Macrofossil evidence of early sporophyte stages of a new genus of water fern Tecaropteris (Ceratopteridoideae: Pteridaceae) from the Paleogene Redbank Plains Formation, southeast Queensland, Australia

Abstract

Rozefelds, A.C., Dettmann, M.E., Clifford, H.T. & Lewis, D., August 2015. Macrofossil evidence of early sporophyte stages of a new genus of water fern Tecaropteris (Ceratopteridoideae: Pteridaceae) from the Paleogene Redbank Plains Formation, southeast Queensland, Australia. Alcheringa 39,. ISSN 0311-5518.

Water fern foliage is described from the Paleogene Redbank Plains Formation at Dinmore in southeast Queensland. The material, which is based upon leaf impressions, records early sporophyte growth stages. The specimens occur at discrete levels in clay pits at Dinmore, and the different leaf stages present suggest that they represent colonies of young submerged plants, mats of floating leaves, or a mixed assemblage of both. The leaf material closely matches the range of variation evident in young sporophytes of Ceratopteris Brongn., but in the complete absence of Cenozoic fossils of the spore genus Magnastriatites Germeraad, Hopping & Muller emend. Dettmann & Clifford from mainland Australia, which are the fossil spores of this genus, it is referred to a new genus, Tecaropteris. The record of ceratopterid-like ferns adds significantly to our limited knowledge of Cenozoic freshwater plants from Australia. The geoheritage significance of sites, such as Dinmore, is discussed briefly.

Andrew C. Rozefelds [[email protected]], Queensland Museum GPO Box 3300, South Brisbane, 4101, Queensland, Australia and School of Earth Sciences, University of Queensland, St Lucia, 4072, Queensland, Australia; Mary Dettmann [[email protected]], H. Trevor Clifford [[email protected]] and Debra Lewis [[email protected]], Queensland Museum, GPO Box 3300, South Brisbane, 4101, Queensland, Australia.

Key words:

• Ceratopteris
• Tecaropteris
• Magnastriatites
• Pteridaceae
• Australia
• Cenozoic
• Paleogene
• Redbank Plains Formation
• Dinmore
• geoheritage

Acknowledgements

The authors thank the Directors, Drs Gordon Guymer of the Queensland Herbarium (BRI) and Kevin Thiele of the West Australian Herbarium for the loan of comparative material, and/or provision of photographs. We thank the Queensland Herbarium for allowing us to republish part of a figure from Andrews (1990), which was drawn by Margaret A. Saul. Advice on the literature and/or ecology of modern Ceratopteris was provided by Peter Bostock (Queensland Herbarium), Drs John Bradford and George Rogers (Palm Beach State College, Florida) and Leslie Hickok (University of Tennessee). Dr Patrick Brownsey (Te Papa Tongarewa, Museum of New Zealand) provided advice on sterility in ferns. Aquainox supplied samples of living Ceratopteris. Drs Andrew McMinn, Alan Partridge, Mike Macphail and Robin Helby provided advice on Curlew-1, Browse Basin palynology. Geoff Thompson, Queensland Museum provided the skilled support needed to photograph these faint impressions. Meg Lloyd (Queensland Museum) helped access some of the older literature. We thank two anonymous reviewers and the editor, Dr Stephen McLoughlin, for their helpful comments, which have improved this paper. Finally, we acknowledge all the collectors who contributed fossils from Dinmore to the museum, in particular Robert Knezour. Without their assistance this study would not have been possible.