Open Paleo

Astrodon

Leidy, 1865 ahs-tro-don

From Greek 'astron' meaning 'star' and 'odon' meaning 'tooth', referring to the star-like cross-sectional pattern seen in its tooth enamel.

121.4–100.5 million years ago Aptian–Albian, Early Cretaceous
Early Cretaceous stages

Astrodon is a genus of large herbivorous sauropod dinosaur, measuring 20 m (66 ft) in length, 9 m (30 ft) in height and 20 metric tons (22 short tons) in body mass. It lived in what is now the eastern United States during the Early Cretaceous period, and fossils have been found in the Arundel Formation, which has been dated through palynomorphs to the Albian about 112 to 110 million years ago.

Diagnosis

  1. Crown shaft straight, compressed cylindroid, ovate in transverse section
  2. Outer side strongly convex, inner side much less convex
  3. Summit compressed conical, curved inward, convex externally, depressed internally, sub-acute at lateral borders
  4. Dentine interior with multitude of minute tubuli radiating from narrow elliptical pulp cavity
  5. Thick enamel layer surrounding pulp cavity and dentine in transverse section

Species

Astrodon johnstoni Leidy, 1865

Type species

Named for Christopher Johnston, the dentist and professor at Baltimore Dental College who first studied and named the genus in 1859.

Holotype
YPM 798 , Yale Peabody Museum of Natural History
Material
Greater part of tooth crown (~1.5 in long) and transverse section of another tooth from Cretaceous iron ore bed.
Horizon
Arundel Formation, Aptian–Albian, Early Cretaceous , 121.4–100.5 million years ago
Locality
Iron ore bed near Bladensburg, Maryland, United States

Synonyms of the genus

Name Type Reason
Astrodonius junior objective Material is indistinguishable from Astrodon and is treated as a junior synonym.
Astrodontaurus junior objective Original genus name proposed by Johnston, who shortened it to Astrodon for the published 1859 description.

References

  1. Johnston, C. (1859). Note upon odontology. The American Journal of Dental Science, new series 9: 337-343.

    Genus authority: Johnston named Astrodon (genus) in this paper based on tooth morphology but did not designate a species. The type species A. johnstoni was named separately by Leidy (1865).

    johnston1859a
  2. Leidy, J. (1865). Cretaceous reptiles of the United States. Smithsonian Contributions to Knowledge 14: 1-135. Smithsonian Institution. doi:10.5962/bhl.title.39830 leidy1865a