-bearing units while attached to the host axis and, potentially, extensive vegetative reproduction in bennettopsids growing at high southern latitudes during the Mesozoic.Other funding from:National Science Foundation (project #1636625)German Research Council (DFG KR2125/3)Friends of the Swedish Museum of Natural History (Riksmusei Vänner, Stockholm)SYNTHESYS (AT-TAF 467)</p

Macrofossil floras of the Latady Basin, Antarctic Peninsula

New collections of plant material from the Merrick and Sweeney Mountains provide further evidence of Jurassic floral diversity in the Antarctic Peninsula. Eighteen taxa are recognised, including sphenophytes (Equisetum), ferns (Cladophlebis, Sphenopteris, Coniopteris), Bennettitales (Otozamites, Zamites, Ptilophyllum, Dicytozamites, Williamsonia), conifers (Pagiophyllum, Brachyphyllum, Elatocladus), and other seed plants (Taeniopteris, Archangelskya, Pachypteris). Many of these species occur in floras from the Botany Bay Group (Early–Middle Jurassic), and other Late Jurassic to Early Cretaceous sites across the Antarctic Peninsula. The plant material from the Latady Basin occurs in two main associations with distinct floristic compositions that reflect local environmental and taphonomic conditions. The richest localities occur in the deltaic settings, where paleosoil and leaf litter layers are preserved. In contrast, relatively little plant material is found in the wholly marine units such as those from the Hauberg Mountains