RickNC Posted July 31, 2015 Share Posted July 31, 2015 Found the following specimens in an Eastern NC river in what is primarily a Cretaceous deposit with a bit of Eocene present. I'm wondering if they're shark coprolites. Link to comment Share on other sites More sharing options...
Harry Pristis Posted July 31, 2015 Share Posted July 31, 2015 I think they are coprolites, the ones with the spiral grooves, anyway. Search the TFF Gallery for comparison images. http://pristis.wix.com/the-demijohn-page What seest thou else In the dark backward and abysm of time? ---Shakespeare, The Tempest Link to comment Share on other sites More sharing options...
GeschWhat Posted August 1, 2015 Share Posted August 1, 2015 The darker one in the first and second photo looks a little dubious to me, but I think the other two are spiral coprolites. While spiral coprolites are often attributed to sharks, other fish such as rays, skates, gars, coelacanths, and lungfish are also known to have spiral valves. Nice find! Lori www.areallycrappystory.com/fossils www.facebook.com/fossilpoo Link to comment Share on other sites More sharing options...
jcbshark Posted August 1, 2015 Share Posted August 1, 2015 Nice finds Rick, coprolites are something I'm sure I've run across but have failed to recognize Every once in a great while it's not just a big rock down there! Link to comment Share on other sites More sharing options...
Harry Pristis Posted August 1, 2015 Share Posted August 1, 2015 The darker one in the first and second photo looks a little dubious to me, but I think the other two are spiral coprolites. While spiral coprolites are often attributed to sharks, other fish such as rays, skates, gars, coelacanths, and lungfish are also known to have spiral valves. Nice find! Sharks have two types of cloacal valves: scroll valve or spiral valve. Such valves increase the contact between the shark gut and food items, thus improving efficiency of nutrient uptake. Scroll valves are found in advanced sharks such as carchariniforms, while spiral valves are found in more primitive groups like lamniforms. A scroll valve produces a tightly-rolled "crepe" form of dropping (NPI). A spiral valve produces a corkscrew form of fecal pellet. http://pristis.wix.com/the-demijohn-page What seest thou else In the dark backward and abysm of time? ---Shakespeare, The Tempest Link to comment Share on other sites More sharing options...
fossilized6s Posted August 1, 2015 Share Posted August 1, 2015 Given their size, it would be neat to saw these in half and look for inclusions. Beauties. ~Charlie~ "There are those that look at things the way they are, and ask why.....i dream of things that never were, and ask why not?" ~RFK ->Get your Mosasaur print ->How to spot a fake Trilobite ->How to identify a CONCRETION from a DINOSAUR EGG Link to comment Share on other sites More sharing options...
RickNC Posted August 1, 2015 Author Share Posted August 1, 2015 Given their size, it would be neat to saw these in half and look for inclusions. Beauties. Unfortunately the reddish colored one in the first picture broke in half upon drying. I don't see anything obvious in there with my naked eye. Link to comment Share on other sites More sharing options...
GeschWhat Posted August 4, 2015 Share Posted August 4, 2015 (edited) Sharks have two types of cloacal valves: scroll valve or spiral valve. Such valves increase the contact between the shark gut and food items, thus improving efficiency of nutrient uptake. Scroll valves are found in advanced sharks such as carchariniforms, while spiral valves are found in more primitive groups like lamniforms. A scroll valve produces a tightly-rolled "crepe" form of dropping (NPI). A spiral valve produces a corkscrew form of fecal pellet. It is my understanding that a scroll valve is a type of spiral valve and none of these appear to be the product of a scroll type spiral valve. Just saying... Edited August 4, 2015 by GeschWhat Lori www.areallycrappystory.com/fossils www.facebook.com/fossilpoo Link to comment Share on other sites More sharing options...
Harry Pristis Posted August 4, 2015 Share Posted August 4, 2015 It is my understanding that a scroll valve is a type of spiral valve and none of these appear to be the product of a scroll type spiral valve. Just saying... My information is from Bretton W. Kent's book, FOSSIL SHARKS OF THE CHESAPEAKE BAY REGION, pp. 11. Where did you get your understanding, Gesch? http://pristis.wix.com/the-demijohn-page What seest thou else In the dark backward and abysm of time? ---Shakespeare, The Tempest Link to comment Share on other sites More sharing options...
Plax Posted August 4, 2015 Share Posted August 4, 2015 these look like worn coprolites to me, you can see fossils from a similar type of deposition on the black creek page of elasmo.com, don't think they show coprolites though Link to comment Share on other sites More sharing options...
GeschWhat Posted August 6, 2015 Share Posted August 6, 2015 My information is from Bretton W. Kent's book, FOSSIL SHARKS OF THE CHESAPEAKE BAY REGION, pp. 11. Where did you get your understanding, Gesch? Sorry if I touched a nerve, but I meant no offense. I have read numerous papers on the subject, and don't remember every reference. Doing a quick google search, Wikepedia and fishbase.org support my response. Again, sorry...I didn't mean to ruffle feathers. Lori www.areallycrappystory.com/fossils www.facebook.com/fossilpoo Link to comment Share on other sites More sharing options...
Harry Pristis Posted August 6, 2015 Share Posted August 6, 2015 (edited) No offense taken, Gesch. This is a search for knowledge and the terms we use to correctly transmit that knowledge. Both of your sources are generalized definitions. Try to find the next finer level of definition, the level that distinguishes between scroll and spiral valves. Here's one: from "Biology of [extant] Sharks & Rays" on-line course: There are three basic types of intestinal valve in sharks, termed spiral, scroll, and ring. The spiral valve is the 'classic' shark intestinal partition, resembling an auger in shape, and is found in cow sharks (family Hexanchidae), spiny dogfishes (Squalidae), and catsharks (Scyliorhinidae). The scroll valve resembles a loose roll of paper in shape, and is found in whaler sharks (Carcharhinidae, such as the Lemon Shark used in Wetherbee's gut-clearance experiment). The ring valve, resembling a series of tightly-packed lamellae (plates), is found in all extant lamnoids – including the White Shark. The ring valve offers the most absorptive surface area per unit length, and is thus highly efficient. http://www.elasmo-research.org/education/white_shark/digestion.htm This definition deals with extant sharks, of course. Fossil shark morphology in this area is mostly (if not entirely) known by extrapolation. A shark coprolite produced through a ring valve would be indistinguishable from any teleost coprolite, as far as I know. It may also be that ring valve droppings are not well-enough formed to survive as fossils. I guess that's why identifiable shark coprolites are described as scroll or spiral. Edited August 6, 2015 by Harry Pristis http://pristis.wix.com/the-demijohn-page What seest thou else In the dark backward and abysm of time? ---Shakespeare, The Tempest Link to comment Share on other sites More sharing options...
Plax Posted August 6, 2015 Share Posted August 6, 2015 keep in mind that these are from a multiply reworked lag also. It has been considered as having both Bladen and Peedee fossils reworked in to a basal Castle Hayne sequence. Pics 3,4 and 5 could possibly wear down to look like 1 and 2. Link to comment Share on other sites More sharing options...
Harry Pristis Posted August 6, 2015 Share Posted August 6, 2015 Good point, Plax. http://pristis.wix.com/the-demijohn-page What seest thou else In the dark backward and abysm of time? ---Shakespeare, The Tempest Link to comment Share on other sites More sharing options...
GeschWhat Posted August 7, 2015 Share Posted August 7, 2015 Lori www.areallycrappystory.com/fossils www.facebook.com/fossilpoo Link to comment Share on other sites More sharing options...
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