Peat Burns Posted May 6, 2017 Share Posted May 6, 2017 I am hoping someone out there is extremely familiar with the surface texture of late Ordovician trilobites of the Cincinnatian. I found this in St. Leon, Indiana. I believe it is a trilobite glabella, and there might be a little bit more to expose. Normally I wouldn't get excited about a trilobite fragment, but finding anything other than Isotelus or Flexicalymene at this site is a bit rare, and this could add a new taxon to my collection for that site. Taxa that I thought might be candidates include: * Ceraurus milleranus * Amphilichas shideleri * Tricopelta breviceps Thanks for any help. (scale is in mm) Link to comment Share on other sites More sharing options...
erose Posted May 6, 2017 Share Posted May 6, 2017 Try these web sites: http://strata.uga.edu/cincy/fauna/trilobita/trilobita.html and http://drydredgers.org/fragoth1.htm I also get excited finding trilo bits that are not the "usual suspects." Good find. PS There have been some beautiful and complete specimens found at that cut other than Isotelus and Flexicalymene so keep your eyes wide open. 3 Link to comment Share on other sites More sharing options...
piranha Posted May 6, 2017 Share Posted May 6, 2017 This is a partial Amphilichas cranidium. There is a portion of the glabella, composite lateral lobe (cl), longitudinal (lf) occipital (of) furrows and the occipital ring. 7 Link to comment Share on other sites More sharing options...
Peat Burns Posted May 6, 2017 Author Share Posted May 6, 2017 1 hour ago, erose said: Try these web sites: http://strata.uga.edu/cincy/fauna/trilobita/trilobita.html and http://drydredgers.org/fragoth1.htm I also get excited finding trilo bits that are not the "usual suspects." Good find. PS There have been some beautiful and complete specimens found at that cut other than Isotelus and Flexicalymene so keep your eyes wide open. Thank you, erose. I just can't get enough time on that cut. I'd like to just camp out there for a couple days... 4 hour trips here and there are just not enough to find the rare stuff that I know is hiding in there Link to comment Share on other sites More sharing options...
Peat Burns Posted May 6, 2017 Author Share Posted May 6, 2017 26 minutes ago, piranha said: This is a partial Amphilichas cranidium. There is a portion of the glabella, composite lateral lobe (cl), longitudinal (lf) occipital (of) furrows and the occipital ring. Thank you, piranha. I was hoping you'd be lurking. This is extremely helpful, as it gives me a better idea of the orientation. I doubt if there is much more there posteriorly, but I'm going to peel back some of the matrix and find out nonetheless. Thanks again. Link to comment Share on other sites More sharing options...
piranha Posted May 6, 2017 Share Posted May 6, 2017 Here is the original description of Amphilichas (=Acrolichas) shideleri Foerste, A.F. (1919) LINK Notes on Isotelus, Acrolichas, Calymene, and Encrinurus. Bulletin of the Scientific Laboratories of Denison University, 19:65-81 There is very little published info on this species. Dan Cooper did a brief description for MAPS 1986. Cooper, Dan (1986) Cincinnatian Trilobites. MAPS Digest, 9(4&5):24-32 Amphilichas shideleri Cranidium moderately convex; glabella broad and subrectangular; median lobe expanded anteriorly; basal area tending to become depressed; foremost pair of lateral glabellar furrows extended backward to form longitudinal furrows reaching occipital furrow; axial furrows diverted posteriorly; circumscribed occipital lobes present; occipital ring broad; preglabellar field absent; fixigenae subtriangular; palpebral lobes marked off by furrows; anterior sections of facial sutures converging forward, running parallel to axial furrows. Thorax composed of 11 segments; axis broad; axial furrows shallow; pleurae horizontal and transverse proximally, bent downward and backward at fulcra. Pygidium with axis extending whole of length and unfurrowed 3rd pleurae with single free points. One of the rarest of Cincinnatian trilobites, even fragments of this species are extremely rare to find. Only one complete specimen owned by the Smithsonian was known until Jeff Aubry, Bill White, Bob White, Steve Felton, David Cooper and myself made a co-sponsored dig producing 5 complete specimens. 4 of those specimens are now in the possession of the Cincinnati Museum of Natural History. 7 Link to comment Share on other sites More sharing options...
