Amargasaurus
A small sauropod with tall spines on its neck and back.
It is most notable for the two parallel rows of tall spines down its neck and back, taller than in any other known sauropod.
- Length
- 9 to 13 meters (30 to 43 feet)
- Weight
- Approximately 2.5–4 metric tons (2.8–4.4 short tons)
- Classification
- Sauropoda, family Dicraeosauridae
- Known for
- Two parallel rows of tall spines on neck and back
- Discovery location
- La Amarga Formation, Neuquén Province, Argentina
Lore & Background
The skeleton was found in sedimentary rocks of the La Amarga Formation in northern Patagonia, 70 kilometers south of Zapala. It is reasonably complete, including a partial skull, and is currently stored in the Bernardino Rivadavia Natural Sciences Museum in Buenos Aires.
Reader's Guide
Amargasaurus is significant as one of the best-known sauropods from the Early Cretaceous, providing valuable insight into the diversity of sauropod body plans. Its most distinctive feature—the two parallel rows of tall, bifurcated neural spines on the neck and back—has prompted several studies on their function. Hypotheses include that the spines supported a horn sheath, were connected by ligaments forming a neck sail, or were used for display, combat, or defense. As a member of the Dicraeosauridae, Amargasaurus had a shorter neck and smaller body size than many other sauropods, and it likely fed at mid-height, with a habitual snout position about 80 centimeters above the ground. The skeleton's completeness, including a rare sauropod skull, makes it a key reference for understanding dicraeosaurid anatomy and evolution.
Did You Know?
- Amargasaurus was small for a sauropod, measuring 9 to 13 meters in length and weighing about 2.5–4 metric tons.
- The tallest spines on its neck reached 60 centimeters on the 8th cervical vertebra.
- The species name Amargasaurus cazaui honors geologist Luis Cazau, who informed the team about the La Amarga Formation.
Frequently Asked Questions
Who is Amargasaurus?
Amargasaurus is a Late Cretaceous sauropod dinosaur from South America, classified within the family Dicraeosauridae. It is one of the better-documented members of that group and is widely recognized for its striking skeletal features.
What makes Amargasaurus's spines so special?
Two parallel rows of remarkably tall neural spines run along its neck and back, making them proportionally taller than those of any other known sauropod. Their exact biological purpose—whether for display, muscle attachment, or something else—is still debated among paleontologists.
How big was Amargasaurus?
The animal stretched roughly 9 to 13 meters (about 30 to 43 feet) in length and tipped the scales at around 2.5 to 4 metric tons. That places it in the smaller end of sauropod body sizes, well below giants like Argentinosaurus.
Where was Amargasaurus discovered?
Its fossils come from the La Amarga Formation in Neuquén Province, Argentina. That Patagonian region is famous for producing a rich assemblage of Late Cretaceous sauropod remains.
What family does Amargasaurus belong to?
It is placed in the family Dicraeosauridae within the order Sauropoda. This family is set apart from other sauropod lineages by a distinctive suite of vertebral and limb-bone characteristics.
More in Prehistoric Beasts 1-24
Elsewhere in the Prehistoric Beasts universe
Spotted an error? Know more?
This is a living reference — every entry is fact-audited, and reader corrections feed straight into our audit queue. Suggest an edit · See this site's audit record