Monday, April 10, 2017

On Reports Of Putative Relict Pterosaurs: A Reappraisal

While I have written about reports of alleged surviving relict pterosaurs on this blog before, I took a mostly critical and sceptical perspective, in which I pointed out that, as the reports do not seem to describe what is now known about pterosaur anatomy from the fossil record, I deem the said reports unlikely to actually be describing living pterosaurs. At the time, I wrote that misidentifications of known animals, such as bats and birds, are likely the main culprits, with perhaps some reports possibly representing encounters with unknown species of birds and bats. However, a recent reappraisal of the situation, spurred by my becoming aware of some more reports that seem to be describing morphological features known in pterosaurs from the fossil record, and that, additionally, are obscure features not known to the average layperson, has inspired me to revisit this topic and reconsider my thoughts on the issue of these purported mystery animals.

On an article (http://www.mysteriousuniverse.org/2016/07/mysterious-living-dinosaurs-of-the-wild-west/) on the weblog Mysterious Universe, the following report is detailed:

"In 2012, another witness claimed to have seen what appeared to be a baby pterodactyl under a bridge in Tucson, Arizona. The winged creature was said to have a wingspan of around 8 feet, and to be covered in whitish fur, with a head sporting a "top knot" that appeared to be molting. The strange creature was apparently quite aggressive towards the intruders, spreading its wings, hissing, and assuming an attack stance."

What immediately stood out to me from this report is that the putative juvenile pterosaur is described as being covered with "whitish fur," much like the pycnofibres (fur-like integumentary structures) that fossils of pterosaurs from the Mesozoic Era show them to have possessed. This is in stark contrast to the other reports which seem to describe scaly- or leathery-skinned winged monsters, with nary a semblance to the actual prehistoric ornithodiran, or avemetatarsalian, archosaurian winged reptiles of the Mesozoic Era. Not only is this feature of the report anatomically accurate, but, notably, pycnofibres are also a relatively obscure anatomical feature that the average layperson, exposed to naked-skinned Flintstones-esque inaccurate portrayals of pterosaurs, would not be overtly familiar with.
This renders the above report more impelling, in my eyes, than most.

Yet another realization I have had is that, as pterosaurs' bones tended to be relatively hollow and lightweight, like those of birds (an adaptation to flight), it would seem less implausible for them to have a 66-million-year-long ghost lineage between the end of the Cretaceous Period and the present-day. The criticism of the idea that surviving prehistoric species might explain cryptozoological encounters has been made that many of the proposed candidates were in possession of large, dense, bones resistant to erosion, whose fossils would not easily leave a ghost lineage. (However, it shall be noted that even this is not necessarily a tightly-binding rule, as there exists a group of ichthyosaurs -- marine reptiles with large, dense, erosion-resistant bones -- for which a 66-million-year-long ghost lineage exists, the same length of time as has elapsed between the end of the Cretaceous Period and now).
As pterosaurs' bones were relatively light, hollow, and fragile, the idea of them leaving a considerable ghost lineage seems to be, on the face of it, by no means absurd.

So I decided it was time for a reappraisal of my views on the matter. I now view the idea of surviving relict populations of the clade Pterosauria, as, by no means confirmed or likely, but not overly implausible or far-fetched, and a possibility that, while ought still to be parsed skeptically, should be considered, rather than rejected outright, when analyzing cryptozoological reports said to describe creatures similar to them.

Bibliography:
Swancer, Brent. 22 July 2016. "Mysterious Living Dinosaurs of the Wild West". Mysterious Universe. http://www.mysteriousuniverse.org/2016/07/mysterious-living-dinosaurs-of-the-wild-west/