Did The Ammonites Survive The K-Pg?
New Specimens!
Paleontology enthusiasts or not, we have all heard of the beloved K-Pg, most commonly known as the event that "killed off the dinosaurs". Most of the fans of this blog, if there are any left after this 6 month gap, are probably familiar with the fact that birds are indeed dinosaurs, so theoretically dinosaurs (or a lineage of them at the very least) did survive the K-Pg. Except the dinosaurs, however, there's many other creatures that inhabited the then hostile late cretaceous world in it's last days, including the very abundant ammonites. Like their ancestors and close relatives nautiluses, ammonites were all over the place during the mesozoic, and studies say they were in their prime during the cretaceous. However, unlike nautiluses, they didn't make it through the K-Pg... Or so we thought.
Obviously, this blog is not for conspiracy theories. We're not going be using similar arguments such as the megalodon theorists,but well rather attempt to see what could have caused the ammonites to go extinct, how did the nautiluses survive that and if there are any post-K-pg extinction fossils.
Ammonite Remains after the Cretaceous-Paleogene Mass Extinction Event (66 Mya)
(1) A Fossilized Hoploscaphites, one of the (according to Wikipedia) few ammonites to have possibly survived the K-Pg.I did some research and, to say the least, I didn't find little. Based on a study conducted by Marcin Machaiski and Claud Heinberg, various fossil ammonites have been found in sediments from the Danian era of the Paleocene, suggesting that ammonites did survive for a while after the tragic crisis. A Wikipedia article also states that the latest ammonite fossils are only 500,000 years after the K-Pg event, suggesting that the creatures were probably lucky.
(2) A specimen of Hoploscaphites from the Cerithium Limestone in Denmark .The Major surviving groups of ammonites are the scaphites, like the one shown above, and the baculites, which are similar to orthocones.
What Drove the Ammonites to Extinction?
It seems we'll be killing two birds with one stone with this question, as this also shows to us why did the nautiluses make it.
After research, I found out something even I, a Total ammonite lover didn't know, and that regards their diet: they fed on plankton, exclusively. Unlike other cephalopods which made it through the tragedy alive, ammonites were completely and gradually wiped out by the decrease of plankton as a result of the chicxulub impact. On the other hand, nautiloids stopped feeding on plankton a while after the ammonoid lineage evolved, helping them survive.
In the end, the Ammonoidea's diminish might not have been so horrible, since it opened way for larger, more adapted plankton feeding organisms to take way. See you in less than a month, hopefully!
And Now an apology...
No apologies are saving me. I know, it's been half a year since I've posted and I'd like to justify myself with writer's block. Along with some pressure in school, I've also gotten some new interests, however, now that my love for paleontology is coming back, I thought it would be appropriate to make a new post.
~
Sources!
Pictures:
1).
https://en.wikipedia.org/wiki/Paleocene_ammonites#/media/File:Hoploscaphites_ammonite.jpg
2).
https://www.researchgate.net/publication/261359356_Evidence_for_ammonite_survival_into_the_Danian_Paleogene_from_the_Cerithium_Limestone_at_Stevns_Klint_Denmark
3).
https://journals.pan.pl/Content/107497/PDF/264.pdf
Sources of Info:
Paleocene Ammonites: https://en.wikipedia.org/wiki/Paleocene_ammonites#/media/File:Hoploscaphites_ammonite.jpg
Evidence of Ammonite Survival Past the Danian: https://www.researchgate.net/publication/261359356_Evidence_for_ammonite_survival_into_the_Danian_Paleogene_from_the_Cerithium_Limestone_at_Stevns_Klint_Denmark
Dietary preferences:
https://www.newscientist.com/article/dn19924-ammonites-strict-diet-doomed-them-to-extinction/#:~:text=They%20ruled%20the%20seas%20for,have%20condemned%20them%20to%20extinction.
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