Rhabdodontomorpha

Rhabdodontomorpha
Temporal range: Cretaceous, 140–66 Ma
Muttaburrasaurus mount at the Queensland Museum
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: †Ornithischia
Clade: †Neornithischia
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] The clade is characterized by the following synapomorphies:[4]

  • 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.[4] Iani, described in 2023, is interpreted as a transitional taxon between Tenontosaurus and Rhabdodontidae.[5]

  1. ^ Fonseca, André O.; Reid, Iain J.; Venner, Alexander; Duncan, Ruairidh J.; Garcia, Mauricio S.; Müller, Rodrigo T. (2024-12-31). "A comprehensive phylogenetic analysis on early ornithischian evolution". Journal of Systematic Palaeontology. 22 (1). doi:10.1080/14772019.2024.2346577. ISSN 1477-2019.
  2. ^ Poole, Karen (2022). "Phylogeny of iguanodontian dinosaurs and the evolution of quadrupedality". Palaeontologia Electronica. doi:10.26879/702. ISSN 1935-3952.
  3. ^ a b Dieudonné, Paul-Emile; Tortosa, Thierry; Fernández-Baldor, Fidel Torcida; Canudo, José Ignacio; Díaz-Martínez, Ignacio (2016). "An Unexpected Early Rhabdodontid from Europe (Lower Cretaceous of Salas de los Infantes, Burgos Province, Spain) and a Re-Examination of Basal Iguanodontian Relationships". PLOS ONE. 11 (6): e0156251. Bibcode:2016PLoSO..1156251D. doi:10.1371/journal.pone.0156251. PMC 4917257. PMID 27333279.
  4. ^ a b Dieudonné, P.-E.; Cruzado-Caballero, P.; Godefroit, P.; Tortosa, T. (2020-07-20). "A new phylogeny of cerapodan dinosaurs" (PDF). Historical Biology. 33 (10): 2335–2355. doi:10.1080/08912963.2020.1793979. ISSN 0891-2963. S2CID 221854017.
  5. ^ Zanno, Lindsay E.; Gates, Terry A.; Ayrahami, Haviv M.; Tucker, Ryan T.; Makovicky, Peter J. (2023). "An early-diverging iguanodontian (Dinosauria: Rhabdodontomorpha) from the Late Cretaceous of North America". PLOS ONE. 18 (6). e0286042. doi:10.1371/journal.pone.0286042. PMC 10246810. PMID 37285376.