Named By: K. Weitzel - 1935.
Classification: Chordata, Reptilia, Crocodilia, Alligatoridae, Alligatorinae.
Species: H. haupti (type).
Known locations: Germany - Messel Pit.
Time period: Early Eocene.
Fossil representation: At least two specimens.
In 1941 an alligator specimen from the Green River Formation was interpreted as being a new species of Hassiacosuchus by C. C. Mook. However a later 1967 study by Wassersug and Hecht found the remains of the second species actually belonged within the Procaimanoidea genus, and as such the second species of Hassiacosuchus became the second species of Procaimanoidea. This also makes Hassiacosuchus a distinctly European genus, however its future as a distinct genus is in doubt. Later studies have suggested that Hassiacosuchus may in fact belong within another North American genus called Allognathosuchus, although in 2004 another study by Christopher Brochu has led to the recommendation that Hassiacosuchus remain a distinct genus.
- Hassiacosuchus haupti n. g. n. sp., ein durophages Krokodil aus dem Mitteleozän von Messel - Notizblatt des Vereins für Erdkunde und der Hessischen Geologischen Landesanstalt Darmstadt (in German) 16: 40–49. - K. Weitzel - 1935.
- The status of the crocodylid genera Procaimanoidea and Hassiacosuchus in the New World - Herpetologica 23 (1): 30–34. - R. J. Wassersug - 1967.