Eopteranodon yixianensis enters the LPT closer to Sinopterus benxiensis

Zhang et al. bring us
a new Early Cretaceous pterosaur from China they named Eopteranodon yixianensis (Fig 1), a new species distinct from the holotype Eopteranodon lii (Fig 1). The authors made numerous verbal, graphic and mathematical comparisons, but presented no phylogenetic analysis.

When added to
the large pterosaur tree (LPT, 267 taxa) ?Eopteranodon yixianensis nested closer to Sinopterus benxiensis rather then the Eopteranodon holotype (Fig 1) which continues to nest between germanodactylids and dsungaripterids + tapejards on one branch, and pteranodontids on the other branch. So Eopteranodon is more primitive.

The authors reported,
“Eopteranodon lii, the first tapejarid from the Yixian Formation, was formerly referred to the Pteranodontidae and is now assigned to the Tapejaridae.”

The LPT does not confirm that reassignment
It’s always better to let the software decide where taxa nest, rather than to ‘assign’ taxa to a clade. In this case the new specimen is indeed a member of the Tapejaridae and it needs a new generic name. The holotype specimen of Eopteranodon continues to be an outgroup to Tapejaridae + Dsungateripteridae and related taxa.

The authors also reported,
“as to judge for the bone texture of several bones (e.g., left femoral head) and the unfused nature of others, such as the scapula and coracoid, the epiphysis of the humerus, the extensor tendon process of the first wing phalanx, carpals, sacral vertebrae, pelvic girdle, fibula and tibia and tarsals, the specimen accounts for a juvenile individual.”

This is another erroneous attribution.
In the LPT all related taxa also lack fusion of the scapula and coracoid, the carpals and sacrals, etc. And these taxa are all about the same size (Fig 1).

This is why phylogenetic analysis and graphic reconstruction are so important.

Moreover, the authors are under the traditional invalid impression that pterosaurs are archosaurs and develop under archosaur ‘rules’. This is incorrect. By simply adding taxa pterosaurs nest with lepidosaurs and thus lay leathery lepidosaur eggs, retain lepidosaur embyros and develop ontogenetically under lepidosaur rules as documented by Maisano 2002a,b. This is important work not cited by pterosaur workers.

Taxon exclusion continues to be the number one problem in paleontology.
The LPT minimizes taxon exclusion by including 237 pterosaur taxa. That number includes tested and validated outgroup taxa from the LRT. All competing analyses omit so many pertinent taxa that their topologies vary between folly and myth. Their refusal to add pertinent taxa continues to undercut their presentations.

Build your own LPT to test this for yourself. I hate to see PhDs continue to make the same mistakes decade after decade.

It’s also rare to find precise skeletal reconstructions
in pterosaur papers. That’s unfortunate. Workers traditionally avoid this step, not realizing it makes explaining a hypothesis and a taxon easier for readers to understand than traditional paragraphs of description and bar charts of measurements.

References
Maisano JA 2002a. The potential utility of postnatal skeletal developmental patterns in squamate phylogenetics. Journal of Vertebrate Paleontology 22:82A.
Maisano JA 2002b.Terminal fusions of skeletal elements as indicators of maturity in squamates. Journal of Vertebrae Paleontology 22: 268–275.
Zhang X, Jiang S, Kellner AWA, Cheng X, Costa FR and Wang X 2023. A new species of Eopteranodon (Pterodactyloidea, Tapejaridae) from the Lower Cretaceous Yixian Formation of China. Cretaceous Research https://doi.org/10.1016/j.cretres.2023.105573.