Newly Discovered 16-Million-Year-Old Moth-Like Fossil Is First-Of-Its-Kind

Researchers in Australia have unearthed a well-preserved fossil of what they believe is a 16-million-year-old sawfly. The fossil's condition surprised the researchers, as they could even see the pollen grains that the insect feasted on, IFL Science reported. It is a rarity that a fossil survives so well, for such a long period.

The sawfly found in the fossil is the first of its kind discovered on Earth. This new species has been extinct for millions of years in the world. According to available data, the species flew around what is now Australia in the Miocene Period. Findings regarding the discovery have been published in Systematic Entomology.

Sawflies

Sawflies despite their name are members of the wasp family rather than the fly family, Earth reported. Spitfires are the closest to Sawflies, in terms of physical features. The insects were given the name 'sawfly' because of their saw-like ovipositor, a part they used to lay eggs. Sawflies look similar to flies, but cannot be categorized as such because of the lack of  “wasp waist.”

Discovery of the Fossil

The fossil was located by a group of paleontologists in central New South Wales, Earth reported. This project team had experts from  CSIRO, the University of Canberra, the Australian Museum, and the Queensland Museum. The discovery took place in 2018 when the team was exploring McGraths Flat, a fossil-rich site, which has yielded many other similar findings, over the years.

The team analyzed the fossil’s wing venation and other preserved features, to understand the preserved insect. They concluded, that the insect is a new species of sawfly.

"We looked at the fossil and its morphology and then put this information together with molecular and morphological data from a wide sample of current sawfly species. This helped us decipher the fossil’s placement in the sawfly tree of life," explained lead author, Juanita Rodriguez, a research scientist at CSIRO. The species was estimated to be 11 to 16 million years old from the Miocene Period.

Naming of the New Species

The research team collaborated with the Mudgee Local Aboriginal Land Council and named the new species Baladi warru using Wiradjuri words. This collaboration was done because the fossil was discovered on the land of the Wiradjuri people. 'Baladi' translates to "saw" and  "warru" means "wasp" in the aboriginal tribe's native language. The new species has allowed researchers to gain more insights into the evolutionary history of sawflies.

Tracing the Origin of Sawfly

The fossil helped researchers in understanding the development and adaptation that had facilitated within sawflies across centuries, Earth reported. The age and positioning of the fossil revealed to the experts that the insect originated during the Cretaceous Period, about 100 million years ago. The ancient ancestors of sawflies lived in Gondwana and after the splitting of the supercontinent spread across regions that would become Australia and South America.

Pollen in the Fossil

Researchers detected pollen grains on the head of the sawfly, Earth reported. The team used this finding to find out how the new species interacted with the Miocene environment. "When we examined the fossil, we identified pollen grains on the sawfly’s head which revealed it had visited a flowering Quintinia plant. This helped our team trace complex species interactions in the palaeoenvironment of McGraths Flat," Rodriguez said.

This further implied that the species had the mechanism to feed on toxic plants. "They eat the leaves of Myrtaceae – a family of woody plants that includes eucalypts – because they have mouthparts with which they can separate toxic oils or a chemical detoxification system inside their gut when feeding on myrtaceous leaves. This enables the larvae, sometimes called spitfires, to use the oils as a defensive weapon," explained co-author Michael Frese, a paleontologist at the University of Canberra. 

Valuable Insights

Researchers believe that the discovery would aid experts in the future, to analyze the role of this species as pollinators, Earth reported. They want more studies to understand how sawflies adapted to various environments and changed their dietary preference, as per requirement.

"Although this particular species, Baladi warru, has been extinct for millions of years, it provides information on native pollinators so we can understand their evolution and impact in the present," Frese concluded.