Sinopterus? or Huaxiapterus? It gets confusing…

A kind reader alerted me to a misidentification here.
The grayscale image (Fig. x) is the ZMNH M 8131 specimen of Huaxiapterus. When a higher resolution image becomes available I will return to this specimen and edit the copy. With that in mind… here is the original blogpost, awaiting an edit.

Figure x. Huaxiapterus ZMNH-M-8131 specimen.. 

 

Thank goodness
for museum numbers.

Today the ZMNH M 8131 specimen first attributed to
Huaxiapterus corollatus (Lü et al. 2006) then renamed Sinopterus corollatus (Zhang et al. 2019; Figs. 1, 2) enters the the large pterosaur tree (LPT, 255 taxa) basal to tapejarids, derived from the Sinopterus atavismus specimen nesting basal to dsungaripterids.

Figure 1. Huaxiapterus corollatus ZMNH M 8131 reconstructed. An alternate m4.1 is provided that looks more like a m4.1 than a metacarpal 4.

Sometimes specimens are reassembled slightly wrong.
In this case several long bones were accidentally reversed end-to-end in this otherwise stunning mount. One never knows what the original fossil looked like prior to reassembly. We don’t want to call these ‘fakes’. We do want to be aware of errors and artistic reconstructions as much as is possible.

Figure 2. The ZMNH specimen in situ and somewhat corrected for original perspective issues. The correction makes the wings the same length. Be wary of such wonderful-looking fossils. This specimen appears to have been reassembled. Some long bones are reversed end-to-end, which do not affect scoring.

Sinopterus – Huaxiapterus corollatus (Lü et al. 2006; Early Cretaceous, ZMNH M 8131) is another largely complete specimen with confusing nomenclature. This taxon nests at the base of the Tapejara, basal to the Aathal specimen (below). The pelvis is missing. The sternum is among the largest of all pterosaurs. The cervicals are longer creating a taller pterosaur.

From the Lü et al. abstract:
“A new species of tapejarid pterosaur, Huaxiapterus corollatus sp. nov. is erected on the basis of a nearly complete skull and postcranial skeleton from the Lower Cretaceous Jiufotang Formation of Liaoning Province, China. Huaxiapterus corollatus sp. nov. is characterized by a hatchet-shaped rectangular process on the premaxilla, whose short axis is perpendicular to the anterior margin of the premaxillae. Except for this process, other characters of the skull such as the breadth of the snout between the anterior margin of the nasoantorbital fenestra and the anterior margin of the premaxilla are similar to that of Huaxiapterus jii.”

Figure 3. Huaxiaptrus iii and Huaxiapterus corollatus to scale. These two do not nest next to one another in the LPT.

The Lü et al. abstract continues
“Huaxiapterus and a second Chinese tapejarid, Sinopterus, share several unique cranial characters in common with Tapejara and these three genera appear to be more closely related to each other than to other azhdarchoids.

In the LPT azhdarchids nest with dorygnathids, not tapejarids. Adding these taxa missing from prior studies makes this inevitable.

“The Chinese tapejarids (Sinopterus and Huaxiapterus) have relatively elongate skulls and weakly developed cranial crests and seem to be less derived than Tapejara, with its shorter, deeper skull and large cranial crest. Tupuxuarids (Tupuxuara and Thalassodromeus) have often been associated with tapejarids in the family Tapejaridae, but this relationship is controversial because some phylogenetic analyses have supported the pairing of tupuxuarids with Azhdarchidae.”

Adding taxa moves Azhdarchidae away from tupuxuarids.

Figure 4. Tapejaridae in the LPT.

“We propose that Tapejaridae be restricted to Tapejara, Sinopterus and Huaxiapterus.”

The LPT does not support that proposal (Fig. 4). The Tapejaridae remains a monophyletic clade in the LPT derived from dsungaripterids, shenzhoupterids and earlier, germanodactylids… not azhdarchids.

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References
Lü JC, Jin XS, Unwin DM, Zhao LJ, Azuma Y and Ji Q 2006. A new species of Huaxiapterus Pterosauria: Pterodactyloidea from the Lower Cretaceous of western
Liaoning, China with comments on the system atics of tapejarid pterosaurs. Acta Geol Sinica English 80: 315-326.
Zhang X, Jiang S, Cheng X and Wang X 2019. New material of Sinopterus (Pterosauria, Tapejaridae) from the Early Cretaceous Jehol Biota of China. Anais da Academia Brasileira de Ciencias 91(2):e20180756. DOI 10.1590/0001-3765201920180756.

wiki/Sinopterus
wiki/Huaxiapterus
reptileevolution.com/tapejaridae.htm