Archosauria: Avemetatarsalia to Neornithes
2° Nominal Author
The active definition is a first-order revision of the initial definition proposed by Sereno (1998). It uses species rather than genera and also includes the more poorly known
as an additional internal specifier to ensure inclusion of the type species. This species is referable to this clade, despite being listed recently as “Ankylosauria, incertae sedis” (Maryanska et al. 2004).
Inactive Taxon Status
Current Age Range
Callovian (165 Ma)
Maastrichtian (66 Ma)
Basis for Range
The earliest record is
(Callovian), from the Lower Oxford Clay of England. Although listed as “Ankylosauria, incertae sedis” (Maryanska at al. 2004), the lower jaw is referabble to the Nodosauridae (Sereno 1997; unpublished data). The latest well dated record is
transylvanicus from the late Maastrichtian of Romania. Dates are rounded to the nearest million, the earliest from the beginning of the stage and the latest from the end of the stage (Gradstein et al. 2004).
Definitional History #1
All ankylosaurs closer to