An article regarding the discovery of a new T-rex relative from Alaska:
http://www.science20.com/news_articles/nanuqsaurus_hoglundi_alaskas_pigmy_t_rex-131592
The timing of the description of Nanuqsaurus surprised me, but it's no surprise that N. hoglundi shows that the diversity of Edmontonian tyrannosaurs was greater than previously thought, given that Albertosaurus and Nanuqsaurus lived about the same time and belong to different subfamilies of T. rex. The discovery of Nanuqsaurus also lends support to the hypothesis that the ancestors of T. rex emigrated to North America from Asia via Beringia.
The article describing Nanuqsaurus is as follows:
Anthony R. Fiorillo & Ronald S. Tykoski (2014)A Diminutive New Tyrannosaur from the Top of the World.PLoS ONE 9(3): e91287.doi:10.1371/journal.pone.0091287http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0091287