Pterosaur tail vanes: more useful when they are not flying

Jagielska et al 2024 published a preprint online that revealed
“a cross-linking lattice within the tail vanes of early pterosaurs. The lattice supported a sophisticated dynamic tensioning system used to maintain vane stiffness, allowing the whole tail to augment flight control and the vane to function as a display structure.”

This study used methods similar to an earlier one that
‘shed new light’ (= laser stimulated fluorescence) on the trapezius muscles preserved between the neck and shoulders of a Pterodactylus specimen (Pittman et al 2021).

For the present 2024 study the authors reported,
“Over 100 Solnhofen pterosaur fossils were examined for well-preserved tail vanes using an ultraviolet torch. Four exceptional specimens were then imaged under Laser-Stimulated Fluorescence (LSF). Three specimens exhibited tail vanes under white light but the vane of NHMUK PV OR 37003 was only visible under LSF.”

Tail vanes are more or less different in a variety of pterosaurs (Figs 1-5) and thus can be used to help distinguish species and genera, both in the Mesozoic and today.

Tail vane animation on the C5 specimen of Campylognathoides. ” data-image-caption=”

Figure 1. Click to animate. Tail vane animation on the C5 specimen of Campylognathoides zitteli.

” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2011/10/c5vane-swing.gif?w=300″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2011/10/c5vane-swing.gif?w=584″ tabindex=”0″ role=”button” class=”size-full wp-image-2541″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2011/10/c5vane-swing.gif” alt=”Tail vane animation on the C5 specimen of Campylognathoides.” width=”584″ height=”547″ />

Figure 1. Click to animate. Tail vane animation on the C5 specimen of Campylognathoides zitteli.

The origin of pterosaur tail vanes
goes back to Longisquama (Fig 2). Vanes are eye-catching {to other pterosaurs) secondary sexual traits. In flight vanes act like weather vanes, passively keeping the tail in the path of the air stream. This was important because pterosaurs essentially lost the caudofemoral muscles that other tetrapods use to flex the femur. This flexion also pulls the muscular tail from side to side. So that ability was lost in pterosaurs, which could only raise and lower the tail, which was about a flexible as long fiberglass fishing rod.

The Jagielska et al preprint does not get into the origin of the tail vane nor the attenuation of the tail in pterosaurs, nor the restrictions on tail movement, but focuses on the details in the three tail vanes revealed by laser stimulated fluorescence.

Figure 2. Flapping Longisquama with the acme of plume development in this clade.

Unfortunately
the tail tips of Bergamodactylus (Fig 3) Cosesaurus (Fig 3) and Sharovipteryx extend off the matrix, now lost. Even so Cosesaurus has caudal filaments up and down the entire length of its tail. These evolve to low extended vanes, like those seen in Sordes and Pterorhynchus (Fig 5) and tall tail tip vanes, like those seen in Rhamphorhynchus (Figs 5, 6) and Campylognathoides (Fig 1).

Figure 2. Bergamodactylus, the basal-most pterosaur compared to scale with Cosesaurus and Dromomeron. ” data-image-caption=”

Figure 2. Bergamodactylus, the basal-most pterosaur compared to scale with Cosesaurus and Dromomeron.

” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2024/03/bergamodactylus-dromomeron588.jpg?w=174″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2024/03/bergamodactylus-dromomeron588.jpg?w=584″ tabindex=”0″ role=”button” class=”size-full wp-image-85059″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2024/03/bergamodactylus-dromomeron588.jpg” alt=”Figure 2. Bergamodactylus, the basal-most pterosaur compared to scale with Cosesaurus and Dromomeron.” width=”584″ height=”1005″ />

Figure 3. Bergamodactylus, the basal-most pterosaur compared to scale with Cosesaurus and Dromomeron, an unrelated taxon that some paleontologists say are related to pterosaurs.

Preprints invite response.
They are pre-peer reviewed publications, online at ResearchGate.net within a day.

Sort of like my unpublished manuscripts on ResearchGate.net.
The differences between the two types of publishing are now indistinguishable.

Figure 2. Pterorhynchus with soft tissue. ” data-image-caption=”

Figure 2. Pterorhynchus with soft tissue.

” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2015/06/pterorhynchus588-1.jpg?w=169″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2015/06/pterorhynchus588-1.jpg?w=577″ tabindex=”0″ role=”button” class=”size-full wp-image-38371″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2015/06/pterorhynchus588-1.jpg” alt=”Figure 2. Pterorhynchus with soft tissue.” width=”584″ height=”1036″ />

Figure 4. Pterorhynchus with soft tissue.

I responded via email to co-author Michael Pittman:
“From Peters 2001 (not cited): “The tail vane on a pterosaur would have acted passively, like a weather vane, keeping the tail near the parasagittal plane in turns and during gusts of wind. It would have made a poor steering device compared to simple banking of the wings.”

Figure 6. Illustration of Rhamphorhynchus from Jagielska et al 2024 preprint that underemphasizes the wings and overemphasizes the tail vane of this Rhamphorhynchus pterosaur. ” data-image-caption=”

Figure 6. Illustration of Rhamphorhynchus from Jagielska et al 2024 preprint that underemphasizes the wings and overemphasizes the tail vane of this Rhamphorhynchus pterosaur.

” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2024/07/tailvane-rhamphorhynchus588.jpg?w=300″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2024/07/tailvane-rhamphorhynchus588.jpg?w=584″ tabindex=”0″ role=”button” class=”size-full wp-image-87354″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2024/07/tailvane-rhamphorhynchus588.jpg” alt=”Figure 6. Illustration of Rhamphorhynchus from Jagielska et al 2024 preprint that underemphasizes the wings and overemphasizes the tail vane of this Rhamphorhynchus pterosaur.” width=”584″ height=”312″ />

Figure 5. Illustration of Rhamphorhynchus from Jagielska et al 2024 preprint that underemphasizes the wings and overemphasizes the tail vane of this Rhamphorhynchus pterosaur. My comments on this follow.

Figure 2. Rhamphorhynchus specimens to scale. The Lauer Collection specimen would precede the Limhoff specimen on the second row. ” data-image-caption=”

Figure 2. Rhamphorhynchus specimens to scale. The Lauer Collection specimen would precede the Limhoff specimen on the second row.

” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2020/06/rhamphorhynchus-to-scale588-1.jpg?w=209″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2020/06/rhamphorhynchus-to-scale588-1.jpg?w=584″ tabindex=”0″ role=”button” class=”size-full wp-image-45713″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2020/06/rhamphorhynchus-to-scale588-1.jpg” alt=”Figure 2. Rhamphorhynchus specimens to scale. The Lauer Collection specimen would precede the Limhoff specimen on the second row.” width=”584″ height=”837″ />

Figure 6. Rhamphorhynchus specimens to scale. The Lauer Collection specimen would precede the Limhoff specimen on the second row. Click here to enlarge.

References
Jagielska N et al (4 co-authors) 2024 preprint. New soft tissue data of pterosaur tail vane reveals sophisticated, dynamic tensioning usage and expands its evolutionary origins. bioRxiv preprint doi: https://doi.org/10.1101/2024.07.01.601487
ResearchGate.net online
Peters D 2001. A New Model for the Evolution of the Pterosaur Wing – with a twist. – Historical Biology 15: 277–301.
Pittman M, Barlow LA, Kaye TG, Habib MB 2021. Pterosaurs evolved advanced aerodynamic smoothing of the wing-body junction and sophisticated wing base control to improve flight performance. PNAS 118(44): 225 e2107631118.