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Dinosaurs: Four Legs Good, Two Legs Bad
P Martin Sander1, Jens N Lallensack2
1Steinmann Institute of Geology, Mineralogy and Paleontology, University of Bonn, Nussallee 8, 53115 Bonn, Germany; The Dinosaur Institute, Natural History Museum of Los Angeles County, Los Angeles, CA, USA.
Current Biology : CB
|October 10, 2018
Summary
Giant sauropod dinosaurs evolved from smaller ancestors. New fossil discoveries show large, flexed-limbed sauropodomorphs lived alongside early columnar-limbed sauropods for 20 million years.
Area of Science:
- Paleontology
- Vertebrate Zoology
- Evolutionary Biology
Background:
- Sauropods, the largest terrestrial vertebrates, evolved from bipedal ancestors.
- Understanding the early evolution of sauropodomorphs is key to deciphering gigantism in dinosaurs.
Purpose of the Study:
- To investigate the early evolution and coexistence of different sauropodomorph body plans.
- To shed light on the tempo and mode of sauropod evolution.
Main Methods:
- Analysis of two new early sauropodomorph fossils from South Africa and Argentina.
- Comparative anatomical studies of limb morphology and inferred locomotion.
Main Results:
- Discovery of very large, flexed-limbed sauropodomorphs.
- Evidence suggests these forms coexisted with early, columnar-limbed sauropods.
- This coexistence persisted for approximately 20 million years.
Conclusions:
- Early sauropodomorph evolution was characterized by diverse body plans.
- Locomotory adaptations evolved independently or in parallel within early sauropodomorphs.
- The evolutionary trajectory towards gigantism in sauropods was not a simple, linear progression.
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