Glossopteris
Glossopteris is probably the most familiar fossil leaf to non-paleobotanists.
The name Glossopteris is Latinized from two Greek words meaning
“tongue-fern”, referring to the elongated shape of individual leaves. Glossopteris
was not a true fern - it was a seed fern (a group of primitive gymnosperms)
(Plantae, Pteridospermophyta, Glossopteridopsida, Glossopteridales,
Glossopteridaceae). Glossopteris is reconstructed as a large
deciduous tree.
The Australian rock shown below is a commercial fossil
specimen with several hematite-stained leaf impressions of Glossopteris
browniana Brongniart, 1831 (or Glossopteris indica Schimper,
1874 - I’m not sure which one this is). Glossopteris species
taxonomy is notoriously convoluted, with >200 nominal species described
worldwide. During the Permian, Glossopteris-dominated forests
covered much of the ancient continent of Gondwana (= South America + Africa + Arabia
+ Antarctica + Madagascar + India + Australia).
Glossopteris has tremendous significance in the history of
geology. The modern-day geographic distribution pattern of Glossopteris
fossils was a key piece of paleontological evidence that Alfred Wegener used in
formulating his Continental Drift Hypothesis in 1915.
Stratigraphy: Illawarra Coal Measures, mid-Kazanian or Midian/Tatarian or Dzhulfian
Stage, Upper Permian.
Locality:
Dunedoo, Sydney Basin, eastern New South Wales, southeastern Australia.
Glossopteris leaves in hard deltaic claystone (field of view 12.4
cm across) from the Upper Permian of Dunedoo, New South Wales, Australia.
Wegener, A. 1915. Die Entstehung der
Kontinente und Ozeane. Braunschweig. F. Vieweg. 94 pp.
[English translation of 4th edition, 1966: The Origin of Continents and
Oceans. 246 pp.]