Unique Spikes On The Back – Amargasaurus, Titanosaurs and Dicreaosaurids

Key Takeaways

• Titanosaurs, a subgroup of Sauropods, uniquely had bony spikes as part of their vertebrae.
• Fossils of Dicraeosaurids and Titanosaurs have been found across many continents.
• Amargasaurus is one of the most complete sauropod dinosaur remains ever found, with rare elements including a partial skull.
• The spines of Amargasaurus may have served various functions such as defense, species recognition, or thermoregulation.
• It thrived in braided river systems in ancient Argentina, coexisting with multiple sauropod species and grazing on low-growing vegetation.

Envision navigating the lush Cretaceous period in Argentina, where among the towering dinosaurs, one particularly unique sauropod, Amargasaurus, roamed with a neck so extensive it may never have seen its own feet. This distinctive dinosaur, armored with a dramatic double row of spines, is a wonder that intrigues me to no end.

What Was The Long Neck Dinosaur With Spikes On Its Back?

So, what exactly was Amargasaurus? Known for its elongated neck and distinctive spines, this dinosaur was a member of the sauropod family, which primarily consisted of large, herbivorous creatures. Despite its scary appearance, it likely led a peaceful existence, grazing on lower vegetation rather than reaching for the high tree tops canopy.

These giants lived during the Jurassic and Cretaceous periods of the Mesozoic Era. Carnivorous dinosaurs like T. Rex (North America) and Giganotosaurus (Argentina) are thought to have hunted these sauropods in their respective geographies. 

Amargasaurus, a distinctive sauropod dinosaur, featured a long neck. Existing in the Cretaceous Period, Amargasaurus walked the Earth around 125 million years ago. It exhibited prominent tall spines, possibly supporting a skin sail.

Standing on four legs, this dinosaur was adapted to a quadrupedal stance. It measured 30 feet in length, smaller in comparison to giants like Argentinosaurus. With a weight of approximately 3 tons, it was moderately sized.

The postulated skin sail on Amargasaurus, supported by its spines, may have served multiple functions. The spines might have been sheathed in keratin horns, though this remains unconfirmed by direct fossil evidence. Designed to eat low growing plants, Amargasaurus probably used its lengthy neck to access diverse food sources.

Air sacs within the respiratory system allowed efficient oxygen travel, a common trait in sauropods like Apatosaurus. While Amargasaurus shared some commonalities with Alamosaurus and Brachiosaurus, its spines were unique. Scientists continuously study these creatures, aiming to resolve the mysteries of their physiology and behavior.

Comparison with its sauropod relatives suggests Amargasaurus’s spines were not found in others like Brachiosaurus. Each dinosaur adapted uniquely to ensure survival. Ongoing research by scientists seeks to unravel details about Amargasaurus. These efforts bridge gaps in knowledge about these remarkable prehistoric creatures. Through careful analysis of fossils, we grow to understand the ecological niche that Amargasaurus occupied in its prime.

Keep on reading as I go deep into these unique and fascinating long-necked dinosaurs. You won’t want to miss it.

Discovering Amargasaurus

A well-preserved skeleton of Amargasaurus was unearthed in 1984 by José Bonaparte’s team in Argentina. This remarkable discovery included rare elements such as a partial skull, elevating it to one of the most complete sauropod dinosaur remains to date. The site of discovery, the La Amarga Formation, was indicative of the rich paleontological potential of the region.

Anatomy and Distinctive Spines

Within the skeletal structure of Amargasaurus, you’ll immediately notice the unique double row of tall, bifurcated spines extending from its neck to its back, a feature unmatched by its sauropod relatives. These elongated spines, reaching up to 60 centimeters, are the tallest among sauropods, suggesting a prominent visual display or other functional significance. The parallel rows of tall, upwardly projecting neural spines likely served multiple purposes, potentially including defense, species recognition, or thermoregulation.

