Yarravia oblongaLang & Cookson, 1935 emended, from the Lower Devonian of Victoria, Australia

Abstract

Yarravia oblonga is emended here and adds to our knowledge of floral diversity during the late Silurian and Early Devonian of central Victoria, Australia. Examination of specimens and analysis with light microscopy have revealed its defining characteristics as a slender elongate fructification, with most of the dichotomies in the fructification confined to the sterile axes. The sporangia of Y. oblonga are located centrally with sterile axes on the outside curving up and over the apices. The original diagnosis of a synangium is discounted as it was an artefact of preservation, and Hedeia is now considered a heterotypic synonym of Yarravia, with the latter taking priority. Furthermore, the branching pattern of Yarravia is simple and demonstrates that it does not belong with the ‘trimerophyte grade’. The presence of Yarravia in South China is of palaeophytogeographical importance, as it suggests some exchange between the two regions or is evidence of convergent evolution.

Fearghus R. McSweeney* [[email protected]] School of Science, RMIT University, Swanston Street, Melbourne 3000, Australia; Jeff Shimeta [[email protected]] School of Science, RMIT University, Swanston Street, Melbourne 3000, Australia; John St. J. S. Buckeridge [[email protected]] Earth & Oceanic Systems Group, RMIT University, GPO Box 2476, Melbourne, Australia.

Keywords:

• taxonomy
• early land plants
• Hedeia
• Yarravia

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Acknowledgements

We thank Museums Victoria and especially the Vertebrate Palaeontology Collections Manager Tim Ziegler for facilitating access to their collection of Hedeia and Yarravia and for organizing the use of the M205 C Leica microscope to photograph the specimens. The staff at the Baillieu Library, the University of Melbourne, for facilitating access to Dr J. Tims’ PhD thesis. Dr Michael Garratt for his help in Yea area. Mrs Peggy Laid for access to her property on Ghin Ghin Road and donating a specimen, Prof. Dianne Edwards and Dr J Tims for donating specimen NMV P256741, and Clem Earp in corresponding with F. McSweeney on specimens he collected in the Alexandra area. Prof. Christopher J. Cleal (National Museum Wales) in corresponded on nomenclature. Finally, thanks to two anonymous reviewers and the Editorial Board of Alcheringa for their insightful feedback.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by an Australian Government Research Training Program Scholarship.