Paleontologists: Anomalocaris likely had thousands of eyes

Paleontologists: Anomalocaris likely had thousands of eyes

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A team of scientists have discovered that the Anomalocaris had 16,000 lenses in each eye.

Working on Kangaroo Island in South Australia, the team of scientists announced the discovery on Wednesday, saying that they have discovered that the predator had an astounding number of lenses in each eye.

Anomalocaris, one of the strangest and fiercest creatures from the Cambrian period, existed in a time when most multi-cellular life first evolved over 600 million years ago. The animals were about a meter long, and shaped as a flattened oval, similar to a modern flounder.

“The animal itself has been known for quite some time, but we’ve never known the detail of the eyes,” study researcher John Paterson, of the University of New England in Australia, told LiveScience. “It can tell us a great deal about how it saw its world and it also supports that it’s one of the key predators during the Cambrian period.”

“When you look at the animal it has these really gnarly looking grasping claws at the top of its head, for grasping onto its prey,” he added. “It used these grasping claws at the front to shove its prey into its circular mouth, which is also fairly fearsome looking.”

The team of scientists say they discovered a pair of fossilized eyes that show the beast had excellent vision. The exceptionally well-preserved fossil eyes for this Cambrian Period predator had acute vision that would rival or even exceed that of most living insects and crustaceans, scientists said. It is thought to have the best vision of any creature examined by scientists in recent memory.

The fossils represent compound eyes – the multi-faceted variety seen in arthropods such as flies, crabs and kin – and are amongst the largest to have ever existed. Each eye was about three centimeters across and contained more than 16,000 separate lenses, providing the the creature remarkable vision to support its predatory lifestyle, scientists said in a statement.

The number of lenses and other aspects of their optical design suggest that Anomalocaris would have seen its world with exceptional clarity whilst hunting in well-lit waters. Only a few arthropods, such as modern predatory dragonflies, have similar resolution.

The fossil record suggests this type of vision evolved before other animals – their prey – developed the armor-like defense of a hard exoskeleton, or legs for running away.

The existence of highly sophisticated, visual hunters within Cambrian communities would have accelerated the predator-prey ‘arms race’ that began during this important phase in early animal evolution over half a billion years ago.

“It would have been very aware of its environment. It would have been a very capable predator, especially when you compare it to other animals in the same fossil sites that wouldn’t have had as good of eyesight or could have even been blind,” Paterson said. “Anomalocaris would have had a distinct advantage, I think.”

Scientists said the discovery of powerful compound eyes in Anomalocaris confirms it is a close relative of arthropods, and has other far-reaching evolutionary implications. It demonstrates that this particular type of visual organ appeared and was elaborated upon very early during arthropod evolution, originating before other characteristic anatomical structures of this group, such as a hardened exoskeleton and walking legs.

The announcement comes just weeks after a new 3-D modeling of the mouth of Anomalocaris was released. Scientists said the research revealed evidence that the creature did not maintain hard-like teeth, but rather flexible teeth. The team of researchers said the discovery meant the create did likely did not consumer shelled creatures, which require more dense teeth.

No creature whose fossil dates to before the Cambrian period has eyes, the researchers say. Indeed, the discovery pushes the evolution of the compound eye much deeper into past than previous evidence suggested.

The international team behind this discovery includes two Adelaide researchers, Dr. Michael Lee (SA Museum and University of Adelaide – Environment Institute and School of Earth & Environmental Sciences) and Dr. Jim Jago (SA Museum and UniSA), and was led by Dr. John Paterson (University of New England).

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