| Rhabdodontomorpha Temporal range: Cretaceous, | |
|---|---|
 | |
| Tenontosaurus (background) and Convolosaurus (foreground), both tenontosaurids | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | † Ornithischia |
| Clade: | † Ornithopoda |
| Clade: | † Iguanodontia |
| Clade: | † Rhabdodontomorpha Dieudonné et al., 2016 |
| Subgroups | |
| |
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. [3] In 2021, Daniel Madzia redefined Rhabdodontomorpha in the PhyloCode as "the largest clade containing Rhabdodon priscus , but not Iguanodon bernissartensis and Hypsilophodon foxii ". [4] The clade is characterized by the following synapomorphies: [5]
- 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. [3] In 2020, the Australian iguanodont Fostoria was also found to belong to this clade. [5] The slightly less inclusive Rhabdodontoidea was named by Karen Poole in 2022 and defined by Fonseca and colleagues in 2024 in the PhyloCode as "the largest clade containing Rhabdodon priscus , but not Hypsilophodon foxii , Iguanodon bernissartensis , and Tenontosaurus tilletti ". [6] [7] This clade includes the family Rhabdodontidae and all rhabdodontomorphs closer to them than to the tenontosaurids. [7] Tenontosaurus and its close relatives belong to the family Tenontosauridae, defined in the PhyloCode as "the largest clade containing Tenontosaurus tilletti , but not Hypsilophodon foxii , Iguanodon bernissartensis , and Rhabdodon priscus ". They have been tentatively recovered as basal members of Rhabdodontomorpha, representing a North American radiation of this group. [7] [8] Iani , described in 2023, is interpreted as a transitional taxon between Tenontosaurus and Rhabdodontidae. [8]
