Preserved cloacal opening in Psittacosaurus

[Newt]

Open access here


This brief note describes the peculiar V-shaped, pigmented vent of the famous Frankfurt Psittacosaurus specimen that revealed the animal's integument structure and coloration.

[Halichoeres]

"Open access." [lascivious snickering]

That was my first thought. My second was, 'what if the pigmentation is just from the guts spilling out after death, given how heavily melanized some intestines are?' But from this description it seems to be a genuinely high-contrast cloaca. Delightful.

[Sarapaurolophus]

Someone alert CollectA, they're gonna give their new Psittaco (if they make one) the "dirtiest" cloaka ever.

[stargatedalek]

Not to potentially undermine the reality of the pigmentation, but given this Psittacosaurus is already covered in dark spots this strikes me as a part of the animals overall colour-scheme, I wouldn't go giving CollectA a pass on their highlighted cloacas just yet.

[Tyto_Theropod]

Never did I think I would be reading scientific literature on a dinosaur's 'rude bits', but this is fascinating and unexpectedly inciteful when in comes to how birdlike vs. reptilian Ornithopods were.  The exquisite level of preservation in some fossils, and the amount we can learn from them about animals that died millions of years ago, never ceases to amaze me. 

It's interesting to speculate on any social functions this structure might have had.  I know comparison to mammals isn't ideal, but it reminds me of how animals like deer and Syrian hamsters have highly pigmented secretory scent glands.  On these species the pigmented glands in question are on the sides and legs and are sometimes rubbed against things to indicate that the animal has passed through an area, or assert ownership of a territory.  I doubt you'd want to be deliberately rubbing a part of you that's essential for several bodily functions against rocks and trees, but nonetheless it does make me wonder if there was territoriality involved. 

Another thing I thought of is perhaps one individual Psittacosaurus could get information about another, for example its sex and how healthy it was, by sniffing the cloaca.  As any dog owner will testify, dogs often greet each other by sniffing each others' bottoms, and this is the exact reason they do it.  The glands the dogs are sniffing aren't pigmented or all that conspicuous visually, but I suspect dogs rely more on scent and less on sight than Psittacosaurus did, just as the birds that use cloacal signalling are relying more on sight and less on scent.  If Psittacosaurus had both good vision and a good sense of smell, then maybe the cloacal pigmentation served to highlight the place it could sniff to get information on another Psittacosaurus it had encountered.

But as always, who knows?

[HD-man]

but this is fascinating and unexpectedly inciteful when in comes to how birdlike vs. reptilian Ornithopods were.

@Tyto_Theropod Psittacosaurus is an ornithiscian, not an ornithopod.

[Tyto_Theropod]

Thanks for the correction H @HD-man!  Apparently my keyboard fingers were not working in sync with my brain that day...

[andrewsaurus rex]

wow, incredible stuff....truly awesome.

something that has struck me, the more the colouration of dinosaurs is learned, eg borealopelta, sinosauropteryx, psittacosaurus, is the lack of bright colours, the way so many dinosaurs are depicted in artwork and toys.  In fact the colouration, thus far at least, is rather mammal like with its shades of brown, countershading and contrasty but not colourful patterns eg psittacosaurus' spots and sinsauropteryx' tail stripes and face band.

[BlueKrono]

Open access here


This brief note describes the peculiar V-shaped, pigmented vent of the famous Frankfurt Psittacosaurus specimen that revealed the animal's integument structure and coloration.

I see only a link to "purchase one time access".

[Newt]

I see only a link to "purchase one time access".

How peculiar! That's all I'm seeing now too. Current Biology must have changed their minds about making it open access!