Find might have come from ancient relative of today’s flowering plants
P. Hochuli and Susanne Feist-Burkhardt
Nubbly specks 243 million years old could be the oldest fossils of pollen grains yet found from close ancestors of today’s flowering plants.
The somewhat squashed spheres come from deposits dating from 3 million to 5 million years earlier than the previous record holders, says Peter Hochuli of the University of Zurich. The newly described fossils show some features of pollen grains more than 100 million years younger that are widely accepted as signs of flowering plants, or angiosperms, Hochuli says.
The pollen may have come from ancient near-relatives at the very stem of the angiosperm genealogical tree, Hochuli and a colleague say in the October Frontiers in Plant Science.
These fossils date from a poorly understood time in the history of flowering plants. Primitive seeds had already evolved in the ancestors of conifers and their relatives. Today’s flowering angiosperms form more-protected seeds coddled in botanical ovaries that ripen into fruits.
Widely accepted fossils from seed-pampering flowers don’t show up until starting roughly 139 million years ago. Yet DNA analyses often suggest angiosperms arose much earlier.
P.A. Hochuli and S. Feist-Burkhardt. Angiosperm-like pollen and Afropollis from the Middle Triassic (Anisian) of the Germanic Basin (Northern Switzerland). Frontiers in Plant Science. Vol. 4, Posted online Oct.. 1,2013, p. 344. doi: 10.3389/fpls.2013.00344.
J.A.Doyle. Molecular and fossil evidence on the origin of angiosperms. Annual Review of Earth and Planetary Sciences. Vol. 40, 2012, p. 301. doi: 10.1146/annurev-earth-042711-105313.
R. Ehrenberg. Floral Shocker: Blooms shake roots of flowering-plant family. Science News. Vol. 173, March 22, 2008, p. 182.