Named By: Dal Sasso and Pinna - 1996.
Classification: Chordata, Reptilia, Ichthyopterygia, Ichthyosauria, Shastasauridae.
Species: B. leptorhynchus (type).
Size: Around 6 meters long.
Known locations: Italy.
Time period: Ladinian of the Triassic.
Fossil representation: Almost complete specimen that includes the remains of four embryos inside the body.
was a primitive icthyosaur
that lacked a dorsal fin and had a more
eel-like tail rather than the fish-like tail seen in later more
advanced genera. The jaws were long and thin, filled with small
conical teeth for trapping marine organisms. The eyes that were
around twenty centimetres in diameter may have been a deep water
adaptation for seeing and hunting in the black of deep water. In
fact, other shastasaurid ichthyosaurs are all envisioned as being
relatively slow (at least when compared to more advanced
ichthyosaurs) hunters of deep water cephalopods that descend to the
gloom to hide from other predators that can only see well in light
conditions. The presence of four unborn embryos inside the type
specimen of Besanosaurus not only indicates it was
a female, but that
at least some genera of ichthyosaurs were capable of giving birth to a
At six meters in length you might think that Besanosaurus was big, but in reality this was less than a third of the length of its giant relative Shastasaurus.
- Besanosaurus leptorhynchus n. gen. n. sp., a new shastasaurid ichthyosaur from the Middle Triassic of Besano (Lombardy, N. Italy). - Paleontologia Lombarda, Nuova serie, v. 4, p. 1-23. - C. Dal Sasso & G. Pinna - 1996.