Elongated spines: These were the tallest or longest spines and stuck out clearly from the neck. As mentioned, they were bone and fused as part of the vertebrae. They were visible in fossil specimens of Armargasaurus and Bajadasaurus. Some of the features of these spines were:

• a double row of neural spines down the neck
• thin and elongated (even sharp spikes)
• possibly covered by bony keratinous sheaths
• spines possibly connected by thin skin to create a sail
• dicraeosaurids were the only dinosaurs to have these types of spines

Bony spines (or distinctive spines)– These stood out and were clearly seen on the skeleton running in either one or two rows down the back of the sauropod, sometimes even along the tail. The shape was triangular or diamond-shaped (like the dorsal plates of the Stegosaurus). 

The Function of Spinal Structures

You may consider the possibility that Amargasaurus’ striking spinal structures served functions beyond mere physical support.

The conspicuousness of these spines could have been integral for display or intimidation, suggesting a complex behavioral repertoire.

Additionally, the hypothesis that these structures assisted in thermoregulation presents a fascinating avenue for further investigation, given their potential surface area and exposure.

Display or Intimidation

The Amargasaurus, known for its tall spinal structures, sparks debate over whether these features served for display or defense. The possibility of a double row of spines along its neck and back, potentially sheathed in skin to form a sail-like appearance, suggests they might have been used for visual signaling in social interactions or mate attraction.

Conversely, these intimidating spines could have served as a deterrent to predators, indicating a defensive role. However, this adaptation might have compromised neck mobility, highlighting a balance between the need for display or intimidation and functional movement.

Thermoregulation Possibility

As you consider the unique spines of Amargasaurus, it’s possible they played a key role in regulating the dinosaur’s body temperature. Now, delve into the scholarly aspects of this hypothesis:

1. Bifurcated Spines: The spines could be found bifurcated along their entire length, suggesting a design that could support a sail of skin.
2. Skin Sails: These sails, likely covered in a horny sheath, may have facilitated heat dissipation or absorption, crucial for a creature of such size.
3. Support Structure: The extremely tall spines on the neck and posterior half were supported by four robust vertebral processes, indicating a sturdy framework capable of thermal regulation.
4. Jurassic World Analogy: Imagine an Amargasaurus in Jurassic World, its skin sails catching the breeze, a majestic and efficient adaptation for survival in a diverse ecosystem.

Habitat and Paleoecology

Within the braided river systems of ancient Argentina, your long-necked Amargasaurus roamed, thriving among a variety of low-growing vegetation. This table highlights the key characteristics of Amargasaurus, their descriptions, and the significance of these features in its ecological niche and survival strategy.

Characteristic	Description	Ecological Significance
Habitat Adaptation	Lived in a habitat dominated by waterways, in a semi-arid climate with braided rivers	Indicates adaptation to the paleoecology of the region
Distinctive Features	Long tail and neck, small head, column-like legs, and unique back spikes	Each feature contributed to occupying a specific ecological niche
Spikes on Back	Unique to Amargasaurus, possibly used for defense or display	Contributed to survival strategy within its environment
Fossil Location	Found in the La Amarga Formation’s sandstones	Indicates the environmental conditions of its habitat
Diet and Feeding Behavior	Habitually fed at approximately 80 centimeters above ground	Reduced competition among large animals, allowed coexistence with other sauropods
Role in Ecosystem	Part of a complex dynamic with multiple sauropod species	Each species, including Amargasaurus, had a unique role in the ecosystem

Comparing Amargasaurus Size

You’ll notice that the Amargasaurus was modest in size when compared to its colossal sauropod cousins. Despite living approximately 129 to 122 million years ago during the Early Cretaceous, this dinosaur was small for a sauropod. To understand its stature, consider the following:

1. Length and Weight: Amargasaurus measured 9-10 meters in length and weighed approximately 2.6 metric tons, which is significantly less than some of the largest sauropods that could reach lengths of over 30 meters and weigh over 70 metric tons.
2. Neck Proportions: The neck of Amargasaurus, at 2.4 meters in length, was proportionally short, contrasting the typically elongated necks found in most other sauropods.
3. Spinal Structure: Its distinctive double row of neural spines, with the foremost dorsals being opisthocoelous, contributed to a unique silhouette not shared with its larger relatives.
4. Vertebral Fusion: The trunk of Amargasaurus was stabilized by nine dorsal and probably five fused sacral vertebrae, an anatomical feature highlighting its robust yet compact frame.

