married2rick Posted November 3, 2015 Share Posted November 3, 2015 I found this fossil in Juniata County, Pa. I cannot find anything online that remotely resembles it. It is about 3" long and 3/4" wide. Link to comment Share on other sites More sharing options...
piranha Posted November 3, 2015 Share Posted November 3, 2015 Bactrites aciculum LINK 4 Link to comment Share on other sites More sharing options...
Auspex Posted November 3, 2015 Share Posted November 3, 2015 Domed chamber wall; cephalopod. Longitudinal 'groove'; Bactrites. Mahantango; B. aciculum. Good pull Scott! 1 "There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant “Try to learn something about everything and everything about something.” - Thomas Henry Huxley >Paleontology is an evolving science. >May your wonders never cease! Link to comment Share on other sites More sharing options...
married2rick Posted November 3, 2015 Author Share Posted November 3, 2015 (Remember I'm new at this so sorry if my questions are elementary) Is this a tentacle of the cephalopod? Here is a pic of the exposed end. Link to comment Share on other sites More sharing options...
married2rick Posted November 3, 2015 Author Share Posted November 3, 2015 Link to comment Share on other sites More sharing options...
Fossildude19 Posted November 3, 2015 Share Posted November 3, 2015 (edited) Pretty nice Bactrites! Are you referring to the yellowish area? That appears to be an encrusting bryozoan, called Reptaria stolonifera. If there were tentacles, that would be soft body preservation. That happens, but not in the Mahantango formation. Your fossil is the internal mold of the inner part of the cephalopod. The small dot at the rounded end would be the siphuncle - a tube that ran through all of the chambers of the nautiloid that regulated water flow in each chamber. Hope this helps. Regards, Edited November 3, 2015 by Fossildude19 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...
abyssunder Posted November 3, 2015 Share Posted November 3, 2015 I agree. Good IDs. The bryozoan is tiny but very nice. " We are not separate and independent entities, but like links in a chain, and we could not by any means be what we are without those who went before us and showed us the way. " Thomas Mann My Library Link to comment Share on other sites More sharing options...
married2rick Posted November 4, 2015 Author Share Posted November 4, 2015 Holy mackeral fossildude19! Your response was exactly what I needed to hear. I could understand it AND you included a pic, awesome! Thank you, Thank you! Link to comment Share on other sites More sharing options...
FossilDAWG Posted November 4, 2015 Share Posted November 4, 2015 I have to express some reservation about the ID as Bactrites. From Wikipedia (which corroborates my recollection): "Bactritida (Erben 1964) are characterized by orthoconic to cyrtochonic shells that may be long or short with a narrow siphuncle invariably in contact with the ventral wall and sutures uniformly with V-shaped ventral lobes." I've underlined the relevant part. I happen to recall this because this is the feature that suggests the Bactritida are ancestoral to the ammonoids, which also have the siphuncle in contact with the ventral wall. On the other hand, the end of the specimen in question seems to show the siphuncle in almost the center of the septum: Also the size (3 inches long, 3/4 inch wide) seems gigantic for a Bactrites to me. However, my experience with the genus is entirely small pyritized specimens from Arkona which might be misleading. Based on the position of the siphuncle I'd suggest a tentative ID with a Michelinoceras or some related genus. Don 4 Link to comment Share on other sites More sharing options...
married2rick Posted November 4, 2015 Author Share Posted November 4, 2015 I just remeasured. It is only 2" long by almost 3/4" wide. And the siphuncle is not perfectly centered from top to bottom, it's nearer to the top. (Assuming it's the top). It is somewhat centered from left to right. It isn't perfectly round either but more like a slightly flattened hose. I will research a Michelinoceras tonight. Thank you again, everyone, thank you! Link to comment Share on other sites More sharing options...
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