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Ptychodus-2010
Rare Protocallianassa mortoni Crab Claw - Cretaceous
A new hybodontiform shark (Strophodus Agassiz 1838) from the Lower Cretaceous (Valanginian-Hauterivian) of Colombia [PeerJ]
The Ptychodontid Sharks
What (giant) sharks actually existed in the Age of Dinosaurs? - Quora
Ptychodus Crusher Shark Tooth #1
Ptychodus - Wikipedia
The Ptychodontid Sharks
Ptychodus mortoni
Huge, 1.4 Fossil Crusher Shark (Ptychodus) Tooth - Kansas (#152255) For Sale
Worldwide shark teeth for sale
A revision of the Upper Cretaceous shark Ptychodus mediterraneus Canavari, 1916 from northeastern Italy, with a reassessment of P. latissimus and P. polygyrus Agassiz, 1835 (Chondrichthyes; Elasmobranchii) - ScienceDirect
Which type of shark is the best example of what prehistoric sharks looked like? - Quora
Shark Teeth - General Fossil Discussion - The Fossil Forum
Largest Ptychodus mortoni tooth for sale