Carl Posted March 25, 2015 Share Posted March 25, 2015 A posting for a friend. Presented is a cluster of ammonites (Menibites walnutensis, Young 1963) from an outcrop of the Merchantville Formation in southern New Jersey. It was collected by Ralph Johnson of Monmouth Amateur Paleontologists' Society and is half of a cluster of five individuals that may represent a mating accumulation. Enjoy! Link to comment Share on other sites More sharing options...
JustPlainPetrified Posted March 25, 2015 Share Posted March 25, 2015 Nice! Thanks for posting this Carl. Link to comment Share on other sites More sharing options...
non-remanié Posted March 25, 2015 Share Posted March 25, 2015 barely differentiable from the surrounding matrix. what skill, patience and perseverance must be necessary to collect specimens like this! btw the matrix is an unconsolidated glauconitic mud although its tough to tell from the picture ---Wie Wasser schleift den Stein, wir steigen und fallen--- Link to comment Share on other sites More sharing options...
Ludwigia Posted March 25, 2015 Share Posted March 25, 2015 Nice grouping! Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
Auspex Posted March 25, 2015 Share Posted March 25, 2015 What features/circumstances led them to the mating accumulation conclusion? "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...
Jeffrey P Posted March 25, 2015 Share Posted March 25, 2015 That's one incredible specimen from Mr. Johnson's collection of countless amazing specimens. New Jersey produces some of the world's best Cretaceous ammonites as proven by Ralph Johnson and his cohorts. Thanks Carl for posting this find. Link to comment Share on other sites More sharing options...
squali Posted March 26, 2015 Share Posted March 26, 2015 Great representation of merchantville preservation. What is the theory that differentiates this assemblage from a typical current accumulation? It's hard to remember why you drained the swamp when your surrounded by alligators. Link to comment Share on other sites More sharing options...
jpc Posted March 26, 2015 Share Posted March 26, 2015 We don't see too many NJ ammonites here. Thanks, Carl. Link to comment Share on other sites More sharing options...
Ludwigia Posted March 27, 2015 Share Posted March 27, 2015 What features/circumstances led them to the mating accumulation conclusion? I was assuming this is a tongue-in-the-cheek title...but let's hear what Carl has to say. Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
Carl Posted March 27, 2015 Author Share Posted March 27, 2015 Looks like my post disappeared! As I understand it this is part of a mass of several males around a female. Of course, this could be accidental, but who wants that interpretation? Link to comment Share on other sites More sharing options...
Auspex Posted March 27, 2015 Share Posted March 27, 2015 Looks like my post disappeared! As I understand it this is part of a mass of several males around a female. Of course, this could be accidental, but who wants that interpretation? "Lookin' for love"... Is there a modern analog for this behavior among the cephalopoda? "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...
piranha Posted March 27, 2015 Share Posted March 27, 2015 On 3/27/2015 at 8:41 AM, Auspex said: ...Is there a modern analog for this behavior among the cephalopoda? I think it's more likely a coincidental mass burial. Here is the modern Nautilus mating posture: Hayasaka, S., Kakinuma, Y., Saisho, T., Tabata, M., & Nagayama, T. (1983) Additional record of observation on Nautilus pompilius in the aquarium of Kamoike marine park, Kagoshima, Japan. Occasional Papers Kagoshima University Research Center for the South Pacific, 1:51-54 Link to comment Share on other sites More sharing options...
Carl Posted March 27, 2015 Author Share Posted March 27, 2015 I totally agree that it has high potential to be accidental. But as tempting as it is to use Nautilus mating to understand ammonite mating, I think it would almost certainly be unwise for a couple of reasons. First, modern nautiloids are no more than 2 genera being used to interpret an insanely diverse and geologically extensive group. Plus, the diversity of behaviors in modern cephalopods is mind-boggling to say the least. And finally, it seems ammonites are actually more closely related to octopuses than to nautiloids. There's basically no way I can think of to prove or disprove a mating know for these ammonites so we are left with a just-so story. Link to comment Share on other sites More sharing options...
non-remanié Posted March 27, 2015 Share Posted March 27, 2015 Are any cephalopod fossils actually found to be instantaneously preserved in marine sediments holding mating postures? I think what it more likely is that they all died in the same area during the mating season and thus many were buried together. I think that is really what is meant by "mating accumulation" in this case. Or am I wrong? I think it's more likely a coincidental mass burial. Here is the modern Nautilus mating posture: IMG1.jpg Hayasaka, S., Kakinuma, Y., Saisho, T., Tabata, M., & Nagayama, T. (1983) Additional record of observation on Nautilus pompilius in the aquarium of Kamoike marine park, Kagoshima, Japan. Occasional Papers Kagoshima University Research Center for the South Pacific, 1:51-54 ---Wie Wasser schleift den Stein, wir steigen und fallen--- Link to comment Share on other sites More sharing options...
