Paleontologists have identified a new genus and species of fern-like plant from a single fossilized specimen collected in the New England region of New South Wales, Australia.

Keraphyton mawsoniae: (A) specimen before preparation; (B) general view of stem showing the 4 rib systems (Ia, Ib, IIa and IIb); (C) central segment and four fundamental ribs; (D) rib system Ib showing a short branch dividing into two equal ultimate ribs at right and a long branch producing at least three long ultimate ribs at left; (E) long branch of rib system IIa producing short ultimate ribs; (F) short branch of rib system IIa dividing into two ultimate ribs; (G) long branch of rib system IIb producing short ultimate ribs; (H) long branch of rib system Ia producing long, but broken, ultimate ribs. Abbreviations: cs – central segment, fr – fundamental rib, ic – inner cortex, oc – outer cortex, Lb – long branch, sb – short branch. Yellow arrowheads indicate ultimate ribs. (DH) are all oriented with the cortex of the axis towards the top of the photo. Scale bars – 500 μm, (B) – 2 mm. Image credit: Champreux et al, doi: 10.7717/peerj.9321.

The newly-discovered plant species lived approximately 360 million years ago (Devonian period) — a time when Australia was part of the supercontinent Gondwana.

“It is an extraordinary discovery, since such exquisitely-preserved fossils from this period are extremely rare,” said lead author Antoine Champreux, a PhD student at Flinders University.

“Plants and animals had just started to colonize continents, and the first trees appeared.”

“Yet while diverse fish species were in the oceans, continents had no flowering plants, no mammals, no dinosaurs, and the first plants had just acquired proper leaves and the earliest types of seeds.”

“Well-preserved fossils from this era are rare — elevating the significance of the new plant fossil.”

Named Keraphyton mawsoniae, the ancient plant shares some similarities with modern ferns and horsetails.

“We named the genus Keraphyton (like the horn plant in Greek), and the species Keraphyton mawsoniae, in honor of our partner Professor Ruth Mawson,” the researchers said.

The fossil was found in the 1960s by amateur geologist John Irving on the bank of the Manilla River in Barraba, New South Wales.

The specimen is a straight, 90-cm-long and 2 x 1-cm-wide portion of anatomically preserved stem.

It is characterized by a star-shaped vascular system with strands located at rib tips, and by a lack of secondary tissues.

There is no information on the lateral organs, their nature, size and arrangement in Keraphyton mawsoniae.

Nevertheless, it provides sufficient features to demonstrate its uniqueness and its affiliation to a new genus and species.

“It’s nothing much to look at — just a fossilized stick — but it’s far more interesting once we cut it and had a look inside,” Champreux said.

“The anatomy is preserved, meaning that we can still observe the walls of million-year-old cells.”

“We compared the plant with other plants from the same period based on its anatomy only, which provide a lot of information.”

Source: sci.news