Major fossil discovery unearths more secrets about horsetail

'This is a significant discovery as horsetails are largely restricted to the northern hemisphere'

FASCINATING FIND: Queensland Museum's Dr Andrew Rozefelds (inset) was part of the team that discovered the new horsetail fossil south of Gladstone. Picture: Qld Mus

A FASCINATING discovery near Gladstone has brought to light new information regarding the lifespan an extinct plant.

Horsetails are a distinctive group of flora that are related to ferns and have hollow stems and small leaves arranged in regular whorls on their stems.

It was initially thought the plant became extinct in Australia over 90 million years ago - with the latest record of the plants found in Winton in western Queensland.

However in 2018, a team of scientists from the Queensland Museum and Central Queensland University found a fossil of a horsetail south of Gladstone.

The discovery meant the plant survived for at least another 50 million years after it was thought to be extinct.

CQUniversity associate professor Anita Milroy, who found the tiny specimen at the site, said it was initially dismissed as horsetail since there were no previous records of this group of plants from any fossil site of comparable age in Australia.

"This is a significant discovery as horsetails are largely restricted to the northern hemisphere and evidence of this group in the southern hemisphere has been missing," Prof Milroy said.

"This had led to the assumption that Australia played no role in the evolution of the group.

"The new Australian fossils and recently described fossils from New Zealand show that this is incorrect."

Queensland Museum acting head of biodiversity and geosciences Dr Andrew Rozefelds said the new discovery indicates the plants were still growing here 40 million years ago.

"This fossil provides the youngest evidence of this plant group from Australia revealing a significantly longer and more complex history than previously thought," Dr Rozefelds said.

"It will play a key role in understanding the history and past distribution of horsetails in Australia, but the challenge is to assemble and characterise the traits of these living and fossil plants to better understand the origins and history of this remarkable group."

Dr Rozefelds also said the discovery was unexpected and more research will provide additional and surprising insights into the history of modern Australian flora.

The group's full findings have been published in the latest edition of the Australian Systematic Botany journal.

Originally published as Major fossil discovery unearths more secrets about horsetail