Boesse Posted February 22, 2009 Share Posted February 22, 2009 Hey all, During a marine croc excavation I was on this last fall, we dug up a huge hybodont dorsal fin spine that measures about 36cm long. I'm relatively ignorant when it comes to pre-Miocene sharks, so I wanted to ask if this was abnormally large or not. Bobby Link to comment Share on other sites More sharing options...
non-remanié Posted February 22, 2009 Share Posted February 22, 2009 I think that would qualify as gigantic! I haven't seen reference to anything much larger than half that size in the upper cretaceous. What was the age of the deposits? Hey all,During a marine croc excavation I was on this last fall, we dug up a huge hybodont dorsal fin spine that measures about 36cm long. I'm relatively ignorant when it comes to pre-Miocene sharks, so I wanted to ask if this was abnormally large or not. Bobby ---Wie Wasser schleift den Stein, wir steigen und fallen--- Link to comment Share on other sites More sharing options...
Boesse Posted February 22, 2009 Author Share Posted February 22, 2009 I think that would qualify as gigantic! I haven't seen reference to anything much larger than half that size in the upper cretaceous. What was the age of the deposits? Aptian/Albian I believe. It's from the Thermopolis Formation. Link to comment Share on other sites More sharing options...
hybodus Posted February 22, 2009 Share Posted February 22, 2009 Aptian/Albian I believe. It's from the Thermopolis Formation. How about an image? Link to comment Share on other sites More sharing options...
PaleoRon Posted February 22, 2009 Share Posted February 22, 2009 I think the biggest spine I have seen was about 20 cm. It was from Morocco but it was complete and unrepaired. I thought that one was huge. Link to comment Share on other sites More sharing options...
Boesse Posted February 22, 2009 Author Share Posted February 22, 2009 I'll get a photo on here sometime later tonight or tommorrow. Trust me - this thing is BIG. Bobby Link to comment Share on other sites More sharing options...
RJB Posted February 22, 2009 Share Posted February 22, 2009 May I ask why people are finding these 'shark' spines? I know sharks teeth are found by the kajillion, but that the bones are cartilage and rarely fossilized. Why so many spines? I also saw several while in Tucson too. RB Link to comment Share on other sites More sharing options...
tracer Posted February 22, 2009 Share Posted February 22, 2009 i'm thinkin' they got kinda big... spine spine2 spine3 Link to comment Share on other sites More sharing options...
Harry Pristis Posted February 22, 2009 Share Posted February 22, 2009 May I ask why people are finding these 'shark' spines? I know sharks teeth are found by the kajillion, but that the bones are cartilage and rarely fossilized. Why so many spines? I also saw several while in Tucson too. RB Actually, I believe that fish spines -- e.g. hybodont and heterodont shark spines and catfish pectoral spines -- are derived not from the cartilaginous or boney skeleton, but from toothy origins. That is, they are made of dentin/enameloid. Amazing, huh! Here's one of the spines from Morocco: 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...
Auspex Posted February 22, 2009 Share Posted February 22, 2009 May I ask why people are finding these 'shark' spines? I know sharks teeth are found by the kajillion, but that the bones are cartilage and rarely fossilized. Why so many spines? I also saw several while in Tucson too. RB Hybodus was a Mesozoic shark (though it arose late in the Permian). Megs etc. didn't have spines. Wikipedia: http://en.wikipedia.org/wiki/Hybodus "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...
RJB Posted February 22, 2009 Share Posted February 22, 2009 Actually, I believe that fish spines -- e.g. hybodont and heterodont shark spines and catfish pectoral spines -- are derived not from the cartilaginous or boney skeleton, but from toothy origins. That is, they are made of dentin/enameloid. Amazing, huh!Here's one of the spines from Morocco: Jesus! That is amazing! Certainly explains why they are found. Not for dumb question #2, just where are these spines located on a shark? I prep lots of fishes and know where the spines can generaly be found, but a shark is totaly different. RB Link to comment Share on other sites More sharing options...
