holdinghistory Posted June 12, 2018 Share Posted June 12, 2018 I have a few trilobites from Nevada that are bugging me (pun intended). I just know that I have seen these before, but I can't remember or find what species they are. The first looks like some kind of Agnostid with spines off the pygidium. The second maybe a molted cephalon? Any idea of the species would be great! Link to comment Share on other sites More sharing options...
FossilDAWG Posted June 12, 2018 Share Posted June 12, 2018 The cephalon reminds me of Pterocephalia (see here for an image). The first image is a pygidium, but not of an agnostid as you can see it is segmented. Any idea of the source formation or age? Don Link to comment Share on other sites More sharing options...
holdinghistory Posted June 12, 2018 Author Share Posted June 12, 2018 I think it is Pioche or Chisolm shale. Thanks! Link to comment Share on other sites More sharing options...
Fossildude19 Posted June 12, 2018 Share Posted June 12, 2018 The pygidium looks like it may be from Zacanthoides nsp. 4 Tim - VETERAN SHALE SPLITTER VFOTM --- APRIL - 2015 __________________________________________________ "In every walk with nature one receives far more than he seeks." John Muir ~ ~ ~ ~ ><))))( *> About Me Link to comment Share on other sites More sharing options...
piranha Posted June 12, 2018 Share Posted June 12, 2018 Zacanthoides typicalis Amecephalus piochensis 1 Link to comment Share on other sites More sharing options...
holdinghistory Posted June 12, 2018 Author Share Posted June 12, 2018 Thanks! I had been wondering about the Zacanthoides, but the lack of the long pygidium spine was throwing me. Appreciate the help! Link to comment Share on other sites More sharing options...
piranha Posted June 12, 2018 Share Posted June 12, 2018 28 minutes ago, holdinghistory said: Thanks! I had been wondering about the Zacanthoides, but the lack of the long pygidium spine was throwing me. Appreciate the help! Look again closely, the spine is a thoracic spine: "Thoracic segment 8 having large, long axial spine that extends well beyond terminal spines of pygidium" Robison, R.A., & Babcock, L.E. 2011 Systematics, paleobiology, and taphonomy of some exceptionally preserved trilobites from Cambrian Lagerstätten of Utah. The University of Kansas, Paleontological Contributions, 5:1-47 PDF LINK Link to comment Share on other sites More sharing options...
holdinghistory Posted June 12, 2018 Author Share Posted June 12, 2018 Gotcha, thanks! Makes a lot more sense now. Link to comment Share on other sites More sharing options...
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