Fatally Bitten Ammonites – Discussion and References

Table of Contents

  1. Summary & Introduction
  2. Fatally Bitten Ammonites – Results and Interpretation
  3. Fatally Bitten Ammonites – Predatory Behavior
  4. Fatally Bitten Ammonites – Identity of the Predator
  5. Fatally Bitten Ammonites – Discussion and References


Roll (1935) argued that the ribs of perisphinctid ammonites protected them from this type of predation compared to the smooth shells of oppeliids and haploceratids. Ward (1981) documented increasing strength of sculpture in ammonoids and also interpreted it as a defensive reaction to predation. Using Ward’s categories of ribbing strength, the Liassic prey genera range across all Ward’s categories from category 1 (no sculpture to very fine ribbing, such as Cymbites) to category 4 (very strong ribbing as seen in Xipheroceras, Promicroceras, Arnioceras, Caenisites). It would seem the predator of the British Liassic ammonites selectively sought small individuals, rather than those with weak shells.


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