mandible suture. Philip J. Currie in 1990 also concluded to a malformation, thinking the flattened side resulted from the tooth remaining attached too long to the inner wall of the tooth-socket. Serrated specimens of the type would thus simply be deviant dromaeosaurid teeth; however, unserrated teeth might represent a separate taxon or taxa. One study, by Sunny Hwang, showed that the tooth enamel is identical to that found in Byronosaurus, a troodontid known from juveniles with serration-less teeth. Several taxa have on occasion been considered synonyms of Paronychodon, though there is little consensus. Paronychodon was in 1876 by Cope described as being similar to Zapsalis, another tooth taxon, itself often considered synonymous with Richardoestesia, a possible dromaeosaurid. Richardoestesia isosceles would, according to a study by Julia Sankey e.a., be synonymous with the elongated, so-called "Type A", teeth of Paronychodon, to which also the Paronychodon holotype belongs. The Eurasian Euronychodon tooth genus is also sometimes considered a (junior) synonym of Paronychodon. See also Timeline of troodontid research References Troodontids Late Cretaceous dinosaurs of North America Campanian genus first appearances Maastrichtian genus extinctions Maastrichtian life Lance fauna Paleontology in Montana Laramie Formation Early Cretaceous dinosaurs of Europe Cretaceous Spain Fossils of Spain La Huérguina Formation Fossil taxa described in 1876 Taxa named by Edward Drinker Cope