Hone 2023 looks at the pterosaur ‘sternum’ (= sternal complex)

Somehow
Hone 2023 managed to shed even more darkness on the subject of pterosaurs. This time he considered the sternal complex (= sternum + interclavicle + clavicles, Wild 1993, Fig 1), which Hone called the sternum. Hone combed the literature, examined many specimens and reported what he found, unfortunately without offering any new valid insights. Several times he indicated he was at a loss to explain several basic facts about pterosaurs (see below).

This is never good for someone who considers himself a pterosaur expert.

Example:
“There is only one well-preserved sternum known for any anurognathid and that is in Batrachognathus.”

This is incorrect. Most preserve the sternal complex (Fig 4). Those few that don’t are often exposed in dorsal view with the sternum still buried in the matrix below the ribs awaiting a µCT scan. Unfortunately, Hone is well known for his less than precise tracings and observations (see list below) and unfortunately this pattern continues in this present paper.

Hone 2023 reports,
“The ancestry of pterosaurs has been controversial and difficult to resolve for an extended period (Hone and Benton, 2007; Bennett, 2013b),

Hone is at fault for this as he considered, then ignored the older literature on pterosaur origins (Peters 2000a, b, 2002) ironically featured front and center in Hone and Benton 2007, 2008. So this is a sin of commission, not an accidental oversight. In his 2023 paper Hone also ignored more recent literature (e.g. Peters 2007, 2009, 2011) on pterosaur origins and has rejected a more recent manuscript (2018) available at ResearchGate.net on the subject.

Figure 1. From 2013. Tritosaur pectoral girdles demonstrating the evolution and migration of the sternal elements to produce a sternal complex. Only one of these elements is a sternum.

Hone 2023 continued,
“…but it has recently become clear that pterosaurs are derived archosaurs and lie close to the origin of the Dinosauromorpha.”

Ironically… Hone allied pterosaurs with lepidosaurs on his figure 18 (Fig 2 below) when he presented a Varanus pectoral girdle with an interclavicle and a dinosaur pectoral girdle without one. Hone reported, “I suggest that the interclavicle was smaller and instead forms the cristospine [of the pterosaur sternal complex] alone,” apparently not realizing his inconsistent hypothesis of interrelationships AND taking credit for something that has been known since Wild 1993.

Figure 2. Pectoral girdles from Hone 2023 his figure 18, the lepidosaur, Varanus (left), and the basal theropod dinosaur, Tawa (right). Colors added here.

Not sure why Hone traditionally ignores valid and tested pterosaur outgroups,
like Longisquama and Cosesaurus (Figs 1, 3), that show the pre-sternal complex developing in lepidosaur pterosaur ancestors. Evidently Hone prefers what he was taught in grad school, perhaps not realizing that discovering things like pterosaur ancestors is >his job<. How can Hone claim to be a specialist if Hone has no idea what pterosaurs are or how they are related to other taxa? Sadly, that’s just the start of Hone’s long history of mishaps (see below).

Figure 3. The pectoral elements of Cosesaurus. Coracoids (cyan). Clavicles (magenta). Scapulae (green). Sternum (yellow). Interclavicle (red).

Hone reported,
“The intrarelationships of the pterosaurs remain somewhat uncertain, and controversial and multiple competing hypotheses exist for their phylogeny. It is even unclear for some taxa to which major clade they belong, and other clades may join or leave different branches of the pterosaur tree in different analyses. As such, some of the assignments of taxa used throughout this paper remain uncertain or controversial, and thus it is also difficult to discuss.”

A wide gamut phylogenetic analysis built by Dr Hone would have resolved these many phylogenetic problems. Alas, we’re all still waiting for this.

At the same time, Hone omitted citing any peer-review papers by Peters, who published on pterosaur origins and interrelations several times over the past two decades.

Putting that aside, this is Hone’s job, as a paid pterosaur specialist, to understand the origin and interrelationships of pterosaurs. If interrelationships are indeed uncertain, Dr David Hone should fix that. Otherwise unpaid amateurs will fill this void.

Advice for Dr. Hone:
Stop whatever you’re doing and start building your own LRT. This will answer your questions and provide solutions to your prehistoric problems… or at least give you a good start. Trait-based phylogenetic analysis has revolutionized paleontology and is the foundation for all subsequent hypotheses.

Stop omitting literature that doesn’t fit whatever you were taught under the tutelage of your professor, Mike Benton. You are no longer under his spell. If you disagree with published literature on the origin of pterosaurs, publish a valid argument with a similar taxon list.

Don’t be afraid to trace fossils with colors and reconstruct them. The details you too often overlook (Fig 4) too often matter. This is where the fun is. Rebuilding taxa once lost in time.