In the Field Guide to prehistoric life, Amargasaurus stands out not only for its size but also for its unique adaptations, providing a window into the diverse forms that sauropods could take.

Amargasaurus in Popular Culture

In recent years, Amargasaurus has captured your imagination through various media, from television to video games. This table summarizes the key aspects of Amargasaurus, its descriptions, and the impact it has had in various cultural and entertainment platforms.

Aspect	Description	Cultural Impact
Physical Characteristics	Long neck with distinctive spikes, peculiar dorsal vertebrae supporting elongated spines	Unique and easily recognizable in popular culture
Movement	Moves on four legs as a sauropod	Common depiction in various media
Television Appearance	Featured in ‘Dinosaur Train’ with a character named Martin	Introduces Amargasaurus to younger audiences
Video Game Appearances	Appears in ‘Fossil Fighters Frontier’ as a new vivosaur; featured in ‘Jurassic Park: Builder’ and ‘Dinosaur Hunting’	Captivates players with historical intrigue and distinctive anatomy
Influence in Pokémon Series	Inspired an evolution family including Amura and Aurorus	Demonstrates its impact on contemporary media and entertainment
Overall Cultural Significance	Integrated into various facets of entertainment	Highlights its lasting appeal and the creative freedom in reimagining this dinosaur

Natural History of Spiky Sauropods – Where They Lived and Common Anatomy

Now let’s turn our attention to the bigger picture and describe some of the species that Amargasaurus were related to within the sauropod classification. Two groups of sauropods that had spikes on their back, the dicraeosaurids and the titanosaurs. Dicreaeosaurids such as Amargasaurus and Bajadasaurus had long spikes that were part of their vertebrae, running down their necks and backs. These spikes are known as neural spines. Titanosaurs such as Alamosaurus and Argentinosaurus also had neural spines, but they were shaped like flat spiky plates and were on the neck, back, and tail. 

The dicraeosaurids were:

• Noted for having elongated spikes (neural spines) on the neck and flat triangle shaped spikes down its back
• Closely related to the diplodocidae clade, which included Diplodocus and Apatosaurus
• Had characteristically shorter necks and tails compared to other sauropods

The titanosaurs were:

• Known to have spikes (neural spines) along its back in flat triangle shaped spikes, although not all species had neural spines
• Many had osteoderms (bony deposits) individually as scales with hardened points giving the likeness of armor plating on their skin
• Claimed the title of being the biggest dinosaurs ever to have existed

Amargasaurus, a noted dinosaur of the Dicraeosauridae family, has distinct spikes sculpting its back. This spiked pattern aligns Amargasaurus to another spine-sailed dinosaur, Bajadasaurus from the same family. Titanosauria counterparts like Apatosaurus, Brachiosaurus, and Diplodocus, although from the same period, lack such distinctive spinal extravagance.

Interestingly, dicreaosaurids had pneumaticity, or presence of air sacs, in the presacral vertebrae of dicraeosaurids from Gondwana shows some variability, with Pilmatueia achieving the highest degree of pneumatization. (Source)

Titanosaurs were considerably larger, although not all of them reached the giant sizes of titanosaurs like Dreadnoughtus and Argentinosaurus. One of the traits they all had was osteoderms, a kind of bony scale that resembled armored skin. Not all titanosaurs had spikes on their back. 

Based on the size of the dinosaur compared to its small skull, both these clades of sauropods are regarded as being at the bottom of the EQ scale at an EQ of 0.2. For info about the intelligence of dinosaurs, check out my article Smartest Dinosaur Species – Hunters That Could Outsmart Its Prey.

As herbivorous dinosaurs, their teeth were flat and cone-shaped, designed for chewing and grinding vegetation. Some skull fossils of these sauropods show they had pencil-like teeth. 

Differences of Dicraeosaurids Compared to Other Sauropods Like Diplodocus and Brachiosaurus

Below is a comparison table between Sauropods, Titanosaurs, and Dicraeosaurs. These dinosaur groups share similar features but also have unique characteristics that distinguish them from each other.

