Spriggina

Spriggina is a group of early animals from long ago. We do not know exactly how they are related to animals alive today. Fossils of Spriggina come from the late Ediacaran period in what is now South Australia. Spriggina floundersi is the official fossil symbol of South Australia and has only been found there.

This organism grew to be 3–5 centimetres (1.2–2.0 in) long and might have hunted other small things. Its underside had two rows of strong, fitting plates, and one row covered its top. The first few parts of its body joined together to make a “head.”

We do not know exactly what group Spriggina belongs to. Some think it might have been an annelid worm, a rangeomorph-like frond, a type of Charniodiscus, a proarticulatan, an arthropod (maybe related to the trilobites), or even a member of an extinct phylum. The group Spriggina once had three kinds—S. floundersi, S. ovata, and S. borealis—but S. ovata is now known as Marywadea ovata, and scientists are still talking about where S. borealis fits in.

Description

Spriggina was a small, early animal that lived a very long time ago. It grew to be about 3 to 5 centimeters long, about the size of a small pencil. Its body had many parts, or segments, that looked like rings.

On its back, Spriggina had overlapping plates, and on its belly, it had paired plates. The first two parts of its body formed something like a “head.” The very front part looked like a horseshoe and might have had something like eyes. The next part may have had something like antennae. We do not know much about its mouth or legs because they were not preserved in the fossils.

Discovery and naming

The genus was named after Reg Sprigg, who found the fossils of the Ediacara Hills in the Flinders Ranges in South Australia. He thought these fossils were from living things with many cells. Spriggina floundersi is the only widely accepted species in this genus. The name "floundersi" honors Ben Flounders, an amateur fossil hunter from South Australia. Another type, Spriggina ovata, is now placed in a different group called Marywadea.

Spriggina fossils come from a very old time called the Ediacaran period. Some fossils from the Vindhyan basin, about 1,650 million years old, were thought to be Spriggina, but they are likely just natural shapes made by tiny living things.

Spriggina had a strong body that did not turn to stone, which we can see from the way the fossils were formed.

Classification

The relationship of Spriggina to living animals is still unclear. It looks a bit like some modern worms, but it does not have certain features that would put it in that group. Some scientists have thought it might be related to an animal group called arthropods, which includes insects and spiders, because of its shape. However, newer studies show that Spriggina does not share enough special traits with arthropods to say for sure that it is one. This means its true place among living things remains a mystery.

Affinity

Scientists first thought Spriggina looked like a worm called Nereis. But when they looked closer, they saw it didn't match perfectly. In 1989, a scientist named Seilacher suggested Spriggina might be like a sea-pen.

Some people thought Spriggina might be related to arthropods because it looked a little like a trilobite from the Cambrian time. But Spriggina didn’t have limbs or an exoskeleton, so this idea was less likely.

South Australia’s fossil emblem

On February 14, 2017, Spriggina became the official fossil emblem of South Australia. This is because Spriggina has only ever been found in that area. The fossil is about 550 million years old. It was chosen in an online vote where many people from South Australia voted. It was selected to show the state's important geological and scientific history.