Yee-ha!: Trapping ring of the carnivorous fungus in 100 million-year-old amber from southwestern France.

Credit: Science/AAAS

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SYDNEY: A rare specimen of a fossilised fungus that used sticky 'lassoes' to ensnare and devour worms has been discovered in France.

The 100-million-year-old, microscopic fungus is delicately preserved in amber dug up from a deposit near Les-Nouillers in southwestern France. It is the oldest carnivorous fungus known and remains in pristine condition, which has allowed researchers to compare it with modern species.

"Amber research is important for the understanding of the evolutionary history of groups of micro-organisms that are otherwise rarely or not preserved in the fossil record," explained Alexander Schmidt, a palaeontologist from the Museum of Natural History in Berlin and lead author of a paper describing the fossil in the U.S. journal Science today.

Trap and digest

There are over 200 species of carnivorous fungi alive today, most of which are soil-dwelling. Some feed on microscopic nematodes – or roundworms – by using devices such as constrictive rings or adhesive structures to trap and incapacitate their prey.

The trapping devices are modified hyphae, which are filamentous branching structures. Under the microscope, the fungus found at Les-Nouillers has been observed to have hyphal rings 10 micrometres in diameter, which are likely to have produced a sticky secretion, improving the efficiency of trapping. Once trapped, roundworms would have been digested by a different type of hyphae.

According to Schmidt's team, the anatomy of the fossil species indicates that it's unlikely to be an ancestor of present day species, but rather an independent lineage that occupied the same ecological niche 100 million years ago.

"Fungi have vital ecological roles in modern ecosystems, as pathogens, predators and partners in mutualisms. It is very likely that these interactions with plants and animals have been around for a long time," said Tom May, senior mycologist at the Royal Botanic Gardens in Melbourne. "The fossil predatory fungus from amber is an important addition to the tantalising traces of fungi from the age of the dinosaurs and beyond."