Auspex Posted March 27, 2015 Share Posted March 27, 2015 Kipling could certainly have spun a good yarn about this! The idea is not impossible, but a conclusive interpretation will prove...illusive. 'Tis the reasoning process which is itself interesting! "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...
non-remanié Posted March 27, 2015 Share Posted March 27, 2015 Menabites walnutensis actually for anyone who may end up googling the name A posting for a friend. Presented is a cluster of ammonites (Menibites walnutensis, Young 1963) from an outcrop of the Merchantville Formation in southern New Jersey. It was collected by Ralph Johnson of Monmouth Amateur Paleontologists' Society and is half of a cluster of five individuals that may represent a mating accumulation. Enjoy! ---Wie Wasser schleift den Stein, wir steigen und fallen--- Link to comment Share on other sites More sharing options...
piranha Posted March 27, 2015 Share Posted March 27, 2015 Are any cephalopod fossils actually found to be instantaneously preserved in marine sediments holding mating postures? I think what it more likely is that they all died in the same area during the mating season and thus many were buried together. I think that is really what is meant by "mating accumulation" in this case. Or am I wrong? I wasn't questioning the definition of "mating accumulation", simply showing the actual mating posture of a modern Nautilus. I'm not aware of any statistical probabilities that could say anything with certainty about what they were doing at the the time of burial. It may well have been a mass feeding assemblage or some other plausible, yet common gregarious behavioral trait. Link to comment Share on other sites More sharing options...
non-remanié Posted March 27, 2015 Share Posted March 27, 2015 In general its a good issue to clear up, either way. I definitely didnt mean to imply that's exactly what you thought, but I know that some folks viewing this probably were/are thinking just that. And from your response, they could have been further confused by that issue. Thats all. And I agree that its quite a stretch to refer it to as a "mating accumulation", but I think it brings up these questions and does help everyone learn. I wasn't questioning the definition of "mating accumulation", simply showing the actual mating posture of a modern Nautilus. I'm not aware of any statistical probabilities that could say anything with certainty about what they were doing at the the time of burial. It may well have been a mass feeding assemblage or some other plausible, yet common gregarious behavioral trait. ---Wie Wasser schleift den Stein, wir steigen und fallen--- Link to comment Share on other sites More sharing options...
FossilDAWG Posted March 27, 2015 Share Posted March 27, 2015 Kipling could certainly have spun a good yarn about this! Puts a new spin on "my best beloved..." Don Link to comment Share on other sites More sharing options...
MikeR Posted March 27, 2015 Share Posted March 27, 2015 Dimorphism is well established with ammonites and the fact that you have several smaller shells (males?) around a larger shell (female?) might suggest that it is a mating cluster although no evidence exists to say it is. Also assuming that ammonite mortality is similar that of the modern nautilus the shells could float on the ocean surface quite awhile after death and wash into the shallows and deposited in mass after a storm. Mike "A problem solved is a problem caused"--Karl Pilkington "I was dead for millions of years before I was born and it never inconvenienced me a bit." -- Mark Twain Link to comment Share on other sites More sharing options...
TNGray Posted March 28, 2015 Share Posted March 28, 2015 Ammonites going and coming at the same time. Link to comment Share on other sites More sharing options...
andreas Posted March 29, 2015 Share Posted March 29, 2015 Beautyfull ammonites! Nice idea with the mating accumulation too. 6.. sells, but I do see only a normal current accumulation. All apertures of the ammonites point to the same direction like they do in current accumulations. Link to comment Share on other sites More sharing options...
mikeymig Posted March 29, 2015 Share Posted March 29, 2015 I agree with Mike R on this. Put a nautilus shell in a tub of water and it will float. Around the world and in many formations you can find mass assemblages of ammonites. A storm, red tide, or after mating (like some animals today) there is a mass die off and all the ammonites wash into the shallows/shore. I have a couple specimens that are of a micro and macro conch together with no other company. I like to refer to these as a mating pair but we all know that ammonites are long extinct and trying to infer life activities of an extinct creature is near impossible. Many times I've wondered how much there is to know. led zeppelin Link to comment Share on other sites More sharing options...
Ludwigia Posted March 30, 2015 Share Posted March 30, 2015 Besides, it's naturally unlogical that the female of the species dies off immediately after mating. The species that did that would be extinct before it arose Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
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