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Mashable: Brain part vanished in modern arthropods

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Compared to those of 500 mya


The new research focuses on an oval structure, called the anterior sclerite, found in the heads of ancient arthropods. The anterior sclerite has long baffled researchers, especially because some prehistoric arthropods have it while others don’t, and its location in the head changes, depending on the quality of the fossil.

But now, fossilized brains have helped solve that mystery. An analysis of the anterior sclerites in two arthropod fossils, both more than 500 million years old, indicates that the structures were associated with the creatures’ bulbous eyes. The findings provide evidence that these oval structures were associated with nerves originating in the anterior region of the brain, according to the study.

Living arthropods don’t have an anterior sclerite, which suggests the heads of arthropods have changed over time, experts said.

“This suggests that the anterior sclerite was lost or fused to the head shield in living arthropods,” said David Legg, a research fellow with expertise in early arthropod evolution and phylogenetics at the Oxford University Museum of Natural History in the United Kingdom, who was not involved with the study.

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as to:
500-Million-Year-Old Brains of 'Sea Monsters' Get Close Look - May 07, 2015 Excerpt: fossilized brains have helped solve that mystery. An analysis of the anterior sclerites in two arthropod fossils, both more than 500 million years old, indicates that the structures were associated with the creatures' bulbous eyes.,,, http://www.livescience.com/50770-fossilized-brains-arthropod-evolution.html
As to 'bulbous eyes': Eyes of ancient arthropods, particularly the trilobite, are fascinating in the integrated complexity (i.e. design) inherent within them:
Evolution vs. The Trilobite Eye - Andy McIntosh 36:29 minute mark - video https://www.youtube.com/watch?feature=player_detailpage&v=D9p-L4x2iyU#t=2189 The Trilobite Eye - many different examples - illustrations http://www.trilobites.info/eyes.htm
Here are a few quotes on the wondrous trilobite eye from Don Johnson's book 'Programming of Life':
The Optimal Trilobite Eye - per Dr. Don Johnson - Programming of Life page 68-66 and appendix F: Trilobites suddenly appeared in the Cambrian (lowest fossil-bearing) stratum with no record of ancestry. The trilobite eye is made of optically transparent calcium carbonate (calcite, the same mineral of its shell) with a precisely aligned optical axis that eliminates double images and two lenses affixed together to eliminate spherical aberrations [McC98, Gal00]. Paleontologist Niles Eldredge observed, “These lenses--technically termed aspherical, aplanatic lenses--optimize both light collecting and image formation better than any lens ever conceived. We can be justifiably amazed that these trilobites, very early in the history of life on earth, hit upon the best possible lens that optical physics has ever been able to formulate” [Eld76]. Notice these lenses weren’t just good as, but were better than anything modern optical physicists have been able to conceive! ,,, “The design of the trilobite’s eye lens could well qualify for a patent disclosure” [Lev93p58].,,, The trilobite lens is particularly intriguing since the only other animal to use inorganic focusing material is man. The lens may be classified as a prosthetic device since it was non-biological, which also means the lens itself, with apparently no DNA inherent within, was not subject to Darwinian evolution. The manufacturing and controlling of the lenses were obviously biological processes, with an unknown number DNA-prescribed proteins (each with a prescriptive manufacturing program) for collecting and processing the raw materials to manufacture the precision lenses and create the refracting interface between the two lenses. The lenses do not decompose as any other animal’s lenses would, so they are subject to rigorous scientific investigation,,, Since no immediate precursors of trilobites have been found, Darwinists are without any evidence as to how an organism with an eye as complex as a trilobite could have arisen,,, especially in,, the lowest multi-cellular fossil-bearing stratum,,, Appendix F: “Trilobites had solved a very elegant physical problem and apparently knew about Fermat’s principle, Abbe’s sine law, Snell’s laws of refraction and the optics of birefringent crystals” [Cla75] “the rigid trilobite doublet lens had remarkable depth of field (near and far focusing) and minimal spherical aberration” [Gon07] Physicist Riccardo Levi-Setti