Harry Pristis Posted February 22, 2009 Share Posted February 22, 2009 Jesus! That is amazing! Certainly explains why they are found. Not for dumb question #2, just where are these spines located on a shark? I prep lots of fishes and know where the spines can generaly be found, but a shark is totaly different.RB In hybodonts, such spines were mounted at the leading edges of the dorsal and pectoral fins. I don't know if they had an erectile function, but it wouldn't surprise me if they did. Sorta' like catfish. 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...
Bill Posted February 22, 2009 Share Posted February 22, 2009 KOF, Bill. Welcome to the forum, all new members www.ukfossils check it out. Link to comment Share on other sites More sharing options...
RJB Posted February 22, 2009 Share Posted February 22, 2009 Jesus! I should have guessed, but I didnt have a clue. thanks a ton bill. Now I know. You guys are much smarter than little ole me thats for sure. RB Link to comment Share on other sites More sharing options...
Boesse Posted February 23, 2009 Author Share Posted February 23, 2009 I should mention that in conjunction with Harry's note is that this thing has little enameloid denticles or hooks on the trailing edge of the spine. Also, Ron, those ridges on the spines are made of enameloid (what sharks have instead of regular enamel; I don't actually know what's different). Bobby Link to comment Share on other sites More sharing options...
Auspex Posted February 23, 2009 Share Posted February 23, 2009 ...this thing has little enameloid denticles or hooks on the trailing edge of the spine. Like this: "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...
Harry Pristis Posted February 23, 2009 Share Posted February 23, 2009 I should mention that in conjunction with Harry's note is that this thing has little enameloid denticles or hooks on the trailing edge of the spine. Also, Ron, those ridges on the spines are made of enameloid (what sharks have instead of regular enamel; I don't actually know what's different).Bobby Genetically speaking, these spines in sharks are derived from enlarged dermal denticles in the same manner as stingray spines. I don't think catfish and other boney fish have dermal denticles, so I'm guessing that their pectoral spines are modified teeth that migrated out of the mouth. 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...
Boesse Posted February 23, 2009 Author Share Posted February 23, 2009 OK everyone, here it is, the moment you've all been waiting for. Check this thing out! And like I said, its about 36 cm, which is somewhere around 13 or 14". Bobby Link to comment Share on other sites More sharing options...
Bill Posted February 23, 2009 Share Posted February 23, 2009 These small bits from the Cretaceous Weald Clay, Surrey, England, show the barbs better. KOF, Bill. Welcome to the forum, all new members www.ukfossils check it out. Link to comment Share on other sites More sharing options...
Northern Sharks Posted February 23, 2009 Share Posted February 23, 2009 That is enormous!!!! Like Ron, the biggest one I had seen previously was between 8-9 inches from Morocco. Thanks for the pics There's no limit to what you can accomplish when you're supposed to be doing something else Link to comment Share on other sites More sharing options...
Boesse Posted February 23, 2009 Author Share Posted February 23, 2009 ...so does anybody know what the largest published spine is? Bobby Link to comment Share on other sites More sharing options...
AndyW Posted February 23, 2009 Share Posted February 23, 2009 big. this is a 35cm hybodus spine found in the uk, from astercanthus ornatissimus Link to comment Share on other sites More sharing options...
PaleoRon Posted February 23, 2009 Share Posted February 23, 2009 May I ask why people are finding these 'shark' spines? I know sharks teeth are found by the kajillion, but that the bones are cartilage and rarely fossilized. Why so many spines? I also saw several while in Tucson too. RB Shark spines seem to be derived from highly modified scales, which are also covered with an enameloid just like the teeth. One line of thought is that shark teeth originated as scales that migrated into the mouth and eventually became teeth. The spines are not present in all sharks but are restricted to more "primative" types of sharks. One type of shark that is still around that has spines is the Port Jackson shark, Heterodontus portusjacksoni. You may have seen it on a nature program getting spit out by a larger shark or fish that didn't like getting jabbed in the roof of their mouth with a sharp object. That spine seems to work like a charm. Fish fin spines are derived from the skeleton of bony fish, they are modified from the fin skeleton, just much more robust than a "regular" fin bone. Link to comment Share on other sites More sharing options...
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