Rhabdodontomorpha
Rhabdodontomorpha
Clade of iguanodont dinosaurs
Rhabdodontomorpha is a clade of basal iguanodont dinosaurs. This group was named in 2016 in the context of the description, based on Spanish findings of an early member of the Rhabdodontidae. A cladistic analysis was conducted in which it was found that Muttaburrasaurus was the sister species of the Rhabdodontidae sensu Weishampel. Therefore, Paul-Emile Dieudonné, Thierry Tortosa, Fidel Torcida Fernández-Baldor, José Ignacio Canudo and Ignacio Díaz-Martínez defined Rhabdodontomorpha as a nodal clade: the group consisting of the last common ancestor of Rhabdodon priscus Matheron, 1869 and Muttaburrasaurus langdoni Bartholomai and Molnar, 1981; and all its descendants. Within the clade Zalmoxes and Mochlodon are also included.[1] The clade is characterized by the following synapomorphies:[2]
- the outline of the dorsal iliac margin is sigmoidal in dorsal view, with the postacetabular process deflected medialward and the pre-acetabular process deflected laterally
- the dorsal iliac margin is mediolaterally broader and swollen from above the ischiac peduncle anteriorly (present in Muttaburrasaurus) or above the postacetabular process all along (present in Zalmoxes spp.)
- the presence of a weak, dorsally convex ridge on the ventromedial side of their postacetabular process
- the ischiac peduncle of the ilium is lenticular and uniquely anteroposteriorly long
- the acetabulum is noticeably low
The group consists of small to large plant eaters from Europe and Gondwana. It must have split from other iguanodont groups during the Middle Jurassic.[1] In 2020, the Australian iguanodont Fostoria was also found to belong to this clade.[2] Iani, described in 2023, is interpreted as a transitional taxon between Tenontosaurus and Rhabdodontidae.[3]