Reconstructing the Cretaceous azhdarchid Keresdrakon

Kellner et al. 2019
presented a new Early or Late Cretaceous (Aptian or Campanian) toothless pterosaur preserved as several 3D bones, far from complete (Fig. 1). Keresdrakon vilsoni (CP.V 2069) was considered an “azhdarchoid pterodactyloid.” Unfortunately, neither clade is monophyletic when more taxa are added in the large pterosaur tree (LPT, 251 taxa). The authors report, “Keresdrakon vilsoni gen. et sp. nov. was recovered as a sister taxon of the tapejaridae.”

Figure 1. All that is known of Keresdrakon layered on top of a Quetzalcoatlus sp. specimen and the same ghosted and reduced to the size of Keresdrakon.

Figure 1. All that is known of Keresdrakon layered on top of a Quetzalcoatlus sp. specimen and the same ghosted and reduced to the size of Keresdrakon.

Perhaps too little of Keresdrakon is preserved
to add it to the LPT, but layering elements atop a previously completed image of the six-foot-tall Quetzalcoatlus specimen results in a pretty close match (Fig. 1). Overall Keresdrakon is about 64% the size of Q. sp. Proportionately manual 4.1 is longer than in Q. sp.

Ontogeny
The authors note, “the presence of these growth marks suggests that this bone belongsto an ontogenetically less developed individual compared to others.”

Figure 8 in Kellner et al. 2019 has a few identification errors.

  1. a is the left ilium, not the left ischium
  2. b and c are ischia, not pubes
  3. d and e are pubes, not ischia

The coracoid identified in Kellner et al. 2020
is not co-osified to the scapula and is relatively small (Fig. 1). In pterosaurs ossification or lack thereof is phylogenetic, not ontogenetic. It’s also worth noting that basal taxa in the Azhdarcho clade also have an unfused scapula and coracoid with the coracoid often much smaller than the scapula. The tiny BSPG 1911 I 31 Solnhofen specimen is one such taxon.

Co-author, Alex Kellner, along with Wann Langston
published Q. sp. in 1996, so it’s a bit surprising that Q. sp. was not immediately seen as a close match to Keresdrakon.

Sympatry
Keresdrakon were found close to the tapejarid Caiuajara in desert sandstone.


References
Kellner AWA and Langston W 1996. Cranial remains of Quetzalcoatlus (Pterosauria, Azhdarchidae) from late Cretaceous sediments of Big Bend National Park, Texas. – Journal of Vertebrate Paleontology 16: 222–231.
Kellner AWA, Weinschütz LC, Holgado B, Bantim RAM and Sayão JM 2019. A new toothless pterosaur (Pterodactyloidea) from Southern Brazil with insights into the paleoecology of a Cretaceous desert. Anais da Academia Brasileira de Ciencias 91: e20190768. DOI 10.1590/0001-3765201920190768

wiki/Quetzalcoatlus
wiki/Keresdrakon

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