Psiloceras pacificum

Psiloceras pacificum
Specimen Number: NMMNH P-51297
Image By: Mary Sundstrom
Date: Spring 2008

Ammonites nearly went extinct at the end of the Triassic. Only one genus survived into the Jurassic, giving rise to the
diversity of ammonites that swam the Jurassic and Cretaceous seas. Triassic ammonites were diverse and most had complex shell shapes and ornamentation, unlike the smooth-shelled ammonite (Psiloceras) that survived the extinction.