Rhabdotaenia – a typical Gondwanan leaf from the upper Permian of Jordan

Abstract

Rhabdotaenia, a typical leaf type of Gondwana (e.g., India, Australia, Africa, South America) is described from the Umm Irna Formation (Permian) of the Dead Sea Region, Jordan. Two fragments with well-preserved cuticles were collected during fieldwork in 2017 from a single locality. They are characterized by a taeniopterid morphology and sparsely anastomosing veins. Veins arise from the rachis at acute angles of about 45°, immediately dichotomize and recurve slightly to run at about 80° to the rachis straight towards the margin, sporadically dichotomizing a second time and forming sparse anastomoses. Epifluorescence microscopy revealed that stomata are confined to intercostal fields and are haplocheilic with exposed guard cells surrounded by only poorly differentiated subsidiary cells. Ordinary epidermal cells are characterized by slightly sinuous cell walls within intercostal fields. The new material is the northernmost occurrence of this genus reported so far, well within the palaeoequatorial belt of Pangea. This occurrence highlights the floral relationship of some assemblages of the so called ‘mixed floras’ of the Arabian Peninsula with Gondwana, and demonstrates that the Umm Irna Formation, in particular, still holds great potential for future palaeobotanical discoveries.

Patrick Blomenkemper [[email protected]], Paläobotanik, Westfälische Wilhelms-Universität, Heisenbergstraße 2, 48149 Münster, Germany; Hans Kerp [[email protected]], Paläobotanik, Westfälische Wilhelms-Universität, Heisenbergstraße 2, 48149 Münster, Germany; Abdalla Abu Hamad [[email protected]], University of Jordan, Queen Rania St, 2V7F + 85 Amman, Jordan; Benjamin Bomfleur [[email protected]], Paläobotanik, Westfälische Wilhelms-Universität, Heisenbergstraße 2, 48149 Münster, Germany.

Key Words:

• Taeniopteris
• Glossopteridales
• cuticle analysis
• mixed flora
• Lopingian
• Jordan

Acknowledgements

The authors wish to thank the University of Jordan (Amman) for support; Yahia S., Nidal S. and Haatem S. Badandi (Irbid, Jordan), Frank Scholze and Jörg W. Schneider (Freiberg, Germany), Sebastian Voigt (Thallichtenberg, Germany) for field-work assistance, and Ashwini Srivastava and Stephen McLoughlin for their helpful comments that improved an earlier version of the manuscript and additional literature acquisition. Funding: Financial support was provided by the German Science Foundation (DFG Emmy Noether grant BO3131/1–1 ‘Latitudinal Patterns in Plant Evolution’ to B.B.; DFG grants KE584/11–1 + 2 and KE584/20–1 to H.K.). Abdalla Abu Hamad wishes to thank the DFG for his stay in Germany.

Disclosure statement

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