page_title: Phacops rana
section_title: Description
hierarchical_section_title: Phacops rana / Description
caption_attribution_description: Mass of Phacops rana 365 million years old, Middle Devonian
context_page_description: Phacops rana is a species of trilobite from the middle Devonian period. Their fossils are found chiefly in the northeastern United States, southwestern Ontario, and in Morocco.
context_section_description: Phacops rana can be recognized by its large eyes (which remind some observers of a frog's eyes—the specific name rana is a reference to a common frog), its fairly large size (up to 6 inches long), and its habit of rolling up into a ball like a pill bug ("volvation"). In order to protect themselves from predators, Phacops rana would roll into a ball with its hard exoskeleton on the outside as protection. Many other trilobites possessed the same ability, but Phacops rana nearly perfected it. The slightest amount of sediment would trigger their senses, and Phacops rana would be hidden in a tiny shelter made of its own body. Although this safety feature often helped them to evade predators, occasionally it backfired and the trilobite would be buried under heavy sediment. Their fossils can still be found in balled-up positions 400 million years later.
caption: Phacops rana fossils
exif: {"Image Make": "Canon", "Image Model": "Canon PowerShot SD1000", "Image Orientation": "Horizontal (normal)", "Image XResolution": "180", "Image YResolution": "180", "Image ResolutionUnit": "Pixels/Inch", "Image DateTime": "2008:10:10 10:12:47", "Image YCbCrPositioning": "Centered", "Image ExifOffset": "196", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "180", "Thumbnail YResolution": "180", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "5108", "Thumbnail JPEGInterchangeFormatLength": "3798", "EXIF ExposureTime": "1/8", "EXIF FNumber": "14/5", "EXIF ISOSpeedRatings": "200", "EXIF ExifVersion": "0220", "EXIF DateTimeOriginal": "2008:10:10 10:12:47", "EXIF DateTimeDigitized": "2008:10:10 10:12:47", "EXIF ComponentsConfiguration": "YCbCr", "EXIF CompressedBitsPerPixel": "3", "EXIF ShutterSpeedValue": "3", "EXIF ApertureValue": "95/32", "EXIF ExposureBiasValue": "0", "EXIF MaxApertureValue": "95/32", "EXIF MeteringMode": "Pattern", "EXIF Flash": "Flash did not fire, compulsory flash mode", "EXIF FocalLength": "29/5", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "3072", "EXIF ExifImageLength": "2304", "Interoperability InteroperabilityIndex": "R98", "Interoperability InteroperabilityVersion": "[48, 49, 48, 48]", "Interoperability RelatedImageWidth": "3072", "Interoperability RelatedImageLength": "2304", "EXIF InteroperabilityOffset": "3334", "EXIF FocalPlaneXResolution": "40960/3", "EXIF FocalPlaneYResolution": "2304000/169", "EXIF FocalPlaneResolutionUnit": "2", "EXIF SensingMethod": "One-chip color area", "EXIF FileSource": "Digital Camera", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Auto", "EXIF DigitalZoomRatio": "1", "EXIF SceneCaptureType": "Standard"}