David, you spent good money and precious time on your education under the influence of professor Benton. We’re still waiting for you to do something wonderful and valid. You’re young, brash and intelligent. You should be leading the charge, building a list of discoveries, not mired in a list of mistakes. Somehow you have managed to shed darkness on pterosaur anatomy by reporting pterosaurs had a mandibular fenestra, an antorbital fossa, wing membranes that extended to the ankles, wing tips that curved anteriorly. You embraced the quad launch hypothesis, the pterosaurs are archosaurs hypothesis, the allometry of juveniles and agreed with the owl-eyed anurognathid hypothesis. We have yet to see you conduct a wide-gamut phylogenetic analysis or create a precise reconstruction based on your own observations. Unfortunately, you and your old professor Benton will always be known as the two PhDs who un-discovered the origin of pterosaurs. Bennett 2013 called out your mistakes, which you never corrected or acknowledged. Every time you publish you’re twenty years behind the times or you are again creating confusion (Fig 2).

Stop bowing to peer group pressure. You are a scientist! Think for yourself even if that makes you a renegade or a heretic. You’re a PhD and have been for over a decade. You’re well connected. Every museum either knows you or expects to see you soon. It’s time to break out and do something great, or at least valid and novel. Your many past mistakes will then be forgiven, but never forgotten. Unfortunately, that’s your albatross to wear eternally. You took the wrong advice too often when you were young and this pattern of always making the wrong choice has to stop if you are going to make any real progress.

Even so, there’s hope for you yet. Your career should last for several more decades.

Readers: Consider Dr. Hone’s many reports with the tacit understanding
that he traditionally omits pertinent taxa and key literature, generally avoiding his duty to confirm, refute or modify published hypotheses whenever necessary. If Hone disagrees with a hypothesis he generally ignores it rather than refuting it, even though >that’s his job<. In other words, like so many other pterosaur workers, he keeps his blinders on.

Figure 4. Click to enlarge. DGS tracing of Anurognathus ammonia. The sternal complex is in the center of the image (green) rotated more than 90º from its invivo orientation.

By contrast,
the LRT and LPT provide authority and evidence to confirm, refute and modify hypothetical interrelationships. If those are wrong or need modification, I hope other workers will soon show exactly where the problems are with a similar taxon list. Corrections here are a constant. Likewise, DGS tracings provide ideal evidence for identifying elements in the matrix. We should all be coloring every bone in the matrix with a standard palate. Then these can be repaired and corrected whenever necessary… with cooperation, not animosity.

Figure 5. Sternal complex of a pterosaur, probably Altmuehlopterus (formerly Germanodactylus rhamphastinus), not the misspelled Altmulopterus, as indicated in Hone’s caption.

PS
Figure 19 of Hone 2023 presents the ‘sternum of a juvenile Altmulopterus‘. Google does not list this taxon. It might be a typo. If so, it could be Altmuehlopterus rhamphastinus formerly Germanodactylus rhamphastinus (Wagner 1851 B St AS I 745, No. 64 of Wellnhofer 1970), which is not a juvenile.

References
Bennett SC 2013. The phylogenetic position of the Pterosauria within the Archosauromorpha re-examined. Historical Biology 25(5-6): 545-563.
Hone DWE 2023. The anatomy and diversity of the pterosaurian sternum. Palaeontologia Electronica Article number: 26.1.a12 https://doi.org/10.26879/1261
Hone DWE and Benton MJ 2007. An evaluation of the phylogenetic relationships of the pterosaurs to the archosauromorph reptiles. Journal of Systematic Palaeontology 5:465–469.
Hone DWE and Benton MJ 2008. Contrasting supertree and total evidence methods: the origin of the pterosaurs. Zitteliana B28:35–60.
Peters D 2000a. Description and Interpretation of Interphalangeal Lines in Tetrapods. Ichnos 7:11-41.
Peters D 2000b. A reexamination of four prolacertiforms with implications for pterosaur phylogenesis. Rivista Italiana di Paleontologia e Stratigrafia 106: 293–336.
Peters D 2002. A New Model for the Evolution of the Pterosaur Wing – with a twist. Historical Biology 15: 277-301.
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 2009. A reinterpretation of pteroid articulation in pterosaurs. Journal of Vertebrate Paleontology 29: 1327-1330.
Peters D 2011. A Catalog of Pterosaur Pedes for Trackmaker Identification
Ichnos 18(2):114-141. http://dx.doi.org/10.1080/10420940.2011.573605
Wild R 1993. A juvenile specimen of Eudimorphodon ranzii Zambelli (Reptilia, Pterosauria) from the upper Triassic (Norian) of Bergamo. Rivisita Museo Civico di Scienze Naturali “E. Caffi” Bergamo 16: 95-120.

Now it’s Langobardisaurus and the Origin of the Pterosaur Sternal Complex

What exactly IS a pterosaur? – part 3 of 3

A Supertree of Pterosaur Origins (Hone and Benton 2007, 2009)