forward pointing pubic bone. Another basal character is the lack of a bulla, a swollen region on the underside of the braincase. This indicates that the similar bulla with the Ornithomimosauria presents a case of parallel evolution and is not a proof for a Bullatosauria, an earlier presumed close relationship between troodontids and ornithomimosaurs. Originally, the basal position of Sinovenator seemed to be corroborated by a very high age, the fossils being assumed to date from the Hauterivian. Later research however, indicated that the layers were younger. In 2017, a study by Shen et al., describing the genus Daliansaurus found Sinovenator to form a monophyletic group with other troodontids from the Yixian Formation, named Sinovenatorinae. A wide, flattened fourth metatarsal was found to be a synapomorphy uniting this group. The study recovered the following cladogram: A 2018 study by Yin et al. instead found the Chinese troodontids to form an intermediate grade: See also Timeline of troodontid research References Early Cretaceous dinosaurs of Asia Troodontids Fossil taxa described in 2002 Taxa named by Xu Xing Yixian fauna