Rhabdodontomorpha is a

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

of basal

iguanodont Iguanodontia (the iguanodonts) is a clade of herbivorous dinosaurs that lived from the Middle Jurassic to Late Cretaceous. Some members include ''Camptosaurus'', ''Dryosaurus'', ''Iguanodon'', '' Tenontosaurus'', and the hadrosaurids or "duck-bil ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

s. This group was named in 2016 in the context of the description, based on Spanish findings of an early member of the

Rhabdodontidae Rhabdodontidae is a family of herbivorous iguanodontian ornithopod dinosaurs whose earliest stem members appeared in the middle of the Lower Cretaceous. The oldest dated fossils of these stem members were found in the Barremian Castrillo de la R ...

. A

cladistic analysis Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived chara ...

was conducted in which it was found that ''

Muttaburrasaurus ''Muttaburrasaurus'' was a genus of herbivorous iguanodontian ornithopod dinosaur, which lived in what is now northeastern Australia sometime between 110 and 103 million years agoHoltz, Thomas R. Jr. (2012) ''Dinosaurs: The Most Complete, Up-to ...

'' 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 ''Rhabdodon'' (meaning "fluted tooth") is a genus of ornithopod dinosaur that lived in Europe approximately 70-66 million years ago in the Late Cretaceous. It is similar in build to a very robust "hypsilophodont" (non-iguanodont ornithopod), thou ...

'' Matheron, 1869 and ''Muttaburrasaurus langdoni'' Bartholomai and Molnar, 1981; and all its descendants. Within the clade ''

Zalmoxes ''Zalmoxes'' is an extinct genus of rhabdodontid ornithopod dinosaur from the Maastrichtian of Romania. The genus is known from specimens first named as the species '' Mochlodon robustum'' in 1899 by Franz Nopcsa before being reclassified as ...

'' and ''

Mochlodon ''Mochlodon'' is a genus of rhabdodontid dinosaurs from the Late Cretaceous of Austria and Hungary. It lived during the Late Cretaceous (85-80 Ma) and two species are known: ''M. suessi'' and ''M. vorosi''. Discovery and species In 1859 coal ...

'' are also included. The clade is characterized by the following synapomorphies: * 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 Gondwana () was a large landmass, often referred to as a supercontinent, that formed during the late Neoproterozoic (about 550 million years ago) and began to break up during the Jurassic period (about 180 million years ago). The final stages ...

. It must have split from other iguanodont groups during the Middle Jurassic. In 2020, the Australian iguanodont '' Fostoria'' was also found to belong to this clade.

References

{{Taxonbar, from=Q24765920 Iguanodonts Aptian first appearances Maastrichtian extinctions