Montanazhdarcho
Montanazhdarcho is a genus of azhdarchoid pterosaur from the Late Cretaceous period (Campanian stage) of what is now the state of Montana, United States. Montanazhdarcho is known from only one species, M. minor.
Montanazhdarcho | |
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Reconstructed skeletons | |
Scientific classification ![]() | |
Kingdom: | Animalia |
Phylum: | Chordata |
Order: | †Pterosauria |
Suborder: | †Pterodactyloidea |
Clade: | †Azhdarchoidea |
Genus: | †Montanazhdarcho Padian, de Ricqlès & Horner, 1995 |
Type species | |
†Montanazhdarcho minor Padian, Ricqlès & Horner, 1995 |
History and etymology
The genus was named in 1993 by Kevin Padian, Armand de Ricqlès, and Jack Horner,[1] again published by the same authors in 1995[2] and fully described in 2002.[3]

The type species is Montanazhdarcho minor. The generic name refers to the state of Montana and to the related species Azhdarcho. The specific name means "the smaller one" in Latin, a reference to the relatively small size in comparison to closely related forms.
Description
The holotype specimen of Montanazhdarcho, MOR 691 (Museum of the Rockies), was found by Robert W. Harmon in Glacier County, in the territory of the Blackfoot, in sandstone of the Upper Two Medicine Formation, a layer about 74 million years old. The fossil is largely uncompressed and that of an adult exemplar, as established by a study of the bone by de Ricqlès. It consists of a partial left wing, lacking the outer three wing finger phalanges, a complete shoulder girdle, a crushed cervical vertebra and two fragments of the symphysis of the mandible. The jaws were edentulous, i.e. they lacked teeth.
Classification
Montanazhdarcho was by the authors assigned to the Azhdarchidae, mainly based on the elongated form of the neck vertebra. Compared to other azhdarchids however, it was small; the fragments of humerus, radius, and carpal suggest an animal with a 2.5 meter wingspan (8 ft). Its ulna was longer than the wing metacarpal, which is atypical for azhdarchids. In addition to this, a phylogenetic study in 2015 has disagreed to its phylogenetic position, and reassigned Montanazhdarcho as a non-azhdarchid azhdarchoid.[4] However, in 2018, Nicholas Longrich and colleagues had recovered Montanazhdarcho within the Azhdarchidae again, though placed in the basalmost position. Their phylogenetic analysis is shown below:[5]
Azhdarchidae |
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References
- Padian, K., Horner, J.R., and de Ricqlès, A.J. (1993). "A new azhdarchid pterosaur from the Two Medicine Formation (Late Cretaceous, Campanian) of Montana, identified on the basis of bone histology." Journal of Vertebrate Paleontology, 13: 52A
- K. Padian, A. J. de Ricqlès, and J. R. Horner (1995), "Bone histology determines identification of a new fossil taxon of pterosaur (Reptilia: Archosauria)", Comptes Rendus de l’Academie des Science, Serie II (320): 77-84
- McGowen, M.R.; Padian, K.; de Sosa, M.A.; Harmon, R.J. (2002). "Description of Montanazhdarcho minor, an azhdarchid pterosaur from the Two Medicine Formation (Campanian) of Montana". PaleoBios. 22 (1): 1–9.
- Carroll, Nathan (2015). "Reassignment of Montanazhdarcho minor as a non-azhdarchid member of the Azhdarchoidea". Journal of Vertebrate Paleontology. 35: 104.
- Longrich, N.R.; Martill, D.M.; Andres, B.B. (2018). Late Maastrichtian pterosaurs from North Africa and mass extinction of Pterosauria at the Cretaceous-Paleogene boundary. PLoS Biology, 16(3): e2001663. doi:10.1371/journal.pbio.2001663