Tyrannosaurinae

Lore & Background

The first remains of tyrannosaurids were uncovered by the Geological Survey of Canada, with scattered teeth named Deinodon by Joseph Leidy in 1856. In 1892 Edward Drinker Cope described isolated vertebrae as Manospondylus gigas, later found to belong to Tyrannosaurus rex. In 1905 Henry Fairfield Osborn described two specimens from Montana and Wyoming, initially naming them Dynamosaurus imperiosus and Tyrannosaurus rex, but recognized them as the same species; Tyrannosaurus was used due to page priority. The second described tyrannosaurine, Tarbosaurus, was originally named Tyrannosaurus bataar by Evgeny Maleev in 1955 after a skull from a Soviet-Mongolian expedition to the Gobi Desert. The genus Tarbosaurus was also described that year based on another specimen, and in 1965 A.K. Rozhdestvensky recognized them as the same species, recombining it as Tarbosaurus bataar. In the 1970s, Daspletosaurus was described by Dale Russell from a partial skeleton found in 1921 near Steveville, Alberta, and Alioramus was described by Sergei Kurzanov from a partial skull found in the Gobi Desert. From 1977 to 2009, several genera were named but are controversial as they likely represent juvenile individuals of Tarbosaurus or Tyrannosaurus. Valid genera named in the 2010s include Teratophoneus (2011), Zhuchengtyrannus (2011), Nanuqsaurus (2014), Qianzhousaurus (2014), and Lythronax (2013).

Reader's Guide

Tyrannosaurinae represents a significant subfamily within Tyrannosauridae, encompassing some of the most iconic and well-studied theropod dinosaurs. Their fossils, found exclusively in Late Cretaceous deposits of western North America and east Asia, provide key insights into the evolution of large predatory dinosaurs. The subfamily includes both the oldest known tyrannosaurid, Lythronax, and the youngest and most famous, Tyrannosaurus rex. Tyrannosaurines were generally more robust and larger than albertosaurines, though the alioramins were gracile with long snouts. Their discovery history spans over a century, from early fragmentary teeth and vertebrae to nearly complete skeletons. Controversies over naming priority (e.g., Manospondylus gigas vs. Tyrannosaurus rex) and the validity of several genera based on juvenile specimens highlight the challenges in tyrannosaurine taxonomy. The subfamily's systematics have been debated, with some researchers proposing a multispecies Tyrannosaurus genus, though this is not widely accepted. Their ecological role as apex predators is supported by their large heads, heterodont dentition, and short didactyl arms. The presence of feathers in tyrannosaurids is controversial, with skin impression studies suggesting a scaly, crocodile-like integument. Tyrannosaurines likely underwent ontogenetic changes, occupying different ecological niches as they matured. Their temporal range from the Campanian to the Maastrichtian stages of the Late Cretaceous makes them key to understanding end-Cretaceous ecosystems.

Did You Know?

• The first tyrannosaurid remains were scattered teeth named Deinodon by Joseph Leidy in 1856.
• Manospondylus gigas, described by Edward Drinker Cope in 1892, was later found to belong to Tyrannosaurus rex and had naming priority, but was overlooked.
• The name Tyrannosaurus was used over Dynamosaurus because it appeared one page earlier in Henry Fairfield Osborn's 1905 article.
• Several genera named between 1977 and 2009, such as Nanotyrannus and Raptorex, are controversial and likely represent juvenile individuals of Tarbosaurus or Tyrannosaurus.