An ancient animal called Auroralumina attenboroughii lived between 557 million and 562 million years ago.
The earliest known living animal relative, Auroralumina attenboroughii, is a relative of current jellyfish, according to a recent study.
The specimen, which bears Sir David Attenborough's name in honor of the renowned naturalist, explicitly refuted the notion that animal body designs were established during the Cambrian boom.
Jellyfish AsThe Oldest Relative of Living Creatures
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The specimen of Auroralumina attenboroughii is 20 centimeters long, or around the size of a typical toothbrush, as per Big Think.
The specimen features two distinct stalks that split off from a preserved section.
Each stalk has a dense crown of long, overlapping structures that the scientists have named tentacles at the top.
The researchers examined the specimen and thought about what might happen if a three-dimensional organism were forced onto a two-dimensional surface.
The researchers concluded that the left and right stalks were identical after taking this into account.
As a result, the specimen was probably tetraradial, or symmetrical around four corners that radiated outward from the center.
The jellyfish of today have the same trait.
The arrangement of the crown or the components within it could not be studied by the researchers because the specimen is preserved in a lateral view.
They found that the tentacles of living organisms are what these projections most closely resemble, however instead of being retained as separate tentacles, they seem to be one larger, composite structure.
Finally, the researchers concluded that the stalk and crown were made of distinct materials based on the variations in the fossil's preservation.
The crown was far less resilient and consisted of softer tissue than the hard stalks.
The fossil was cast by the researchers, and they utilized this cast to make a computer model of the monster so they could study it in various lighting conditions.
They then positioned it on a phylogenetic tree using its physical characteristics.
According to the research, Auroralumina attenboroughii belongs to the cnidarians' medusozoan stem group.
Cnidarians are a diverse and old phylum that includes corals and jellyfish and live in both the benthic and pelagic zones, as per Nature Ecology & Evolution.
Although cnidarians split from other animals in the Precambrian period, their record from the Ediacaran period (635-542 million years ago) is contentious.
They have a rich fossil record from the Phanerozoic eon that sheds light on the early history of the group.
Tens of millions of years before the Cambrian diversification of animal life, Auroralumina showed both the development of the crown group of an animal phylum and the fixation of its body plan.
There have been numerous reports of Ediacaran fossils with cnidarian affinity, possibly most notably Haootia, Corumbella, and Cloudina.
Molecular clocks reveal a Precambrian separation between the cnidarian lineages, with further radiations into the early Palaeozoic.
Deep-corner sulci and a polyhedral, perhaps tetraradial, tubicolous periderm are two characteristics that Auroralumina shares with these early Cambrian species.
The periderm is separated into two different parts, the stalk, and the cup, unlike the other groups, which are decorated and tapered.
The fact that the fossil isn't complete, meanwhile, suggests that Auroralumina may have only had its body partially annulated.
When compared to other fossil species, Auroralumina exhibited a unique mix of characteristics that sheds light on the early evolution of numerous important cnidarian properties and aids in resolving the phylogenetic affiliations of several extinct medusozoans.
Auroralumina is the oldest fossil that can be confidently attributed to the crown group of any living animal phylum and confirms the presence of crown-group cnidarians contemporaneous with the oldest assemblage of Ediacaran macrobiota.
Auroralumina disproved the common belief that animal body plans became fixed during the Cambrian Explosion by showing that at least one crown-group cnidarian body plan existed tens of millions of years earlier.
