Since the fibers of the neck are all clearly shortening substantially to take up the slack created by the death pose, they have to either be elastic fibers or muscle fibers. The latter seem more likely to me, in light their similarity to bird cervical musculature. Lingham-Soliar do not even attempt to explain these problems, and appear oblivious to the fact that a dorsally located collagen frill should not exhibit linnear fibers while the neck is retracted.
Good observation.
4) They also show a photograph (Fig 4) of the tail of NIGP 127587. Despite claims in the paper, the photograph shows a dorsally located layer (apparently) consisting of dino-fuzz style insulatory structures, and a ventral layer of rigorously parallel non-epidermal fibers that are clearly not dino-fuzz (the taphonomy does not distinguish between collagen/elastin/muscle fiber hypotheses in this specimen like it does in IVPP P12415). Unless it is a trick of the lighting, the photograph seems to indicate the epidermal/insulatory layer is preserved on a more superficial layer of rock than the collagen/muscles fibers are.
Worse yet, the proto-fuzz type fibers clearly extend down most of the way past the tail, indicating it is not a midline stucture.
5) Finally, the tone of the paper is inexcusible (to me).