Astrodon

Astrodon; Temporal range: Early Cretaceous, 112 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
	Artist's impression
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Saurischia
Suborder:	Sauropodomorpha
Infraorder:	Sauropoda
(unranked):	Titanosauriformes
Genus:	Astrodon; Johnston, 1859
Species
	A. johnstoni Leidy, 1865 (type);

Astrodon (astro: star, don: tooth) was a large genus of herbivorous sauropod dinosaur, related to Brachiosaurus, that lived in what is now the eastern United States during the Early Cretaceous period. Its fossils have been found in the Arundel Formation, which has been dated through palynomorphs to the Aptian-Albian boundary, about 112 million years ago.^[1] Adults are estimated to have been more than 9 m (30 ft) high and 15 to 18 m (50 to 60 ft) long.

Discovery and species

Two teeth were found in the Arundel Formation near Bladensburg, Maryland and named Astrodon in 1859 by Christopher Johnston. However, Johnston did not attach a specific epithet, so Joseph Leidy is credited with naming Astrodon johnstoni (the type species) in 1865. If Johnston had attached a scientific epithet, it would have been the second dinosaur identified in the United States.

In 1888, O.C. Marsh named some bones from the Arundel found near Muirkirk, Maryland Pleurocoelus nanus and P. altus. However, in 1921 Charles W. Gilmore argued that the name Astrodon had priority, a position that Carpenter and Tidwell (2005) accepted in the first in-depth description of this dinosaur. Interestingly, the majority of the bones of Astrodon are of juveniles. Astrodon is sometimes considered a synonym of Pleurocoelus, but the jury is still out on which name is correct. Carpenter and Tidwell therefore consider the two species named by Marsh, nanus and altus, as different growth stages of Astrodon johnsoni.^[1]

Cultural references

In 1998, Astrodon johnstoni was named the state dinosaur of Maryland. Astrodon also appears in the novel Raptor Red by Robert T. Bakker, as prey of Utahraptor.

References

^ ^a ^b Carpenter, Kenneth and Tidwell, Virginia (2005). "Reassessment of the Early Cretaceous Sauropod Astrodon johnsoni Leidy 1865 (Titanosauriformes)". In Carpenter, Kenneth and Tidswell, Virginia (ed.) (ed.). Thunder Lizards: The Sauropodomorph Dinosaurs. Indiana University Press. pp. 38–77. ISBN 978-0-253-34542-4. {{cite book}}: |editor= has generic name (help)CS1 maint: multiple names: authors list (link)

External links

Astrodon at DinoData
Maryland State Archives

[carpenter&tidwell2005-1] Carpenter, Kenneth and Tidwell, Virginia (2005). "Reassessment of the Early Cretaceous Sauropod Astrodon johnsoni Leidy 1865 (Titanosauriformes)". In Carpenter, Kenneth and Tidswell, Virginia (ed.) (ed.). Thunder Lizards: The Sauropodomorph Dinosaurs. Indiana University Press. pp. 38–77. ISBN 978-0-253-34542-4. {{cite book}}: |editor= has generic name (help)CS1 maint: multiple names: authors list (link)

[1]