So let’s pretend
that the back half of Longisquama was never present in the fossil. Pretend, like Jimmy Stewart in a Wonderful Life, that I was never born.
Now the onus
goes back to all the pterosaur workers who still refuse to examine the very pterosaurian traits of Longisquama, as traced by Sharov (1970, Fig. 1). Those traits are still there, whether I point them out or not.
So many fantasy creatures
have been built around the idea of Longisquama (just Google it), but no one has taken Sharov’s blueprint and put the bones back into their in vivo positions — until now (Fig. 1). When you repeat this experiment, you will also get something that can be input into phylogenetic analysis. And the rest (the blue areas) can be guesstimated based on phylogenetic bracketing. Almost all other artists put much smaller hind limbs on Longisquama, but that’s not what close relatives have (Fig. 1).
Like a basal pterosaur Longisquama has this suite of characters:
- an antorbital fenestra
- a large orbit
- multicusped teeth
- short neck (eight cervicals)
- 9th vert has short rib, 10th vert has rib that contacts sternal complex
- strap-like scapula
- narrow coracoid
- sternal complex (clavicles wrapped around sternum + interclavicle)
- parallel ulna and radius
- asymmetric manus with short digit 5
- structured membrane trails forelimb (proto-wing)
- small membrane precedes forelimb (proto-propatagium)
Everything else we’ll call guesswork
based on phylogenetic bracketing, which is, by definition, extremely conservative. Phylogenetic bracketing gives Longisquama long hind limbs, uropatagia, an attenuated tail and a short mt5 + elongated p5.1, just like it’s sisters.
Sharov’s traits alone
are enough to call this specimen out as the best candidate for pterosaur kinship — and yet — it’s been ignored and dismissed for forty years — even with that PR bump in 2000 and 2002. With such data widely available, does anyone else think it is very odd that professionals who write pterosaur books (Wellnhofer, Witton and Unwin) and other professors (Bennett, Padian, Hone, etc. etc.) claim we don’t know the ancestry of pterosaurs? Or am I the only one who finds this odd and unsettling?
I can understand why they would ignore me, a published amateur widely despised and ridiculed. But why ignore Sharov?
Evidently it’s a mind set.
And it’s hard to break, even with Sharov’s own images. He saw what I saw. I just added details.
Bennett SC 2008. Morphological evolution of the forelimb of pterosaurs: myology and function. Pp. 127–141 in E. Buffetaut & D.W.E. Hone (eds.), Flugsaurier: pterosaur papers in honour of Peter Wellnhofer. Zitteliana, B28.
Peters D 2000. A Redescription of Four Prolacertiform Genera and Implications for Pterosaur Phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106 (3): 293–336.
Peters D 2002. A New Model for the Evolution of the Pterosaur Wing – with a twist. Historical Biology 15: 277-301.
Senter P 2003. Taxon Sampling Artifacts and the Phylogenetic Position of Aves. PhD dissertation. Northern Illinois University, DeKalb, IL, 1-279.
Senter P 2004. Phylogeny of Drepanosauridae (Reptilia: Diapsida) Journal of Systematic Palaeontology 2(3): 257-268.
Sharov AG 1970. A peculiar reptile from the lower Triassic of Fergana. Paleontologiceskij Zurnal (1): 127–130.