AsianScientist (Jun. 30, 2011) – Palaeontologists have uncovered half-a-billion-year-old fossils of compound eyes, confirming that primitive animals had excellent vision. This discovery was published today in the journal Nature.
An international team of scientists from the South Australian Museum and the University of Adelaide found the exquisite fossils, which look like squashed eyes from a recently swatted fly.
Modern insects and crustaceans have “compound eyes” consisting of hundreds or even thousands of separate lenses. They see their world as pixels: each lens produces a pixel of vision, and more lenses means more pixels and better visual resolution.
The fossil eyes were found on Kangaroo Island, South Australia and are 515 million years old. The eyes are amongst the largest to have ever existed, with each eye up to 3 cm in length and containing over 16,000 lenses. Only a few arthropods, such as modern predatory dragonflies, have similar resolution.
Sharp vision must therefore have evolved very rapidly, soon after the first predators appeared during the “Cambrian Explosion” of life that began around 540 million years ago.
As the fossil eyes were found isolated, it’s not certain what animal they came from, but they probably belonged to a large shrimp-like creature which needed excellent vision to support a predatory lifestyle.
The rocks containing the eyes also preserved a dazzling array of ancient marine creatures, including primitive trilobite-like creatures, armored worms, and large swimming predators with jointed feeding appendages, many of which are new to science.
The article can be found at: Lee M et al. (2011) Modern optics in exceptionally preserved eyes of Early Cambrian arthropods from Australia.
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Source: University of Adelaide.
Photo: John Paterson/University of New England; Thierry Laperousaz/South Australian Museum & Mike Lee/South Australian Museum/University of Adelaide.
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