Isoetes beestonii

Isoetes beestonii
Temporal range: Late Permian
Complete plant of Isoetes beestonii from latest Permian Coalcliff Sandstone in South Bulli Colliery, NSW, Australia.[1]
Scientific classification
Kingdom: Plantae
Division: Lycopodiophyta
Class: Isoetopsida
Order: Isoetales
Family: Isoetaceae
Genus: Isoetes
Species: †I. beestonii
Binomial name
†Isoetes beestonii
Retallack 1997

Isoetes beestonii is the oldest known species of the living quillwort genus from the latest Permian of New South Wales and Queensland. Originally considered earliest Triassic,[1] it is now known to be latest Permian in age, immediately after the Permian Triassic mass extinction.[2]

Reconstructions of sterile and fertile examples of Isoetes beestonii from the latest Permian Coal Cliff Sandstone of South Bulli Colliery, NSW, and of Tomiostrobus australis from the Early Triassic Gosford Formation near Terrigal, NSW

Description

Isoetes beestonii is preserved as whole plants in life position within bedding planes, and presumably lived as an early successional weed in lake and pond sedimentary environments, like living Isoetes. Its leaves were wider and more succulent than modern spacies of Isoetes.[1] Like modern Isoetes, fertile plants were little different from sterile plants, unlike Early Triassic Tomiostrobus which formed woody conelike fertile plants.

See also

References

  1. 1 2 3 Retallack, Gregory J. (1997). "Earliest Triassic origin of Isoetes and quillwort evolutionary radiation". Journal of Paleontology. 7 (3): 500–521.
  2. ↑ Retallack, Gregory J. (2013). "Permian and Triassic greenhouse crises". Gondwana Research. 24: 90–103. doi:10.1016/j.gr.2012.03.003.
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