Open Paleo

Ornithopoda

Marsh, 1881

Its genera lived 165.3–66.0 million years ago Middle Jurassic–Late Cretaceous

Ornithopoda, meaning "bird feet," is a clade of ornithischian dinosaurs that includes the iguanodonts and hadrosaurs along with a range of smaller, more basal members. Known worldwide, ornithopods were among the most successful herbivorous dinosaurs of the Cretaceous, ranging from small, fast-running Jurassic bipeds to the large quadrupedal duck-billed hadrosaurs, some of which grew as heavy as medium-sized sauropods before dying out in the end-Cretaceous extinction. Their key evolutionary advantage was a progressively refined chewing apparatus, ultimately the most sophisticated of any non-avian dinosaur, that let them process tough plant material through a grinding, transverse jaw action. They are further distinguished by their characteristic bird-like feet, the lack of body armor, an elongated pubis, and the absence of an opening in the lower jaw. Early forms were mainly browsers or fruit-eaters, while larger, more derived members were bulk feeders capable of subsisting on coarse, low-nutrient vegetation.

Diagnosis

  1. Pleurokinetic skull permitting lateral rotation of the maxillae during chewing
  2. Jugal positioned well above the level of the quadrate condyles
  3. Lowered mandibular glenoid, offsetting the jaw joint below the tooth row
  4. Dentary crowns lacking a primary labial swelling; dentary tooth roots curved
  5. Elongate prepubic process of the pubis

Clades within Ornithopoda

Genera placed directly in Ornithopoda

  • Ampelognathus Tykoski et al., 2023 Cenomanian (100.5–93.9 Ma)United Statesincertae sedisunder dispute
  • Burianosaurus Madzia et al., 2017 Cenomanian (100.5–93.9 Ma)Czechia
  • Changmiania Yang et al., 2020 Barremian (125.8–121.4 Ma)China
  • Convolosaurus Andrzejewski et al., 2019 Aptian (121.4–113.2 Ma)United Statesincertae sedisunder dispute
  • Fulgurotherium Nomen dubium Huene, 1932 Cenomanian (100.5–93.9 Ma)Australiaincertae sedis
  • Gideonmantellia Ruiz-Omeñaca et al., 2012 Barremian (125.8–121.4 Ma)Spainincertae sedisunder dispute
  • Weewarrasaurus Bell et al., 2018 Cenomanian (100.5–93.9 Ma)Australiaincertae sedisunder dispute

References

  1. Marsh, O. C. (1881). Classification of the Dinosauria. American Journal of Science 23(133): 81-86. American Journal of Science. doi:10.2475/ajs.s3-23.133.81

    Erected Ornithopoda; read before the National Academy of Sciences in November 1881 and published in 1882.

    marsh1881a
  2. Madzia, D.; Arbour, V. M.; Boyd, C. A.; Farke, A. A.; Cruzado-Caballero, P.; Evans, D. C. (2021). The phylogenetic nomenclature of ornithischian dinosaurs. PeerJ 9: e12362. doi:10.7717/peerj.12362

    Provides the modern phylogenetic definition of Ornithopoda.

    madzia2021a