Open Paleo

Heterodontosaurus

Crompton & Charig, 1962 HET-e-ro-DON-to-SAWR-us

From Greek 'heteros' meaning 'different', 'odont' meaning 'tooth', and 'sauros' meaning 'lizard', in reference to its unusual heterodont dentition. The species name honors George C. Tuck, who supported the expedition.

199.5–184.2 million years ago Sinemurian–Pliensbachian, Early Jurassic
Early Jurassic stages

Heterodontosaurus is a genus of heterodontosaurid dinosaur that lived during the Early Jurassic, 200-190 million years ago. Its only known member species, Heterodontosaurus tucki, was named in 1962 based on a skull discovered in South Africa. The genus name means "different toothed lizard", in reference to its unusual, heterodont dentition; the specific name honors G. C. Tuck, who supported the discoverers. Further specimens have since been found, including an almost complete skeleton in 1966.

Diagnosis

  1. Short facial region with large antorbital fenestra
  2. Supraorbital bone projecting into orbit
  3. Hinder premaxilla with three teeth: two incisor-like and one large caniniform
  4. Wide diastema between premaxillary and maxillary teeth
  5. About 12 closely-set maxillary teeth with vertical ridging on distal halves of crowns
  6. First mandibular tooth large and caniniform, projecting upward into diastema
  7. Mandibular teeth closely-set with vertical ridges, enamel on inner surface only
  8. Predentary present without teeth, separated from dentary by distinct suture

Species

Heterodontosaurus tucki Crompton & Charig, 1962

Type species

Named for George C. Tuck, a director of Austin Motor Company who financially supported the British-South African expedition that recovered the holotype.

Holotype
SAM-PK-K337 , Iziko South African Museum
Material
Partial skeleton with almost complete skull and lower jaw.
Horizon
lower Clarens Formation, Sinemurian–Pliensbachian, Early Jurassic , 199.5–184.2 million years ago
Locality
Tyindini trading store, Eastern Cape, South Africa Kitching and Raath published the coordinate in 1984, and Norman and colleagues (2011) reprint it. They also supply the Clarens name for what Crompton and Charig (1962) call the Cave Sandstone. Sereno (2012) places the holotype in "lower levels" of the Clarens, which is Sinemurian to Pliensbachian below its topmost beds. The referred skeleton SAM-PK-K1332 comes from "the upper part of the Elliot Formation" at Voyizane, "stratigraphically lower than the horizon at which the holotype was found" (Norman and colleagues 2011), dated Hettangian to Sinemurian by Bordy and colleagues (2020). The stages follow the holotype's horizon, not this older one.

Notable specimens

  • SAM-PK-K1332

    Iziko South African Museum Found 1966 most complete

    The most complete heterodontosaurid skeleton described to date. Found at the Voyizane locality, it preserves skull and skeleton in articulation with little displacement, and as an adult underpins the full description of the genus's anatomy.

    Santa Luca (1980)Norman et al. (2011)

  • AM 4766

    Albany Museum Found 2005 complementary

    A very complete specimen found near Grahamstown. Its rock was too hard to remove, so it was synchrotron-scanned in 2016; the data on its pelvis and gastralia underpinned a 2021 reinterpretation of ornithischian breathing, with Heterodontosaurus as an intermediate stage.

    Radermacher et al. (2021)

  • SAM-PK-K10487

    Iziko South African Museum ontogeny

    The front part of a juvenile skull, the key ontogenetic specimen for the genus, showing that the eye sockets became proportionally smaller and the snout longer with age. CT scans revealed unerupted replacement teeth even at this early stage, informing the tooth-replacement debate.

    Butler et al. (2008)

  • SAM-PK-K1334

    Iziko South African Museum ontogeny

    A left maxilla from the Voyizane locality. Its upper jaw was the first specimen in which unerupted replacement teeth were discovered in Heterodontosaurus, a find later corroborated by the juvenile skull AMNH 24000.

    Norman et al. (2011)

References

  1. Crompton, A. W.; Charig, A. J. (1962). A new Ornithischian from the Upper Triassic of South Africa. Nature 196(4859): 1074-1077. Springer Science and Business Media LLC. doi:10.1038/1961074a0 crompton1962a
  2. Paul, G. S. (2024). The Princeton Field Guide to Dinosaurs (3rd ed.). Princeton University Press.

    Source of the appearance features.

    paul2024a
  3. Santa Luca, A. P. (1980). The postcranial skeleton of Heterodontosaurus tucki (Reptilia, Ornithischia) from the Stormberg of South Africa. Annals of the South African Museum 79(7): 159-211. santaluca1980a
  4. Norman, D. B.; Crompton, A. W.; Butler, R. J.; Porro, L. B.; Charig, A. J. (2011). The Lower Jurassic ornithischian dinosaur Heterodontosaurus tucki Crompton & Charig, 1962: cranial anatomy, functional morphology, taxonomy, and relationships. Zoological Journal of the Linnean Society 182-276. doi:10.1111/j.1096-3642.2011.00697.x norman2011a
  5. Radermacher, V. J.; Fernandez, V.; Schachner, E. R.; Butler, R. J.; Bordy, E. M.; Naylor Hudgins, M.; de Klerk, W. J.; Chapelle, K. E. J.; Choiniere, J. N. (2021). A new Heterodontosaurus specimen elucidates the unique ventilatory macroevolution of ornithischian dinosaurs. eLife 10: e66036. doi:10.7554/eLife.66036 radermacher2021a
  6. Butler, R. J.; Porro, L. B.; Norman, D. B. (2008). A juvenile skull of the primitive ornithischian dinosaur Heterodontosaurus tucki from the 'Stormberg' of southern Africa. Journal of Vertebrate Paleontology 28(3): 702-711. doi:10.1671/0272-4634(2008)28[702:AJSOTP]2.0.CO;2

    Described the juvenile skull SAM-PK-K10487 and referred it to Heterodontosaurus tucki on shared autapomorphies.

    butler2008a
  7. Sereno, P. C. (2012). Taxonomy, morphology, masticatory function and phylogeny of heterodontosaurid dinosaurs. ZooKeys 226: 1-225. Pensoft Publishers. doi:10.3897/zookeys.226.2840

    Places the holotype in "lower levels" of the Clarens Formation.

    sereno2012a
  8. Bordy, E. M.; Abrahams, M.; Sharman, G. R.; Viglietti, P. A.; Benson, R. B. J.; McPhee, B. W.; Barrett, P. M.; Sciscio, L.; Condon, D.; Mundil, R.; Rademan, Z.; Jinnah, Z.; Clark, J. M.; Suarez, C. A.; Chapelle, K. E. J.; Choiniere, J. N. (2020). A chronostratigraphic framework for the upper Stormberg Group: implications for the Triassic-Jurassic boundary in southern Africa. Earth-Science Reviews 203: 103120. doi:10.1016/j.earscirev.2020.103120

    Dates the upper Elliot Formation, source of SAM-PK-K1332, to the Hettangian–Sinemurian and the Clarens to a mainly Pliensbachian age.

    bordy2020a