[D] Gorgosaurus sternbergi
Matthew & Brown, 1923
Cretaceous Late Campanian Maastrichtian
Saurischia Theropoda Tyrannosauria Tyrannosauridae Tyrannosaurinae Albertosaurini
Gorgosaurus > Gorgosaurus libratus (Lambe, 1914) >> Albertosaurus libratus (Lambe, 1914) Gorgosaurus > Gorgosaurus sternbergi (Matthew & Brown, 1923) >> Albertosaurus sternbergi (Matthew & Brown, 1923)
In the 1970s, a major study of the family Tyrannosauridae concluded that Gorgosaurus and Albertosaurus were the same genus, and that the only differences between the two were suggested not only by comparisons of dissimilar growth stages, but also by variations between populations. Albertosaurus was named first, so according to the rules of biological nomonclature, its name had priority. Later work by Phillip Currie at the Royal Tyrrell Museum of Paleontology has shown that these two dinosaurs are, in fact, separate and valid genera.
Gorgosaurus sternbergi is verry a complete specimen (AMNH 5664) from the Late Campanian of Alberta. It is smaller and more slender than Gorgosaurus libratus with less massive jaws, a more slender muzzle, a more slender and elongate maxilla and more circular orbits.
The femur is considerably shorter than the tibia a feature thats possible is age related as G. sternbergi has more juvenile features such as widely open sutures between skull roof bones and non-co-ossified pelvic elements. Russell considers G. sternbergi (Albertosaurus sternbergi) as a juvenile Gorgosaurus libratus (Albertosaurus libratus).