Belemnite

Belemnites is an extinct group of coleoid cephalopods with the internal shell composed by rostrum, phragmocone and pro-ostracum. The oldest belemnits are known from the Late Triassic (210 Ma) and the last ones became extinct at the K/T boundary (66 Ma). The initial chamber (protoconch) is relatively large and sphaerical. The phragmocone is divided by septa into dense chambers and it is protected by the rostrum. Tiny fins were attached to the rostrum. Belemnites possessed ten arms with hooks, modern jaws and well developed ink-sac. The largest animals exceeded length of 2,5 meters (including arms)



## Keywords
Mesozoic, Triassic-Cretaceous, coleoid cephalopods, order Belemnitida