Link:
https://www.academia.edu/126691661/Nanotyrannus_as_an_Eutyrannosaurian_Abstract_
Abstract
Throughout 2024, several publications have shed new light on the highly-debated tyrannosauroid taxon Nanotyrannus lancensis, or as this author calls it, Nanotyrannus/Dryptosaurus lancensis. Nanotyrannus has been placed outside of tyrannosauridae, and into the basal tyrannosauroidea clade. Even more surprising, the holotype of Nanotyrannus, CMNH 7541, had an external fundamental system (EFS) located within its hyoid. This indicates that the specimen was an adult. Although we now have a mature specimen for the species, this author raises a question: where does Nanotyrannus lie within tyrannosauroidea? There are two groups within the basal tyrannosauroidea clade: pantyrannosauria and eutyrannosauria. Based on the skeletal characteristics Nanotyrannus shares with Raptorex, Dryptosaurus, and Appalachiosaurus, and since the latter two taxa are within eutyrannosauria, this author hypothesizes that Nanotyrannus can be placed within eutyrannosauria. This author also believes that Raptorex, another debated tyrannosaur, could fit within eutyrannosauria as well. Another potential member is the Bissekty tyrannosauroid. A possible hypothetical growth series for Nanotyrannus could be the following: BMRP 2002.4.1 (“Jane”), BMRP 2006.4.4 (“Petey”), and CMNH 7541.