observes: “In fact, this doublet is a device so typically associated with human invention that its discovery comes as something of a shock. The realization that trilobites developed and used such devices half a billion years ago makes the shock even greater. And a final discovery - that the refracting interface between the two elements in a trilobite’s eyes was designed in accordance with optical constructions worked out by Descartes and Huygens in the mid-seventeenth century - borders on sheer science fiction” [Lev93p57]. “The trilobites already had a highly advanced visual system. In fact, so far as we can tell from the fossil record thus far discovered, trilobite sight was far and away the most advanced in Kingdom Animalia at the base of the Cambrian,,, There is no other known occurrence of calcite eyes in the fossil record” [FM-trib].
Moreover, now eyes that are even more complex than trilobite eyes have been discovered in the Cambrian period:
Complex Arthropod Eyes Found in Early Cambrian - June 2011 Excerpt: Complex eyes with modern optics from an unknown arthropod, more complex than trilobite eyes, have been discovered in early Cambrian strata from southern Australia.,,, Here we report 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 lenses indicate 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, http://crev.info/content/110629-complex_arthropod_eyes_found_in_early_cambrian Modern optics in the eyes of an Early Cambrian arthropod - June 2011 Excerpt: 'the Emu Bay Shale, which provides exquisite preservation of Early Cambrian animals, has now supplied us with the earliest example of an non-trilobite arthropod eye. Of the seven specimens recovered to date, three are spectacular for the detail revealed and stunning because they document eyes that "are as advanced as those of many living forms" http://www.arn.org/blogs/index.php/literature/2011/07/01/modern_optics_in_the_eyes_of_an_early_ca 500 million-year-old super predator had remarkable vision - Dec 07, 2011 Excerpt: 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, with each eye up to 3 cm in length and containing over 16,000 lenses. 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 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,,,, http://www.physorg.com/news/2011-12-million-year-old-super-predator-remarkable-vision.html Anomalocaris – Sea Monster – video http://www.youtube.com/watch?&v=ice47loNmsc
Of supplemental note:
Complex brains evolved much earlier than previously thought, 520-million-year-old fossilized arthropod confirms October 10, 2012 Excerpt: Complex brains evolved much earlier than previously thought, as evidenced by a 520-million year old fossilized arthropod with remarkably well-preserved brain structures.,,, "No one expected such an advanced brain would have evolved so early in the history of multicellular animals," said Strausfeld, a Regents Professor in the UA department of neuroscience.,,, "The shape [of the fossilized brain] matches that of a comparable sized modern malacostracan," the authors write in Nature. They argue the fossil supports the hypothesis that branchiopod brains evolved from a previously complex to a more simple architecture instead of the other way around.,,, "It is remarkable how constant the ground pattern of the nervous system has remained for probably more than 550 million years," Strausfeld added. "The basic organization of the computational circuitry that deals, say, with smelling, appears to be the same as the one that deals with vision, or mechanical sensation." http://phys.org/news/2012-10-complex-brains-evolved-earlier-previously.html Neural tissue preservation in a Cambrian arthropod - David Tyler - 11/05/13 Excerpt: However, the neural architecture is essentially modern.,,, "Professor Strausfeld said: 'Greg plugged these characteristics into a computer-based cladistic analysis to ask, "where does this fossil appear in a relational tree?" 'Our fossil of Alalcomenaeus came out with the modern chelicerates." "No one expected such an advanced brain would have evolved so early in the history of multicellular animals," said Strausfeld, a Regents Professor in the UA department of neuroscience. [. . .] "In principle, Fuxianhuia's is a very modern brain in an ancient animal." So we have the interesting situation that both groups of arthropods have neural patterns that are essentially modern.,,, The research considered in this blog shows that the neural pathways for arthropods must be dated at least to the Early Cambrian. This provides an additional dimension to the Cambrian Explosion phenomenon,,, http://www.arn.org/blogs/index.php/literature/2013/11/05/neural_tissue_preservation_in_a_cambrian

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