550 million-year-old creature mystery solved

A Dickinsonia fossil was first described in 1947.

Scientists believe that they have finally worked out what type of creature 'Dickinsonia' actually was.

Resembling a strange cross between a fungus, a lichen, a worm and a jellyfish, this peculiar organism was first described back in 1947 and has remained something of an enigma ever since.

Dickinsonia lived hundreds of millions of years ago on the sea floor and ranged in size from a few millimeters across to around half a meter. What's particularly intriguing about the species is that it was one of the earliest known organisms to move around rather than simply staying rooted to the spot.

Now a new study conducted by researchers from the universities of Oxford, Cambridge and Bristol, and the British Geological Survey has determined that Dickinsonia was most likely to have been an animal as oppose to a plant or a fungus.

The research involved analyzing the 'units' that run down the length of the creature's body and comparing them to those of other specimens to determine the rate of growth over time.

"When we combined this growth data with previously obtained information on how Dickinsonia moved, as well as some of its morphological features, we were able to reject all non-animal possibilities for its original biological affinity and show that it was an early animal, belonging to either the Placozoa or the Eumetazoa," said Dr Renee Hoekzema, a PhD candidate in Oxford University's Mathematical Institute.

"This is one of the first times that a member of the Ediacaran biota has been identified as an animal on the basis of positive evidence."

Dr Liu added: "This finding demonstrates that animals were present among the Ediacaran biota and importantly confirms a number of recent findings that suggest animals had evolved several million years before the "Cambrian Explosion" that has been the focus of attention for studies into animal evolution for so long.

"It also allows Dickinsonia to be considered in debates surrounding the evolution and development of key animal traits such as bilateral symmetry, segmentation and the development of body axes, which will ultimately improve our knowledge of how the earliest animals made the transition from simple forms to the diverse range of body plans we see today."