I reported the presence of fluted mesial and lateral teeth, with four to six flutes (possibly more), in Yuanmouraptor in my paper on the distribution of dental features in theropods (Hendrickx et al., 2019). The authors describing this very interesting metriacanthosaurid, however, omit to report this important dental feature in this taxon. Do they consider that the flutes on the labial side of the premaxillary and maxillary teeth (I could not see them in the dentary teeth) of Yuanmouraptor might be due to taphonomic process? If the presence of fluted mesial and lateral teeth in Yuanmouraptor is confirmed by the authors, they can certainly consider this dental feature as an autapomorphy of this taxon among Metricanthosauridae. Indeed, it is, to my knowledge, the only avetheropod with fluted mesial and lateral teeth and the only one among non-spinosaurid Tetanurae. The presence of fluted teeth might also provide information on the dietary preference of this metricanthosaurid given that a fluted dentition is often associated with a piscivorous diet (Hendrickx et al., 2019).

Thank you very much!

Christophe Hendrickx

Reference: Hendrickx C, Mateus O, Araújo R, Choiniere J. 2019. The distribution of dental features in non-avian theropod dinosaurs: Taxonomic potential, degree of homoplasy, and major evolutionary trends. Palaeontologia Electronica 22:1–110. DOI: https://doi.org/10.26879/820. https://palaeo-electronica.org/content/2019/2806-dental-features-in-theropods