and troodonts into a coelurosaurian clade called Arctometatarsalia based on a common ankle structure where the second and fourth metatarsals meet near the tarsal bones, covering the third metatarsal when viewed from the front. Basal tyrannosauroids like Dilong, however, were found with non-arctometatarsalian ankles, indicating that this feature evolved convergently. Arctometatarsalia has been dismantled and is no longer used by most paleontologists, with tyrannosauroids usually considered to be basal coelurosaurs outside Maniraptoriformes. While many place tyrannosauroids as basal coelurosaurs, Paul Sereno in his 1990s analysis of theropods would find the Tyrannosaurs to be sister taxa to the Maniraptora with them being closer to birds than Ornithomimosaurs were. He called this group Tyrannoraptora (which in the absence of papers that recover a Tyrannosaur-maniraptoran clade), is a clade which contains most Coelurosaurs. A 2007 analysis found the family Coeluridae, including the Late Jurassic North American genera Coelurus and Tanycolagreus, to be the sister group of Tyrannosauroidea. The most basal tyrannosauroid known from complete skeletal remains is Guanlong, a representative of the family Proceratosauridae. Other early taxa include Stokesosaurus and Aviatyrannis, known from far less complete material. The better-known Dilong is considered slightly more derived than Guanlong and Stokesosaurus. Dryptosaurus, long a difficult genus to classify, has turned up in several recent analyses as a basal tyrannosauroid as well, slightly more distantly related to Tyrannosauridae than Eotyrannus and Appalachiosaurus. Alectrosaurus, a poorly known genus from Mongolia, is definitely a tyrannosauroid but its exact relationships are unclear. Other taxa have been considered possible tyrannosauroids by various authors, including Bagaraatan and Labocania. Siamotyrannus from the Early Cretaceous of Thailand was originally described as an early tyrannosaurid, but is usually considered a carnosaur today. Iliosuchus has a vertical ridge on the ilium reminiscent of tyrannosauroids and may in fact be the earliest known member of the superfamily, but not enough material is known to be sure. Below is a cladogram by Loewen et al. in 2013 that included most tyrannosauroid species known at the time of its publication. Phylogeography In 2018 authors Rafael Delcourt and Orlando Nelson Grillo published a phylogenetic analysis of Tyrannosauroidea which incorporated taxa from the ancient continent of Gondwana (which today consists of the southern hemisphere), such as Santanaraptor and Timimus, whose placement in the group has been controversial. They have found that not only Santanaraptor and Timimus were placed as tyrannosaurs more derived than Dilong, but they have found in their