The trilobite, a creature that thrived in the seas for millions of years, was one of many animals wiped out in a mass extinction 252 million years ago that has been blamed on a microbe that spewed huge amounts of methane into Earth's atmosphere.   REUTERS
{"Image ImageDescription": "A fossil of a trilobite, a horsecrab-like creature that thrived in the seas for hundreds of millions of years before becoming one of many kinds of animals wiped out in a mass extinction that befell the planet 252 million years ago, is shown in this handout photo provided by the University of Chicago March 31, 2014.  A microbe that spewed humongous amounts of methane into Earth's atmosphere triggered a global catastrophe 252 million years ago that wiped out upwards of 90 percent of marine species and 70 percent of land vertebrates. That's the hypothesis offered on Monday by researchers aiming to solve one of science's enduring mysteries: what happened at the end of the Permian period to cause the worst of the five mass extinctions in Earth's history. REUTERS/Dan Dry/University of Chicago/Handout via Reuters  (UNITED STATES - Tags: SCIENCE TECHNOLOGY ENVIRONMENT ANIMALS) ATTENTION EDITORS - THIS PICTURE WAS PROVIDED BY A THIRD PARTY. REUTERS IS UNABLE TO INDEPENDENTLY VERIFY THE AUTHENTICITY, CONTENT, LOCATION OR DATE OF THIS IMAGE. THIS PICTURE IS DISTRIBUTED EXACTLY AS RECEIVED BY REUTERS, AS A SERVICE TO CLIENTS.  NO SALES. NO ARCHIVES. FOR EDITORIAL USE ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS", "Image Orientation": "Horizontal (normal)", "Image XResolution": "300", "Image YResolution": "300", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "Adobe Photoshop CS4 Macintosh", "Image DateTime": "2014:04:01 15:33:36", "Image Artist": "HANDOUT", "Image ExifOffset": "1428", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "1566", "Thumbnail JPEGInterchangeFormatLength": "0", "EXIF ColorSpace": "Uncalibrated", "EXIF ExifImageWidth": "2316", "EXIF ExifImageLength": "1538"}