Emwadea microcarpa gen. et sp. nov.—anatomically preserved araucarian seed cones from the Winton Formation (late Albian), western Queensland, Australia

Abstract

Dettmann, M.E., Clifford, H.T., Peters, M., June 2012. Emwadea microcarpa gen. et sp. nov.—anatomically preserved araucarian seed cones from the Winton Formation (late Albian), western Queensland, Australia. Alcheringa, 217–237. ISSN 0311-5518.

A new genus and species, Emwadea microcarpa Dettmann, Clifford & Peters, is established for ovulate/seed cones with helically arranged cone scales bearing a centrally positioned, inverted ovule from the basal Winton Formation (late Albian), Eromanga Basin, Queensland. The cones are small, prolate ellipsoidal (9.5–14 mm vertical axis, 6.3–8.7 mm transverse axis) with wedge-shaped cone scales bearing winged seeds attached adaxially to the scale only by tissues surrounding the vasculature entering the ovule. Ovuliferous tissue that is free from the cone scale extends distally from the chalaza; the seeds' lateral wings are derived from the integument. Foliage attached to the cones is spirally arranged, imbricate and with spreading and incurved bifacial blades with acute tips; stomata are arranged in longitudinal files and are confined to the adaxial surface. The cone organization testifies to placement within the Araucariaceae, and is morphologically more similar to Wollemia and Agathis than to Araucaria.

Mary Dettmann [[email protected]] and Trevor Clifford, Queensland Museum, PO Box 3300, South Brisbane, Q 4101, Australia; Mark Peters, PO Box 366 Gumeracha, SA 5233, Australia. Received 31.3.2011; revised 23.8.2011; accepted 5.9.2011.

Key words:

• fossil conifer
• Araucariaceae
• seed cone
• late Albian
• Eromanga Basin
• Australia

Acknowledgements

We thank Andrew Rozefelds, Tasmanian Museum and Art Gallery, Hobart, Tasmania, Jan Allen, Royal Sydney Botanical Gardens, Mt. Tomah, New South Wales, Ross McKinnon, Brisbane Botanical Garden, Mt Coot-tha, Queensland, and Kerry Hanrahan, Forestry Plantations Queensland, Atherton, Queensland for comparative material of several living Araucariaceae. Ignacio Escapa and Ruth Stockey provided helpful comments that improved the quality of the original manuscript.