Psittacosaurus fossil preserves uropatagia, convergent with Sharovipteryx

Here’s an observation
of convergence you won’t see anywhere else.

Figure 3. Sharovipteryx reconstructed. Note the flattened torso. ” data-image-caption=”

Figure 3. Sharovipteryx reconstructed. Note the flattened torso.

” data-medium-file=”https://pterosaurheresies.files.wordpress.com/2018/02/sharovipteryx-recon588.jpg?w=250″ data-large-file=”https://pterosaurheresies.files.wordpress.com/2018/02/sharovipteryx-recon588.jpg?w=584″ src=”https://pterosaurheresies.files.wordpress.com/2018/02/sharovipteryx-recon588.jpg” alt=”Figure 3. Sharovipteryx reconstructed. Note the flattened torso.” class=”wp-image-29678″ />

It’s well known that pterosaurs,
their ancestors and cousins, like Sharovipteryx (Fig 1) had uropatagia (= extradermal membranes behind each hind limb).

On the other hand,
It’s not so well known that a basal ceratopsian, Psittacosaurus (Fig 2, specimen SMF R 4970), also preserves a uropatagium trailing each hind limb.

Many artists and scientists say uropatagia enabled Sharovipteryx to glide,
but no one will ever imagine a gliding Psittacosaurus.

So… maybe uropatagia are not gliding membranes in non-pterosaurs.

Of what use are uropatagia in nonvolant tetrapods?
1) heat sink to cool the largest, most active muscles of the body;
2) extradermal areas for decoration;
3) shade/protection over egg clutches.
4) Anything else?

Psittacosaurus major
(Osborn 1923, You et al. 2008) is a sister to Yinlong with a larger rostrum and no premaxillary teeth in the LRT. Psittacosaurus is known from a wide variety of specimens with distinct skull shapes.

References
Mayr G, Peters SD, Plodowski G and Vogel O 2002. Bristle-like integumentary structures at the tail of the horned dinosaur Psittacosaurus. Naturwissenschaften. 89 (8): 361–365.
Osborn HF 1923. Two Lower Cretaceous dinosaurs from Mongolia. American Museum Novitates 95: 1–10.
You H−L, Tanou K and Dodson P 2008. New data on cranial anatomy of the ceratopsian dinosaur Psittacosaurus major. Acta Palaeontologica Polonica 53 (2): 183–196.

wiki/Psittacosaurus