Bajadasaurus pronuspinax

Overview

Bajadasaurus, meaning "downhill lizard," was one of the weirdest-looking dinosaurs ever discovered! Living during the Early Cretaceous period, about 140 million years ago in what is now Argentina, this dinosaur had incredibly long, forward-curving spines on its neck that made it look like something from science fiction!

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Taxonomy & Classification

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

Bajadasaurus was related to Amargasaurus but had even more extreme spines!

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Physical Characteristics

Size & Build

• Length: About 9-10 meters (30-33 feet)
• Weight: Approximately 4,000 kg (4.4 tons)
• Height: About 2.5 meters at the hip
• Neck: Moderate length with EXTREME spines

The Incredible Spines

• Long, curved spines bent FORWARD over the head!
• Up to 60+ cm (2 feet) long each
• Ran down the neck and back
• Curved toward the front—unique among dinosaurs!
• May have been covered in keratin like horns

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What Were Those Crazy Spines For?

Scientists Have Ideas!

Theory	Explanation
Defense	Made it hard for predators to bite the neck
Display	Attracted mates or intimidated rivals
Species ID	Helped recognize other Bajadasaurus
Camouflage	Broke up body outline in vegetation

The forward curve suggests defense might be the answer!

The Porcupine Theory

• Spines curved toward attacking predators
• Like a giant porcupine's quills
• Would protect the vulnerable neck
• Predators would get stabbed trying to bite!

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Feeding & Diet

Low Browser

Bajadasaurus was built for ground-level feeding:

• Ate ferns, horsetails, and low plants
• Short neck meant feeding near ground
• Couldn't reach tall trees like other sauropods
• May have swept its head side to side
• Filled a specific ecological niche

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Discovery

A Recent Find

• Discovered in 2010 in Patagonia, Argentina
• Described and named in 2019
• Found in the Bajada Colorada Formation
• Name means "downhill lizard, forward spine"
• Only partial skull and neck bones found
• Caused worldwide excitement!

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Bajadasaurus vs. Amargasaurus

Spiny Cousins

Feature	Bajadasaurus	Amargasaurus
Spine direction	Forward-curving	Upward/backward
Spine length	Very long	Long
Age	140 million years	125 million years
Discovery	2019	1991

Bajadasaurus is the older, weirder cousin!

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Cretaceous Patagonia

Bajadasaurus's World

Lived alongside:

• Other unique South American dinosaurs
• Early predatory theropods
• Various crocodilians
• In river valleys and forests
• When South America was an island continent

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The Reconstruction Challenge

What Did It Really Look Like?

Scientists debate:

• Were spines covered in skin/sail?
• Or were they naked like horns?
• What color were they?
• Did they rattle or make sounds?
• We need more fossils to know for sure!

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Cool Facts

• Bajadasaurus had the most forward-pointing spines of any known dinosaur!
• Scientists think it looked like a "punk rock porcupine"
• Its name comes from the Bajada Colorada ("colorful downhill") region
• Only discovered in 2010 and named in 2019—very recent!
• Related to Amargasaurus, but 15 million years older
• May have lived alongside early tyrannosaur relatives
• The spines were probably brightly colored for display
• One of the most bizarre dinosaur discoveries of the decade!

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Bajadasaurus looked like something from another planet—a dinosaur with forward-pointing neck spines that made it one of the strangest-looking animals ever to walk the Earth!