Tomiostrobus

Tomiostrobus Temporal range: Early Triassic PreЄ Є O S D C P T J K Pg N ↓
File:Tomiostrobus australis.jpg
Fertile plant of Tomiostrobus australis from Early Triassic Gosford Formation near Terrigal, NSW, Australia.
Scientific classification
Kingdom:	Plantae
Division:	Lycopodiophyta
Class:	Isoetopsida
Order:	Isoetales
Family:	Isoetaceae
Genus:	†Tomiostrobus Retallack 1997
Species
Tomiostrobus australis Tomiostrobus polaris Tomiostrobus radiatus

Tomiostrobus is an extinct quillwort genus from the Early Triassic of Australia and Russia, which was especially widespread in the aftermath of Permian Triassic mass extinctions.

File:Isoetes and Tomiostrobus.jpg

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

File:Skilliostrobus australis juvenile.jpg

Juvenile plant of Tomiostrobus australis from the Early Triassic Newport Formation near Narrabeen, NSW

File:Skilliostrobus australis.jpg

Corm with root scars at base of fertile Tomiostrobus australis from the Early Triassic Gosford Formation near Terrigal, NSW

Description

Tomiostrobus australis is preserved as whole plants closely spaced within bedding planes, and lived as an early successional weed in lake and pond sedimentary environments, like living Isoetes. Unlike living Isoetes, Tomiostrobus formed closed cones with sporophylls that were distinctly shouldered and woody. This may have been an adaptation to heavy grazing by herbivorous therapsids.

See also

• Evolution of plants