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Do you happen to know if belemnite stomach contents such as this have been studied? I wondered if there is any evidence to indicate what the belemnite may have been eating? I'd imagine it would consist of a diet of ostracods and crustacean parts. It would indeed be interesting if fragments of fish were found as this would imply an inherant high degree of manouverability and dexterity in the animal to catch them.
I think it is worth pointing out to anyone looking at the photos who is unfamiliar with belemnite anatomy is that the calcite rod, or rostrum, displayed is the counterweight at the rear of the body. The fact that it appears to have cracked and contents leaked out in picture #3 is misleading as the stomach was contained in the fleshy mantle and not within the rostrum itself. Interestingly, it appears to show that the stomach may have been placed to the rear of the body, perhaps just in front of the phragmocone. The rostrum is probably only a third to a quarter of the length of the complete animal.
I have read that ammonoids ate small floating crinoids, ostracods, and mostly small juvenile ammonoids, according to the few fossils with preserved stomach contents. The small ammonoid parts preserved in the stomach contents were aptychi or jaws, and crushed shell. Seems they would float around floating mats of seaweed, and pick off the small fry as they came into range. Ammonoids are not belemnites, though they possibly ate about the same things. The belemnites were probably much faster and could catch faster prey. I will try to remember where I read this and post a reference.
Monks and Palmer also discuss ammonoid prey, and suggest that belemnites, because they had hooks on their arms, fed more like modern squid, mostly on small fish and crustaceans.
found the references:
Nixon, Marion, Morphology of the Jaws and Radula:
Westermann, G.E.G., Ammonoid Life and Habitat:
in Landman, Neil H., Kazushige Tanabe, and Richard Arnold Davis, editors, 1996, Ammonoid paleobiology. Plenum Press, New York [ISBN: 0-306-45222-7]
Monks, Neil and Palmer, P., 2002, Ammonites. Smithsonian Institution Press [ISBN: 1588340244]