Phytosaurs might look like modern crocodiles, but they are different.  They fill the same ecological niches in ecosystems, however, the extinct phytosaurs only resemble modern crocodilians superficially.  The nostril position for example. In phytosaurs, due to the extended premaxillae the nostrils are located much closer to the eyes.  In addition, the layout of the manus and pedes is different.

The Phytosaur Pes

In phytosaurs, the fourth digit of the foot (IV) tends to be the largest. In contrast, digit V (the fifth digit) is much reduced, although it still possessed a claw. From what we can see, the new CollectA Colossosuchus phytosaur model has anatomically accurate hind feet. Overall, it seems quite an accurate representation of a mystriosuchine phytosaur,

The phytosaur pedes – a helpful guide. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

To view the range of CollectA figures in stock at Everything Dinosaur: CollectA Prehistoric Life Figures.

Remember, the singular is pes, when discussing both hind feet the plural is used – pedes.

The Phytosaur Manus

To the best of our knowledge the manus (hand) of phytosaurs has the following digit formula (right manus).

In a right manus (forelimb/hand) of a typical phytosaur:

• Digit I (pollex) is located on the medial side, nearest to the body’s midline.
• Digit V is the lateral-most digit, located farthest from the midline.

The implications for phytosaur models are significant. When reconstructing a right manus, if viewed from the dorsal (top) side, the correct digit arrangement (from medial to lateral) is:

I → II → III → IV → V

This means:

Digit I is the “thumb” side.

Digit V is the “little finger” side.

If the manus is oriented palm-down (pronated), the pollex (digit I) points toward the midline of the animal.  The CollectA Colossosuchus manus has five digits.  They all seem in proportion, although I am not sure whether the outermost digit (V) had a claw.  In the CollectA phytosaur model, digit V is much reduced, and it has a tiny claw.

Mike from Everything Dinosaur commented:

“Although bones from the pedes and manus are known in the Phytosauria fossil record, they are rare.  However, palaeontologists have been able to use trackways assigned to phytosaurs to work out the anatomy.”

The Everything Dinosaur website: Prehistoric Animal Models.