Hypothesis Discussion Thread

[elosha11]

Review in focus: theworldofanimals.proboards.com/thread/3649/large-bodied-sharks-outcompeted-pliosaurs

Cretoxyrhina mantelli appears to have been an incredibly formidable shark. There's lots of other evidence of its predation and/or feeding on mosasaurs or pliosaurs on the Oceans of Kansas website, which I and others have posted before.

Just so I'm clear, is your premise that these type of sharks may have outcompeted and contributed to the distinctions of various pliosaurus, but then in turn may have been out-competed by the mosasaurs that came later? It seems the Ginsu shark could easily hold its own with similar-sized or even somewhat longer mosasaurs, but at maximum size, they may have been unable to hold off the largest sized mosasaurs. Also, the idea is that mosasaurs reproduce much more rapidly than the sharks, which also contributed to displacing them.

[Life]

Mar 23, 2021 19:44:01 GMT 5 elosha11 said:

Cretoxyrhina mantelli appears to have been an incredibly formidable shark. There's lots of other evidence of its predation and/or feeding on mosasaurs or pliosaurs on the Oceans of Kansas website, which I and others have posted before.

Just so I'm clear, is your premise that these type of sharks may have outcompeted and contributed to the distinctions of various pliosaurus, but then in turn may have been out-competed by the mosasaurs that came later? It seems the Ginsu shark could easily hold its own with similar-sized or even somewhat longer mosasaurs, but at maximum size, they may have been unable to hold off the largest sized mosasaurs. Also, the idea is that mosasaurs reproduce much more rapidly than the sharks, which also contributed to displacing them.

Yes, radiation of large-bodied sharks seems to coincide with decline of Pliosaurs in the Albian; Pliosaurs are last noticed in the Turonian. This happened slowly but surely.

Dr. Mikael Siversson is the only paleontologist who noticed the obvious.

For reference: museum.wa.gov.au/explore/articles/marine-predators-cretaceous

Thread in WoA for reference: theworldofanimals.proboards.com/thread/34/rise-super-predatory-sharks

Holland (2018) provided much-needed evidence to build upon this theme and present a hypothesis. It was rather surprising to see Cretoxyrhinids taking their chances with one of the most formidable Pliosaurs to ever exist. My grin was just like that of Palpatine when I had the opportunity to check Holland (2018). Hahaha.

Cretoxyrhinids were formidable sharks no doubt.

The largely mysterious Campanian disruptions might have something to do with decline of Cretoxyrhinids (highlighted in the Profile); these disruptions nearly wiped out Mosasaurs but their reproductive capacity enabled them to bounce back. Cretoxyrhinids do not seem to be widespread after said disruptions - unable bounce back effectively perhaps? Said disruptions helped mitigate predation pressure(s) on living Mosasaurs and they had the luxury and capacity to grow bigger than ever before under favorable circumstances. So one can say that Mosasaurs outcompeted Cretoxyrhinids via circumstances. This entire dynamic warrants attention.

Ample information in this profile: theworldofanimals.proboards.com/thread/12/cretoxyrhina-mantelli

[Life]

I noticed additional information about genus Cretodus and updated my review. This shark could approach 11 m in TL. Holy...