Name	Similar Features	Unique Features
Sauropods	Quadrupedal stance, long necks and tails, large body size	Notable wide diversity, with some having armor-like skin and others having long spines.
Titanosaurs	Quadrupedal stance, long necks and tails, large body size	Generally more robust and often armored, with some species being the heaviest dinosaurs.
Dicraeosaurs	Quadrupedal stance, long necks and tails, large body size	Characterized by shorter necks and sharp, upward-pointing spines along the neck and back.

Remember that Titanosaurs are a subgroup of Sauropods, while Dicraeosaurs are a subgroup of Diplodocoids, another group within the Sauropodomorpha, the clade that encompasses all “sauropod-like” dinosaurs. Each of these groups possesses unique characteristics while sharing the common body plan of the Sauropodomorpha.

If you are interested in knowing more about where sauropods (more than 100 species) lived around the world, check out my article Where Did Long Neck Dinosaurs Live? A Global Snapshot.

Dicraeosaurs Species

Dicraeosaurus

The Dicraeosaurus, named for its “bifurcated” or “Y”-shaped neck vertebrae, featured thick spikes along its neck and back, distinguishing it from relatives like Diplodocus. Notably, it possessed a larger head compared to other dicraeosaurids. Several mostly complete skeletons of this species were discovered in Tanzania in 1914.

The Bajadasaurus

The Bajadasaurus, discovered by Pablo Gallina in 2010 in Patagonia, Argentina, is notable for its elongated neck spikes, similar to the Amargasaurus, with neural spines extending towards the skull rather than backward. These spines, measuring about 1 foot and 11 inches, possibly supported skin sails and were likely covered with a keratinous sheath or skin and horns, aiding in protection and thermoregulation. The partial skeleton found, including a skull with pencil-like teeth, offers a glimpse into this unique dinosaur’s appearance and physiology.

————————————————————————————————
Related Sauropod Articles You Might Also Be Interested In:
Sauropods Vs Prosauropods- The Surprising Differences in Sizes, Anatomy
Where Did Long Neck Dinosaurs Live? A Global Snapshot
What Are Long Neck Dinosaurs (Types, Size, List)?
————————————————————————————————

Titanosaurs

North American Titanosaur – Alamosaurus     

The Alamosaurus, a gigantic herbivore found in the southwestern US, is notable for its size, potentially the largest land dinosaur in North America, reaching up to 98 feet in length and weighing around 88 tons. Characterized by neural spines running down its back, neck, and tail, it also had osteoderms resembling armor. Uniquely, it is considered the only long-necked dinosaur to have coexisted in the same geographic region and time period as the T. Rex during the Late Cretaceous.

Amazingly, the only sauropod living with T. Rex was also a Titanosaur. If you are interested in reading more about the Alamosaurs and T. Rex, check out my article What Sauropods Lived with T. Rex? Plus, How They Coexisted.

Argentinosaurus Lived in Argentina 95 Million Years Ago    

The Argentinosaurus, a titanosaur discovered in 1987 in Argentina by Guillermo Heredia, is renowned for its immense size, estimated at around 90 tons and 115 feet in length, making it one of the most famous dinosaurs from Patagonia. Possessing neural spines and armored plates, it roamed river edges and open plains during the Late Cretaceous Period, about 95 million years ago. Initially considered the largest dinosaur upon its discovery and naming in 1993, it held this record for nearly a decade. The only known species in this genus is A. huinculensis, identified from tail vertebrae found in Huincul, Neuquén Province.

Chinese Titanosaur – Jiangshanosaurus     

The Jiangshanosaurus, a titanosaur discovered in Zhejiang province, China, is characterized by neural spines and evidence of osteoderm body armor scales, typical of Titanosauria. Although the projections from its spines are poorly preserved, the nearly complete fossil skeleton found, including a relatively small skull compared to its body size, confirms its classification as a titanosaur.

The Argentinian Titanosaur – Futalognkosaurus

The spikes of the Futalognkosaurus are located on the back, neck, and tail. The spines are approximately 3.9 inches long and are triangle-shaped. About 70% of the fossil skeleton was found, making it a rather complete fossil specimen. 

The unique characteristic of the Futalognkosaurus is that the neural spines were so large and ran almost the full length of its body. It weighed at least 33 tons, and its body length was 79 feet.

Frequently Asked Questions About Spiky Armored Sauropods