Alectrosaurus olseni Gilmore, 1923

Christopher A. Brochu, 2003, Osteology of Tyrannosaurus rex: insights from a nearly complete skeleton and high-resolution computed tomographic analysis of the skull, Journal of Vertebrate Paleontology 22, pp. 1-138 : 4

Alectrosaurus olseni Gilmore, 1923 —The holotype (AMNH 6554) is a left hindlimb and foot, with a portion of the pubic boot, from what is now the People’s Republic of China. The original description by Gilmore (1923) included some forelimb material, but as shown by Mader and Bradley (1989), this was not directly associated with the hindlimb and is now regarded as representing a therezinosauroid.

The hindlimb is likely that of a tyrannosaurid based on the arctometatarsalian metapodials and enlarged femoral trochanters. A box of bone fragments (AMNH 6266) from the same locality includes small tyrannosaurid skull bones (including a characteristic jugal, lacrymal, quadratojugal, and D-shaped premaxillary tooth) that might belong to the same individual. These had been originally catalogued as “Deinodon sp.” (an older name applied to large theropods, including tyrannosaurids), but this was subsequently scratched off and “Theropoda indet.” written on in pencil. The skull parts are consistent with Albertosaurus', for example, the jugal foramen is a dorsallyopening slit.

Perle (1977) later described material from a different locality in Mongolia that included a skull. Because this material was not available for study, it has not been considered in this analysis. Figures in Perle’s description are not very detailed, but the material is evidently well-preserved, and more has since been collected (Currie, 2000a).