Lythronax

First discovered‭ ‬in‭ ‬2009‭ ‬and officially named in November‭ ‬2013,‭ ‬stratigraphical analysis of the Lythronax holotype remains has led to them being estimated as being deposited around‭ ‬80.6‭ ‬to‭ ‬79.9‭ ‬million years ago.‭ ‬This makes Lythronax one of the oldest tyrannosaurids known in North America,‭ ‬and at least‭ ‬2‭ ‬million years older than Teratophoneus which is also known from the Kaiparowits Formation but from an estimated date of‭ ‬77‭ ‬to‭ ‬76‭ ‬million years ago.
      A key feature of Lythronax that is instantly visible from looking at the skull is the rostrum that is comparatively short when compared to those of the majority of other tyrannosaurid genera.‭ ‬Lythronax however is not unique in having a proportionately short rostrum in that two other tyrannosaurid genera known from what is now the south western United States,‭ ‬Bistahieversor and Teratophoneus,‭ ‬are also known to have had rostrums that were proportionately shorter than those of tyrannosaurids living in the northern United States and Asia.‭
      These three genera may yet contribute to a growing pattern of shorter snouted tyrannosaurs‭ ‬living in the South West of the United States developing shorter rostrum either to meet differing ecological conditions,‭ ‬or perhaps even as a result of their populations being isolated from those in the north,‭ ‬resulting in differing traits being established between the northern and southern tyrannosaurs of the United States.‭ ‬Another possibility however is that the short snouts of these genera may be primitive forms that had disappeared in more developed
Category:Dinosaurs
Category:Cretaceous Animals
Category:Extinct Animals
Category:Mesozoic Animals