Genasauria

Skeletal reconstruction of Agilisaurus louderbacki, copyright Jaime A. Headden.

Belongs within: Dinosauria.
Contains: Stegosauria, Ankylosauria, Ornithopoda, Pachycephalosauria, Ceratopsia.

The Genasauria are a major clade of herbivorous dinosaurs that have been defined as uniting the Thyreophora (armoured dinosaurs), Ornithopoda and Marginocephalia (pachycephalosaurs and ceratopsians). All Ornithischia surviving after the early Jurassic are members of this clade. Basal genasaurs include Lesothosaurus diagnosticus, a lightly built bipedal species about two metres in length from the early Jurassic of southern Africa.

Synapomorphies (from Butler et al. 2007): Metacarpals with proximal ends not block-like; manual phalanges/metacarpals with at least some extensor pits on dorsal surface of distal end absent or poorly developed; manual unguals not strongly recurved, without prominent flexor tubercle; brevis shelf and fossa with fossa facing ventrolaterally, visible in lateral view along entire length, creating deep postacetabular portion.

<==Genasauria BSN07
    |--+--Lesothosaurus Galton 1978 ZY09, NWW04a
    |  |    `--L. diagnosticus Galton 1978 NWW04a
    |  `--Thyreophora NWW04b
    |       |  i. s.: Tatisaurus Simmons 1965 NWW04b
    |       |           `--T. oehleri Simmons 1965 [=Scelidosaurus oehleri] NWW04b
    |       |         Bienosaurus Dong 2001 NWW04b
    |       |           `--B. lufengensis Dong 2001 NWW04b
    |       |         Lusitanosaurus de Lappaarent & Zbyszewski 1957 NWA04b, D07
    |       |           `--L. liasicus Lapparent & Zbyszewski 1957 (n. d.) NWW04b
    |       |--Laquintasaura venezuelae BNB17
    |       |--Scutellosaurus Colbert 1981 NWW04b
    |       |    `--S. lawleri Colbert 1981 NWW04b
    |       `--+--Emausaurus Haubold 1991 NWW04b
    |          |    `--E. ernsti Haubold 1991 NWW04b
    |          `--+--Scelidosaurus Owen 1860 NWW04b
    |             |    `--S. harrisonii Owen 1861 NWW04b
    |             `--Eurypoda [Thyreophoroidea] NWW04b
    |                  |--Stegosauria NWW04b
    |                  `--Ankylosauria NWW04b
    `--Neornithischia [Euornithopoda] BSN07
         |  i. s.: Atlascopcosaurus Rich & Rich 1989 NS04
         |           `--A. loadsi Rich & Rich 1989 NS04
         |         Gongbusaurus NS04
         |           |--G. shiyii Dong, Zhou & Zhang 1983 (n. d.) NWW04a
         |           `--G. wucaiwanensis Dong 1989 NS04
         |         Notohypsilophodon Martínez 1998 NS04
         |           `--N. comodorensis Martínez 1998 NS04
         |         Qantassaurus Rich & Vickers-Rich 1999 NS04
         |           `--Q. intrepidus Rich & Vickers-Rich 1999 NS04
         |         Yandusaurus He 1979 NS04
         |           `--Y. hongheensis He 1979 NS04
         |--Stormbergia dangershoeki BSN07
         `--+--Agilisaurus Peng 1990 BSN07, NS04
            |    |--A. louderbacki Peng 1990 NS04
            |    `--A. multidens (He & Cai 1983) [=Yandusaurus multidens] NS04
            `--+--Hexinlusaurus multidens BSN07
               `--+--Othnielosaurus celer BSN07
                  `--Cerapoda BSN07
                       |--Ornithopoda BSN07
                       `--Marginocephalia BSN07
                            |--Pachycephalosauria BSN07
                            `--Ceratopsia BSN07

*Type species of generic name indicated

REFERENCES

[BNB17] Baron, M. G., D. B. Norman & P. M. Barrett. 2017. A new hypothesis of dinosaur relationships and early dinosaur evolution. Nature 543: 501–506.

[BSN07] Butler, R. J., R. M. H. Smith & D. B. Norman. 2007. A primitive ornithischian dinosaur from the Late Triassic of South Africa, and the early evolution and diversification of Ornithischia. Proceedings of the Royal Society of London Series B—Biological Sciences 274 (1621): 2041–2046.

[D07] Dixon, D. 2007. The Complete Illustrated Encyclopedia of Dinosaurs & Prehistoric Creatures. Hermes House: London.

[NS04] Norman, D. B., H.-D. Sues, L. M. Witmer & R. A. Coria. 2004. Basal Ornithopoda. In: Weishampel, D. B., P. Dodson & H. Osmólska (eds) The Dinosauria 2^nd ed. pp. 393–412. University of California Press: Berkeley.

[NWW04a] Norman, D. B., L. M. Witmer & D. B. Weishampel. 2004a. Basal Ornithischia. In: Weishampel, D. B., P. Dodson & H. Osmólska (eds) The Dinosauria 2^nd ed. pp. 325–334. University of California Press: Berkeley.

[NWW04b] Norman, D. B., L. M. Witmer & D. B. Weishampel. 2004b. Basal Thyreophora. In: Weishampel, D. B., P. Dodson & H. Osmólska (eds) The Dinosauria 2^nd ed. pp. 335–342. University of California Press: Berkeley.

[ZY09] Zheng, X.-T., H.-L. You, X. Xu & Z.-M. Dong. 2009. An Early Cretaceous heterodontosaurid dinosaur with filamentous integumentary structures. Nature 458: 333–336.

Last updated: 6 August 2017.