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Phillipsia peroccidens (Old designation Phillipsia Tuberculata)

Arizona Chris

Found both in the Mooney Falls and Thunder Springs members of the Redwall Limestone on the Mogollon Rim far south of the Grand Canyon, this is the most common trilobite.  While I know of no one that has found a totally complete specimen, we have all the molted parts available for study.  This specimen, collected off Highway 260 East of Payson is in a reddish fossiliferous chert that is packed with fossils.  Typical of the Thunder Springs member here.

From the album:

Mississippian Redwall Limestone Fossils, Arizona

· 9 images
  • 9 images
  • 4 image comments

Photo Information

  • Focal Length 6.3 mm
  • Exposure Time 1/60
  • f Aperture f/3.1
  • ISO Speed 250

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Actually, I already posted the new info on this trilobite, but it seems to have mysteriously disappeared.  
Here it is again for anyone interested in the paper that reassigned P. tuberculata as: Phillipsia peroccidens 
Brezinski, D. K. (2017)
Trilobites from the Redwall Limestone (Mississippian) of Arizona.
Annals of Carnegie Museum, 84(2):165-171

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DPS Ammonite


All dozen or so pieces of this trilobite that I found in the Redwall Limestone have been tails. I wonder if you, Chris, have also found mostly tails. @Arizona Chris Are the tails more likely to be preserved because of their structure, thicker shell etc? Please post pictures of the middle and head pieces.



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Arizona Chris


John, I think all the pieces are actually there too in the same layers, however because they are much smaller than an intact pygidium, you miss them.  One large boulder we found up near young that is still there somewhere had half a dozen pygidiums and maybe 3 glabellas, and a few free cheeks.  A complete crandidium eludes us!


Arizona Chris

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