Herrerasaurus
| Herrerasaurus Temporal range: Upper Triassic
231.4 mya | |
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| Mounted cast of skeleton, Senckenberg | |
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| Family: | Herrerasauridae
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| Genus: | Herrerasaurus
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Herrerasaurus was one of the earliest dinosaurs. All known fossils of this carnivore have been discovered in Upper Triassic strata dated to 231.4 million years ago (mya) in northwestern Argentina.[1]
It is a member of the Herrerasauridae, a family of similar genera that were among the earliest dinosaurs.[2][3]
Description
[change | change source]Herrerasaurus was a lightly built bipedal carnivore with a long tail and a relatively small head. Its length is estimated at 3 to 6 meters (10 to 20 ft),[4] and its hip height at more than 1.1 meters (3.3 ft).[5] It may have weighed around 210–350 kilograms (463–772 lb).[5]
In a large specimen the skull measured 56 centimeters (1.8 ft) in length.[5] Smaller specimens had skulls about 30 centimeters (1 ft) long.[6]
The tail, partially stiffened by overlapping vertebral projections, balanced the body and was also an adaptation for speed.[6]
Palaeoenvironment
[change | change source]The paleoenvironment of the Ischigualasto Formation (where it was found) was a volcanically active floodplain covered by forests with seasonal rainfall. The climate was moist and warm,[7] with seasonal variations.[8] The vegetation was ferns, horsetails, and giant conifers. These plants formed lowland forests along the banks of rivers.[4] Herrerasaurus was the most common of the carnivores of the Ischigualasto Formation.
Herrerasaurus lived in these jungles alongside a smaller dinosaur, the one metre long Eoraptor. Saurosuchus,[9] a huge quadrupedal Archosaur was the biggest land predator at the time. There were also a number of therapsid and reptilian herbivores. The dinosaurs had not yet taken control of the land environments as they did later.
References
[change | change source]- ↑ Alcober, Oscar A.; Martinez, Ricardo N. (2010). "A new herrerasaurid (Dinosauria, Saurischia) from the Upper Triassic Ischigualasto Formation of northwestern Argentina". ZooKeys (63): 55–81. doi:10.3897/zookeys.63.550. PMC 3088398. PMID 21594020.
- ↑ Nesbitt S.J. et al 2009. (2009). "A complete skeleton of a late Triassic saurischian and the early evolution of dinosaurs". Science. 326 (5959): 1530–1533. Bibcode:2009Sci...326.1530N. doi:10.1126/science.1180350. PMID 20007898. S2CID 8349110.
{{cite journal}}: CS1 maint: numeric names: authors list (link) - ↑ Airhart, Marc 2009. "New meat-eating dinosaur alters evolutionary tree". Jackson School of Geosciences. Archived from the original on 2011-10-02. Retrieved 2014-01-01.
{{cite web}}: CS1 maint: numeric names: authors list (link) - ↑ 4.0 4.1 Sereno P.C. and Novas F.E. 1992. The complete skull and skeleton of an early dinosaur. Science 258 (5085): 1137–1140.
- ↑ 5.0 5.1 5.2 Paul G.S. 1988 Predatory dinosaurs of the world (1989). Predatory Dinosaurs of the World: A Complete Illustrated Guide. New York: Simon and Schuster. pp. 248–250. ISBN 0-671-68733-6.
{{cite book}}: CS1 maint: numeric names: authors list (link) - ↑ 6.0 6.1 Langer, Max C. 2004. Basal Saurischia. In Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds) The Dinosauria. 2nd ed, Berkeley: University of California Press, pp. 25–46. ISBN 0-520-24209-2
- ↑ Tucker, Maurice E.; Benton, Michael J. (1982). "Triassic environments, climates and reptile evolution". Palaeogeography, Palaeoclimatology, Palaeoecology. 40 (4): 361–379. doi:10.1016/0031-0182(82)90034-7.
- ↑ Columbi, Carina E. 2008. Stable isotope analysis of fossil plants from the Upper Triassic Ischigualasto Formation in the northwest of Argentina. Houston, Texas: The Geological Society of America. Archived from the original on 2012-01-11. Retrieved 2014-01-01.
{{cite conference}}: CS1 maint: numeric names: authors list (link) - ↑ Sill, W D; Sill, W. D. (1974). "The anatomy of Saurosuchus galilei and the relationships of the rauisuchid thecodonts". Bulletin of the Museum of Comparative Zoology at Harvard College. 146: 317–362. ISSN 0027-4100.