Complex eyes with modern optics from an unknown arthropod, more complex than trilobite eyes, have been discovered in early Cambrian strata from southern Australia. The exquisitely-preserved imprints of the eyes in shale were reported by Lee et al. inNature.1 The abstract started by quoting Darwin and affirming evolution, but then revealed evidence that complex eyes go further back in the fossil record than previously thought possible:
Despite the status of the eye as an “organ of extreme perfection”,theory suggests that complex eyes can evolve very rapidly. Thefossil record has, until now, been inadequate in providing insight into the early evolution of eyes during the initial radiation of many animal groups known as the Cambrian explosion. This is surprising because Cambrian Burgess-Shale-type deposits are replete with exquisitely preserved animals, especially arthropods, that possess eyes.However, with the exception of biomineralized trilobite eyes, virtuallynothing is known about the details of their optical design. Here wereport exceptionally preserved fossil eyes from the Early Cambrian(~515 million years ago) Emu Bay Shale of South Australia, revealing that some of the earliest arthropods possessed highly advanced compound eyes, each with over 3,000 large ommatidial lenses and a specialized ‘bright zone’. These are the oldest non-biomineralized eyes known in such detail, with preservation quality exceeding that found in the Burgess Shale and Chengjiang deposits. Non-biomineralized eyes of similar complexity are otherwise unknown until about 85 million years later. The arrangement and size of the lensesindicate that these eyes belonged to an active predator that was capable of seeing in low light. The eyes are more complex than those known from contemporaneous trilobites and are as advanced as those of many living forms. They provide further evidence that the Cambrian explosion involved rapid innovation in fine-scale anatomy as well as gross morphology, and are consistent with the concept that the development of advanced vision helped to drivethis great evolutionary event….
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