Amargasaurus cazaui

Overview

Amargasaurus, meaning "La Amarga lizard," was one of the most bizarre-looking sauropods ever discovered! Living during the Early Cretaceous period, about 129-122 million years ago in what is now Argentina, this dinosaur sported an incredible double row of tall spines running down its neck and back—making it look like no other dinosaur on Earth!

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Taxonomy & Classification

• Clade: Sauropoda
• Family: Dicraeosauridae
• Diet: Herbivorous
• Locomotion: Quadrupedal

Amargasaurus was part of a unique family of short-necked, spiny sauropods found only in South America!

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Physical Characteristics

Size & Build

• Length: About 9-10 meters (30-33 feet)
• Weight: 2,000-4,000 kg (2-4 tons)
• Height: About 2.5 meters at the hip
• Neck: Relatively short for a sauropod

Small compared to giant sauropods—but those spines made it unforgettable!

The Amazing Spines

• Two parallel rows of tall neural spines
• Ran from neck to mid-back
• Some spines were up to 65 cm (2 feet) tall!
• May have supported skin sails or stood alone
• Possibly used for display or defense

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What Were the Spines For?

Scientists Debate!

Several theories exist:

Theory	Purpose
Sail/Display	Attract mates, intimidate rivals
Thermoregulation	Heat up or cool down
Species recognition	Identify each other
Defense	Make it look bigger to predators
Fat storage	Like a camel's hump

The most popular idea: display and communication!

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Spines: Sail or Naked?

Two Possibilities

Sail Theory:

• Skin stretched between the spines
• Like a double sail down the neck
• Could change color for display
• Would help with temperature control

Naked Spines Theory:

• Spines stood alone like horns
• Covered in keratin (like horns)
• Could make clacking sounds
• More dramatic appearance!

We don't know for certain which is correct!

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Feeding & Diet

Low Browser

Unlike tall-necked sauropods:

• Fed on low-growing plants
• Ate ferns, horsetails, and cycads
• Short neck meant ground-level feeding
• May have used neck to sweep side to side
• Filled a different ecological niche than taller relatives

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Discovery

Found in Patagonia

• Discovered in 1984 in Argentina
• Found in the La Amarga Formation (gives it its name!)
• Described by Leonardo Salgado and José Bonaparte
• One nearly complete skeleton found
• One of the best-known South American sauropods

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Cretaceous South America

Amargasaurus's World

Lived alongside:

• Other sauropods with different feeding heights
• Early abelisaurid predators
• Crocodilians in rivers
• In a warm, semi-arid environment
• When South America was isolated from other continents

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The Dicraeosauridae Family

Unique South American Sauropods

Amargasaurus was part of a special group:

• All had shortened necks
• All had tall neural spines
• Only found in Gondwana (southern continents)
• Evolved differently from northern sauropods
• Represent unique evolutionary experiments

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Cool Facts

• Amargasaurus had the longest neural spines of any sauropod!
• Its neck spines were forked—two rows side by side
• Despite being a sauropod, its neck was relatively short
• Named after the La Amarga Canyon in Argentina
• The spines may have made sounds when struck together
• Only one good skeleton has been found
• Would have looked truly alien compared to other dinosaurs
• A popular dinosaur in video games and toys because of its unique look

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Amargasaurus was nature's punk rocker—a sauropod that traded the standard long neck for an incredible double mohawk of spines that made it one of the most distinctive dinosaurs ever!