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)...
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Veröffentlicht in: | Palaeobiodiversity and palaeoenvironments 2018, Vol.98 (1), p.71-95 |
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Sprache: | eng |
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Zusammenfassung: | 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. |
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ISSN: | 1867-1594 1867-1608 1867-1608 |
DOI: | 10.1007/s12549-017-0286-z |