Variation in Rhamphorhynchus 2024: more myth, no analysis

Mike Habib and David Hone teamed up to
look at several Rhamphorhynchus specimens. They reported, “These specimens cover a wide range of sizes and ontogenetic states (Bennett, 1995) and include both young juveniles and unusually large adults,”

Actually only one juvenile (the Vienna specimen Fig 1) was found in the midst of a few dozen Rhamphorhynchus specimens described by Peters (ResearchGate.net preprint 2015). The discrepancy comes from Habib and Hone not recognizing that pterosaurs are lepidosaurs with isometric (not allometric) growth strategies in which hatchlings are ready to fly, which everyone in pterosaurs recognizes. Neither author has performed the phylogenetic analysis that demonstrates this.

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=”wp-image-45713 size-full” 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 2. Rhamphorhynchus specimens to scale. The Lauer Collection specimen would precede the Limhoff specimen on the second row. This has been online for several years here.

The authors cited Hone et al 2020,
when they wrote, “Through its ontogeny, Rhamphorhynchus was highly isometric (Hone et al., 2020) presenting a remarkably consistent growth trajectory across a four-fold range of length and over a hundred specimens. We follow Bennett (1995) in considering all specimens of Rhamphorhynchus to belong to a single species, R. muensteri, and therefore, we consider our analysis to be intraspecific.”

See figure 1. These are not all the same species. Only the juvenile and adult (the Vienna specimen and one of the largest specimens (Peters preprint) had the same scores in analysis. THAT indicates isometry. By making the small primitive specimens juveniles that indicates allometry, which is wrong.

The authors state,
“Given that the fifth toe is integrated with the uropatagium as part of the flight apparatus,”

That is no a given. That is false. No pterosaur preserves this.
That fifth toe morphology is identical in Cosesaurus and Tanystropheus, BTW.

The authors’ figure 2
presents seven Rhapmphorhychus pedal 5.2 phalanges. The caption states, “Variation in toe curvature showing exceptional intraspecific differences likely attributable to post-mortem effects.”

This is false. The data indicates variation. Hone and Habib hope to explain it away. Hone is infamous for wing membrane “shrinkage” to fit a preconceived notion, rather than following the data. Habib cheated pterosaur manus morphology to produce his infamous quad-leap hypothesis.

Hone and Habib 2015
twisted the wingtips of pterosaurs anteriorly, not recognizing taphonomy at work.

Hone and Habib 2024
had a data set, much of it from Wellnhofer 1975, but did not produce a phylogenetic analysis.

Do not make these same mistakes in you own studies. Don’t live in their bubble of misunderstanding. Build your own LRT and LPT. Then you’ll know.

New pterosaur wingtip paper: Hone et al. 2015

Hone et al. 2020 vs. Rhamphorhynchus

References
Hone DWE, Van Rooijen and Habib MB 2015.The wingtips of the pterosaurs: Anatomy, aeronautical function and ecological implications. Palaeogeography, Palaeoclimatology, Palaeoecology (advance online publication) doi:10.1016/j.palaeo.2015.08.046
Habib MB and Hone DW 2024. Intraspecific variation in the pterosaur Rhamphorhynchus muensteri—implications for flight and socio-sexual signaling. PeerJ 12:e17524 https://doi.org/10.7717/peerj.17524
Hone DWE, Ratcliffe JM, Riskin DK, Hemanson JW and Reisz RR 2020. Unique near isometric ontogeny in the pterosaur Rhamphorhynchus suggests hatchlings could fly. Lethaia. Paywall access here.
Peters D 2007. The origin and radiation of the Pterosauria. In D. Hone ed. Flugsaurier. The Wellnhofer pterosaur meeting, 2007, Munich, Germany. p. 27.
Peters D unpublished. First juvenile Rhamphorhynchus recovered by phylogenetic analysis. researchgate.net/publication
Wellnhofer P 1975a-c. Teil I. Die Rhamphorhynchoidea (Pterosauria) der Oberjura-Plattenkalke Süddeutschlands. Allgemeine Skelettmorphologie. Paleontographica A 148: 1-33. Teil II. Systematische Beschreibung. Paleontographica A 148: 132-186. Teil III. Paläokolgie und Stammesgeschichte. Palaeontographica 149:1-30.

rhamphorhynchus-to-scale.htm