The skull of Longisquama documented

Yesterday we looked at the sternal complex and pectoral girdle of Longisquama (Sharov 1970). Today we’ll look at the controversial skull. Like the shoulder region, the skull is also covered in skin and scales and maybe… could those be long strands of ptero-hairs (pycnofibers) around the neck? You tell me. If you haven’t bought into the rest of the homologies I presented earlier, you won’t buy into the integumentary homologies. (sigh)

The skull of Longisquama in situ.

Figure 1. The skull of Longisquama in situ. The premaxilla and anterior dentary are largely missing. Otherwise crushing has shifted all the elements, even the transverse palatal and parietal elements, to the parasagittal plane (see figure 2). Also, note the sclerotic ring always gets crushed into the plane of the disk, never, as Bennett (2007) mistakenly reports in his anurognathid, on edge. Sharp-eyed observers should be able to see the windpipe.

In situ the overall shape of the skull is apparent, as are the scleral rings and teeth. For me the antorbital fenestra is clearly visible, though covered with tendrils of integument and underlain with palatal elements (Fig. 2), but for other workers, Like Senter, it is not so apparent, but note his lack of detail (Fig. 2). Note the rich crest of soft tissue arising from the frontals, which produces the longest overlooked plume, along with the gular sac in the throat region.

Do you see an antorbital fenestra? Several, but not all prior workers join you if so.

The skull of Longisquama has portrayed by other workers and as documented here.

Figure 2. The skull of Longisquama has portrayed by other workers and as documented here. The parietal is rotated, giving the impression of two crests. The occiptal region is folded in like a playing card. The antorbital fenestra reveals rotated palatal elements as shown in the reconstruction. Note the more or less cartoony aspects of the prior reconstructions, all lacking the precision and detail of the present tracing (produced with DGS) and the reconstruction, which puts the elements back together in three dimensions with a minimum of distortion.

Yes, the skull is messy,
and skin/scales/fibers obscure much, but the skull is largely complete. A reconstruction of the elements recovers a very pterosaur-like skull that also harkens back to the skull of the ancestral Cosesaurus. Some of the teeth are multicusped. The orbit is large. The palatal view suggests that Longisquama may have enjoyed binocular vision with that narrow snout and wide cranium. Such vision would have been appropriate for a lemur-like leaping reptile, however this is not a trait that basal pterosaurs inherited. The rotated parietals produce the illusion of a double crest, but the reconstruction removes the illusion. The rotated occipital bones help determine the width of the skull. Prior workers did not put the crash scene back together again, but took appearances as is, ignoring the occipital bones, and others. The vestigial quadratojugal extends from the jugal toward the quadrate without making a firm connection to it, again, as in pterosaurs and kin going back to Macrocnemus.

*
I did not put my earlier published interpretations (Peters 2000, 2002) of Longisquama here because they have been shifted to my trash pile in favor of this interpretation, produced with more understanding and a better eye for what lurks there. If anyone wants to talk about how I reconstruct Longisquama, do not rummage through my trash as Darren Naish did in last year’s critique. This is the most recent work. This would have been published several years ago, but reviewers blackballed it for the usual reasons.

If – just – the skull or – just – the skull and forequarters were known,
Longisquama would still nest with Cosesaurus, Sharovipteryx, Kyrgyzsaurus and basal pterosaurs. The rest of the anatomy cements those relationships.

As always, I encourage readers to see specimens, make observations and come to your own conclusions. Test. Test. And test again.

Evidence and support in the form of nexus, pdf and jpeg files will be sent to all who request additional data.

For those interested, PterosaurHeresies gets between 200 and 400 hits per day with about half that many unique visitors. The Lesothosaurus is a rhynchosaur post stands out as a recent exception with twice those numbers.

References
Sharov AG 1970. A peculiar reptile from the lower Triassic of Fergana. Paleontologiceskij Zurnal (1): 127–130.

wiki/Longisquama

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