A reconstruction of the oldest suspected predator ever found, with tentacles for grabbing the zooplankton of the era. Image Credit: BGS © UKRI
Sir David Attenborough has already been honored with the scientific names of over 40 species of plants and animals, living and dead. However, he might consider Auroralumina attenboroughii, a 560-million-year-old relative of corals and jellyfish, a particularly precious addition to his collection. Not only does it rewrite our ideas on early animal evolution, but it comes from near his boyhood haunts.
Charnwood forest, near Leicester, England has been a rich source of early fossils for 65 years. One of the oldest animals known, Charnia masoni, was found there in 1957 and revolutionized thinking about when complex life emerged.
Now, the same area has done it again, with the reporting in Nature Ecology and Evolution of the earliest known animal predator. Along with a species name honoring the great documentary-maker, the genus name means “dawn lantern” reflecting its resemblance to a burning torch from the beginning of time.
“It’s generally held that modern animal groups like jellyfish appeared 540 million years ago, in the Cambrian Explosion, but this predator predates that by 20 million years,” said one of the finders, Dr Phil Wilby of the British Geological Survey, in a statement. “It’s the earliest creature we know of to have a skeleton. So far we’ve only found one, but it’s massively exciting to know there must be others out there, holding the key to when complex life began on Earth.”
The impression of Auroralumina attenboroughii left on a rock in Charnwood forest: Image Credit: Simon Harris BGS © UKRI
Skeleton here does not mean possessing vertebrae like humans or fish. Instead, the creature discovered in the Charnwood rocks is a cnidarian, a phylum which today includes soft creatures like jellyfish but also corals.
Auroralumina is thought to have had a tough exoskeleton, like modern hard corals. It was around 20 centimeters (8 inches) long and topped by a crown of short tentacles thought to have been used to capture phytoplankton and emerging animal prey.
To find such early evidence of predatory behavior would be important enough, but Dr Frankie Dunn of the Oxford University Museum of Natural History, who led the study of the fossil explained its significance goes much further: “Most other fossils from this time have extinct body plans and it’s not clear how they are related to living animals. This one clearly has a skeleton, with densely packed tentacles that would have waved around in the water capturing passing food, much like corals and sea anemones do today.”
The lines on Auroralumina attenboroughii brought out for clarity, showing both its hard exo-skeleton and tentacles. Image Credit: Photograph: Simon Harris, Artwork: Rhian Kendall. British Geological Survey © UKRI
The authors’ working hypothesis is that A. attenboroughii was living in shallower waters than the other fossils found in the area – perhaps life was more active there.
“All of the fossils on the cleaned rock surface were anchored to the sea floor and were knocked over in the same direction by a deluge of volcanic ash sweeping down the submerged foot of the volcano, except one: A. attenboroughii,” Dunn said. “It lies at an odd angle and has lost its base, so appears to have been swept down the slope in the deluge.”
“When I was at school in Leicester I was an ardent fossil hunter. The rocks in which Auroralumina has now been discovered were then considered to be so ancient that they dated from long before life began on the planet. So I never looked for fossils there,” Attenborough said. “A few years later a boy from my school found one and proved the experts wrong. He was rewarded by his name being given to his discovery. Now I have – almost – caught up with him and I am truly delighted.”