Open Paleo

Gilmoreosaurus

Brett-Surman, 1979 GIL-mohr-o-SAWR-us

Charles Whitney Gilmore's lizard; named in honor of American paleontologist Charles Whitney Gilmore, combined with Greek sauros (lizard)

89.8–66.0 million years ago Coniacian–Maastrichtian, Late Cretaceous
Late Cretaceous stages

Gilmoreosaurus is a genus of hadrosauromorphan dinosaur from the Late Cretaceous of Asia. The type species is Gilmoreosaurus mongoliensis, known from the Iren Dabasu Formation of Inner Mongolia. Additional specimens have been described as distinct species, including G. atavus from the Khodzhakul Formation of Uzbekistan, and G. arkhangelskyi from the Bissekty Formation, also of Uzbekistan. However, these are based on very fragmentary remains, and their classification is dubious. An additional species, G. kysylkumense, also from the Bissekty Formation, is sometimes included, though it has also been referred to the related genus Bactrosaurus.

Diagnosis

  1. Paddle-shaped postacetabular process of the ilium, less than 70% of the length of the iliac central plate.
  2. Ilium combining an ischial tuberosity with a supraacetabular process whose apex lies posterodorsal to the ischial peduncle (a unique combination within Hadrosauroidea).
  3. Manual phalanx III-1 with a strongly asymmetrical distal articular surface.

Species

Gilmoreosaurus mongoliensis (Gilmore, 1933)

Type species

First named as Mandschurosaurus mongoliensis

Named for Mongolia, where the holotype material was discovered in the Iren Dabasu Formation of Inner Mongolia.

Lectotype
AMNH FARB 30735 , American Museum of Natural History
Material
Complete right ilium.
Notes
Prieto-Márquez & Norell (2010) recataloged the former AMNH 6551 type lot — disarticulated bones of at least four individuals — into individual specimen numbers (AMNH FARB 30653-30773) and designated the right ilium AMNH FARB 30735 as the lectotype; the remaining elements, with the predentary AMNH 6369 (Gilmore's cotype), form the hypodigm.
Horizon
Iren Dabasu Formation, Coniacian–Maastrichtian, Late Cretaceous , 89.8–66.0 million years ago
Locality
Quarry 149, Inner Mongolia, China Quarry 149 was opened by the Central Asiatic Expeditions decades before the genus was named.

Synonyms

  • Mandschurosaurus mongoliensis reassigned

    Original combination (Gilmore, 1933). Brett-Surman (1979) erected the new genus Gilmoreosaurus to accommodate this species after Mandschurosaurus amurensis was identified as a nomen dubium.

References

  1. Brett-Surman, M. K. (1979). Phylogeny and palaeobiogeography of hadrosaurian dinosaurs. Nature 277(5697): 560-562. Springer Science and Business Media LLC. doi:10.1038/277560a0 brett-surman1979a
  2. Gilmore, C. W. (1933). On the dinosaurian fauna of the Iren Dabasu Formation. Bulletin of the American Museum of Natural History 67(2): 23-78.

    Original description of the species as Mandschurosaurus mongoliensis on cotype material AMNH 6551 and AMNH 6371 from the Iren Dabasu Formation, Inner Mongolia.

    gilmore1933a
  3. Prieto-Márquez, A.; Norell, M. A. (2010). Anatomy and relationships of Gilmoreosaurus mongoliensis (Dinosauria, Hadrosauroidea) from the late Cretaceous of Central Asia. American Museum Novitates (3694): 1-49. American Museum of Natural History. doi:10.1206/3694.2

    Redescription of the recataloged type material; designates the lectotype AMNH FARB 30735, emends the diagnosis, and recovers G. mongoliensis as a non-hadrosaurid hadrosauroid close to Hadrosauridae.

    prieto-márquez2010b