Open Paleo

Alectrosaurus

Gilmore, 1933 a-LEK-tro-SAWR-us /əˌlɛktroʊˈsɔːrəs/

From Greek 'alektros' meaning 'without a mate' or 'unmarried' (hence 'alone') and 'sauros' meaning 'lizard'; meaning 'alone lizard'

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

Alectrosaurus is a genus of tyrannosauroid theropod dinosaur from the Late Cretaceous Iren Dabasu Formation of Inner Mongolia, China.

Diagnosis

  1. Pedal digit III relatively shorter compared to the length of metatarsal III than in most other tyrannosaurs.
  2. Distinct lip demarcating the posterior border of the distal condyle of metatarsal III, so that the distal articulatory surface is not medially continuous with the shaft as it is in Albertosaurus, Tyrannosaurus, and Struthiomimus.
  3. Flexor tubercles on pedal digits III and IV relatively larger than those of Albertosaurus, extending posteriorly so that they are almost flush with the ventral margin of the articular facet.

Species

Alectrosaurus olseni Gilmore, 1933

Type species

Named for George Olsen, the assistant paleontologist who discovered the first specimens of this dinosaur in Mongolia in 1923.

Lectotype
AMNH 6554 , American Museum of Natural History
Material
A virtually complete right hind limb comprising femur, tibia, fibula, astragalus, calcaneum and pes, with two manual unguals of questionable affinity cataloged under the same number and retained only provisionally.
Notes
Gilmore (1933) founded the species on two cotypes, AMNH 6368 and AMNH 6554, collected from sites about 30 m apart. Mader and Bradley (1989) found the AMNH 6368 forelimb material not to be tyrannosauroid and designated AMNH 6554, the hind limb, as the lectotype.
Horizon
Iren Dabasu Formation, Coniacian–Maastrichtian, Late Cretaceous , 89.8–66.0 million years ago
Locality
site 136, Iren Dabasu, Inner Mongolia, China

References

  1. 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. gilmore1933a
  2. Mader, B. J.; Bradley, R. L. (1989). A redescription and revised diagnosis of the syntypes of the Mongolian tyrannosaur Alectrosaurus olseni. Journal of Vertebrate Paleontology 9(1): 41-55. Informa UK Limited. doi:10.1080/02724634.1989.10011737

    Redescribes the syntypes and designates AMNH 6554 as the lectotype, excluding the AMNH 6368 forelimb material from the genus.

    mader1989a