C. calcagnii is known from both the Cava superiore and Cava inferiore beds of the Lower Meride Limestone at Monte San Giorgio, dating to the latest Anisian of the Middle Triassic. Rieppel (1998) suggested that the back then monospecific genus Ceresiosaurus, is a junior synonym of the better known Lariosaurus, yet he kept it type species as a separate species under the new combination L. calcagnii.
C. calcagnii was found in both the Cava superiore and Cava inferiore beds of the Lower Meride Limestone at Monte San Giorgio, dating to the latest Anisian period of the Middle Triassic. Rieppel (1998) proposed that Ceresiosaurus is a junior synonym of Lariosaurus, but he kept it as a separate species under the new combination L. calcagnii.