Peat Burns Posted May 6, 2017 Author Share Posted May 6, 2017 @piranha, this is very informative. Thank you. Do you have any ideas about why this species is so rare? Do you think it was rare throughout the palaeoenvironment, or is it more likely a function of taphonomy? Maybe a facies fossil? Link to comment Share on other sites More sharing options...
piranha Posted May 6, 2017 Share Posted May 6, 2017 Yes, wherever they are found, lichids are usually rare trilobites. Evidently, this one is exceedingly rare. Congrats! Link to comment Share on other sites More sharing options...
Peat Burns Posted May 6, 2017 Author Share Posted May 6, 2017 1 hour ago, piranha said: Yes, wherever they are found, lichids are usually rare trilobites. Evidently, this one is exceedingly rare. Congrats! Fascinating. Thanks again for all the info. I am very pleased with this find 1 Link to comment Share on other sites More sharing options...
fifbrindacier Posted May 6, 2017 Share Posted May 6, 2017 That's nice, i'm happy for you. 1 "On ne voit bien que par le coeur, l'essentiel est invisible pour les yeux." (Antoine de Saint-Exupéry) "We only well see with the heart, the essential is invisible for the eyes." In memory of Doren Link to comment Share on other sites More sharing options...
piranha Posted May 7, 2017 Share Posted May 7, 2017 1 hour ago, Peat Burns said: Fascinating. Thanks again for all the info. I am very pleased with this find Glad to assist! If you find any others for comparison, here are a couple of Smithsonian specimens. 3 Link to comment Share on other sites More sharing options...
Peat Burns Posted May 8, 2017 Author Share Posted May 8, 2017 I removed the matrix from what is present of the cranidium. Here is a "before", "after", and an overlay over the specimen photo that @piranha provided to show what is present and place it into context. Thanks again! 9 Link to comment Share on other sites More sharing options...
westcoast Posted May 8, 2017 Share Posted May 8, 2017 Beautiful informative illustrative work. 1 Link to comment Share on other sites More sharing options...
piranha Posted May 8, 2017 Share Posted May 8, 2017 On 5/7/2017 at 9:39 PM, Peat Burns said: I removed the matrix from what is present of the cranidium. Here is a "before", "after", and an overlay over the specimen photo that @piranha provided to show what is present and place it into context. Thanks again! On 5/7/2017 at 11:13 PM, westcoast said: Beautiful informative illustrative work. As predicted lol... Elementary, my Dear Watson! Link to comment Share on other sites More sharing options...
Malcolmt Posted May 8, 2017 Share Posted May 8, 2017 very very nice...... this bug is on my list of never having found a complete one, all I have are some bits and pieces 1 Link to comment Share on other sites More sharing options...
Fossil Claw Posted May 11, 2017 Share Posted May 11, 2017 Not sure if it's the same species as the person you found. But I was extremely lucky in January of 2016 to win a partial amphilichas that is I would guess is about 3/4 complete insanely cheap on eBay for Mount Orab. Paid like $7.25 delivered. Seller probably was not to happy with that acution result. 1 Link to comment Share on other sites More sharing options...
Peat Burns Posted May 11, 2017 Author Share Posted May 11, 2017 49 minutes ago, Fossil Claw said: Not sure if it's the same species as the person you found. But I was extremely lucky in January of 2016 to win a partial amphilichas that is I would guess is about 3/4 complete insanely cheap on eBay for Mount Orab. Paid like $7.25 delivered. Seller probably was not to happy with that acution result. Wow. That was a good deal. I think some people just like perfect, aesthetically pleasing fossils and don't want such partials. Maybe that's why it went so cheaply. The good news is that allows those of us who are students of palaeoecology and fossil assemblages to scarf them up! Congrats on the nice score. Link to comment Share on other sites More sharing options...
Fossil-Hound Posted May 13, 2017 Share Posted May 13, 2017 @Peat Burns congratulations on the rare trilobite fragment. Do or do not. There is no try. - Yoda Link to comment Share on other sites More sharing options...
Peat Burns Posted May 13, 2017 Author Share Posted May 13, 2017 5 hours ago, Fossil-Hound said: @Peat Burns congratulations on the rare trilobite fragment. Thanks! Link to comment Share on other sites More sharing options...
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