Besanosaurus skull and flippers reconstructed

Figure 1. Besanosaurus in situ (below) and skull reconstructed (above).

Figure 1. Besanosaurus in situ (below) and skull reconstructed (above). Left flippers are reconstructed here from scattered phalanges.

Besanosaurus leptoryhnchus (Dal Sasso and Pinna 1996, Fig. 1) was a large Middle Triassic ichthyosaur with a small skull and slender flippers. The authors nested Besanosaurus between Shonisaurus + Himalayasaurus and Shastasaurinae (Merriamia, Pessosaurus, Californosaurus, Shastasaurus). Unfortunately none of those genera are presently included in the large reptile tree.  Besanosaurus nests here (Fig. 2) between Chaohusaurus and Qianichthyosaurus, two taxa not included in Dal Sasso and Pinna. Perhaps over the upcoming weekend more ichthyosaurs can be added to the large reptile tree. We nested Mikadocephalus at the base of the ichthyosaurs recently here.

Figure 2. Family tree of basal ichthyosaurs. Several taxa (listed above) are not yet included.

Figure 2. Family tree of basal ichthyosaurs. Several taxa (listed above) are not yet included.

Below are a series of ichthyosaur skulls to show how Besanosaurus nests with them. Gray bones below Besanosaurus may be hyoids.

Figure 3. How Besanosaurus nests among the ichthyosaurs listed.

Figure 3. How Besanosaurus nests among the ichthyosaurs listed.

The original identification of the skull bones is shown below (Fig. 4). A few changes were made here (Fig. 1).

Figure 4. Original identification of bones in Besanosaurus.

Figure 4. Original identification of bones in Besanosaurus by Dal Sasso and Pinna 1996.

References
Dal Sasso C and Pinna G 1996. Besanosaurus leptorhynchus n. gen. n. sp., a new shastasaurid ichthyosaur from the Middle Triassic of Besano (Lombardy, N. Italy). Paleontologia Lombardia 4:23 pp.

 

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s