Xenoposeidon proneneukos

Last updated: May 27, 2024
Verified by: AZ Animals Staff
© Levi bernardo, CC BY-SA 3.0 – License / Original

They may have acted as 'gardeners' to clear vegetation and disperse seeds through their feces.


Xenoposeidon Scientific Classification

Scientific Name
Xenoposeidon proneneukos

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Xenoposeidon Conservation Status

Xenoposeidon Locations

Xenoposeidon Locations

Xenoposeidon Facts

Fun Fact
They may have acted as 'gardeners' to clear vegetation and disperse seeds through their feces.
Biggest Threat
Climate change, evolutionary change
Tropical or sub-tropical forests
Spinosaurid dinosaurs
Favorite Food
Any kind of vegetation.
Ferns, cycads
Special Features
Long neck and tail.
United Kingdom
Number Of Species
United Kingdom

Xenoposeidon Physical Characteristics

Skin Type
Top Speed
10 mph
Several tons.
15-20 feet at the shoulder
30-50 feet

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“They may have acted as ‘gardeners’ to clear vegetation and disperse seeds through their feces.”

Xenoposeidon Facts

  1. Xenoposeidon is a genus of extinct sauropod dinosaur that lived during the Early Cretaceous Period, around 130 million years ago.
  2. The only known fossil specimen of xenoposeidon is a single neck vertebra that was discovered in the United Kingdom in 2002.
  3. The vertebra has small, circular openings on its surface that may have been for air sacs to help to lighten the skeleton while still being strong enough to supported the weight of the animal’s head and neck.
  4. The name “xenoposeidon” means “strange poseidon.” It was chosen by the paleontologists because of the unusual shape and openings in the neck vertebra.
  5. Sauropods like xenoposeidon are thought to have performed an important function in their environment by clearing vegetation from the forest floor to the treetops and dispersing seeds through their feces to grew new forests.

Xenoposeidon Scientific name

The scientific name of xenoposeidon is Xenoposeidon proneneukos.

The name “xenoposeidon” is derived from the Greek words “xenos,” meaning “strange,” and “Poseidon,” the Greek god of the sea. The paleontologists who described it chose the name because of the unusual shape of the neck vertebra. “Proneneukos” means “forward-leaning.” It refers to the orientation of xenoposeidon’s neck vertebra.

Xenoposeidon is classified as order Dinosauria and family Euhelopodidae. However, the taxonomy this dinosaur is still a matter of debate among paleontologists and more research is needed to fully understand its place in the evolutionary tree.

Description & Size

The only fossil of xenoposeidon discovered so far is a neck vertebra, so palentologists rely on comparisons to similar sauropod dinosaurs to conjecture about its size, appearance, and behavior. On this basis, it is likely that xenoposeidon had a body length of around 30-50 feet, a height of 15-20 feet at the shoulder and a weight of several tons. This is about the size of a semi-truck trailer you might see on a highway. By comparison, other species of sauropods reached sizes of up to 100 feet long and 100 tons in weight. This would make xenoposeidon a medium-sized sauropod

Sauropods like xenoposeidon had small heads, long necks, whip-like tails and stood on four legs as big as tree trunks to support their massive bodies. They were not built for speed and likely had a slow, plodding stride. They may have been able to walk around 5-10 miles per hour. This is comparable to the speed an average healthy human being today can reach as they move from jogging speed to a fast running speed. If you wanted to race with one, though, you shouldn’t be complacent. It’s possible sauropods could move much more quickly in short sprints, any may have literally thrown their weight around to throw threats off balance.

Xenoposeidon lived 130 million years ago.

©Slate Weasel / CC by 4.0 – Original / License

Xenoposeidon Evolution and History

The evolution and history of xenoposeidon is not well understood due to the limited fossil evidence that has been uncovered.

Based on the size and characteristics of the neck vertebra, xenoposeidon is thought to belong to the euhelopodid family of sauropod dinosaurs, which also includes euhelopus and barapasaurus. These large sauropods had distinctive neck vertebrae similar to those of xenoposeidon.

The euhelopodids are thought to have evolved during the Early Cretaceous Period, around 130 million years ago, and may have been closely related to other sauropod groups, such as the diplodocids and titanosaurs. However, the evolutionary relationships of Xenoposeidon and other euhelopodids are still the subject of debate among paleontologists.

Diet – What Did the Xenoposeidon Eat?

It is likely that Xenoposeidon, was a herbivore (plant eater). Sauropods are thought to have had a diet that consisted primarily of leaves, twigs, and other plant material, which they likely obtained by browsing on the foliage of trees and other plants. They may have also fed on ferns, cycads, and other low-lying vegetation.

Sauropods had strong jaw muscles and teeth adapted to grinding and crushing plant material. They had long necks that helped them reach high into the trees to feed on vegetation. At times they might even have stood up on their back legs, enabling them to reach even higher for tasty bits of tree-salad that other herbivores could not reach.

Habitat – When and Where Xenoposeidon lived

Xenoposeidon is thought to have lived during the Early Cretaceous Period, around 130 million years ago. This was a time when dinosaurs were the dominant land animals. A great deal of evolutionary change happened at this time and many new groups of dinosaurs emerged.

The climate at that time went through significant global warming, which expanded tropical ecosystems around the world. Xenoposeidon would have lived in a warm tropical or subtropical region with a great diversity of plants and animals. Some of the other dinosaurs likely to have shared its environment were the iguanodontids and ornithopods.

Sauropod dinosaurs, like xenoposeidon, are thought to have lived in a variety of habitats, including forests, grasslands, and wetlands. They may have lived in areas with a mix of vegetation, including trees, ferns, cycads, and other plant life.

Threats And Predators

Sauropods, in general, are thought to have been too large and well-defended to be hunted by most predators, and likely had few natural enemies. However, young, sick, or injured individuals certainly would have been in danger of predation. And because xenoposeidon was not the largest sauropod species, it may have been in greater danger than some of its bigger cousins. When unable to run away from danger, sauropods may have used their immense body weight as a defense by charging to barrel enemies over, and may have used their tails like powerful whips or clubs. it is also possible they could stand up on their back legs to appear even taller and more intimidating and to stomp with their massive front legs and feet.

The greatest potential predatory threat to xenoposeidon would have come from spinosaurid carnivores. Three species were discovered nearby that would have lived at the same time: Ceratosuchops inferodios and Riparovenator milnerae, and the baryonyx. Each of these would have been about 30 feet long, the size of a smaller xenoposeidon. They had mouths like crocodiles and were adapted to hunting in the water as well as on land.

Aside from predators, other major threats to xenoposeidon, as to all dinosaurs, may have come from climate change, disease, and loss of evolutionary advantages as new species evolved that were better adapted to take over their niche in the ecosystem.

Discoveries and Fossils – Where Xenoposeidon was Found

Fossils of xenoposeidon have only been found in one country: the United Kingdom. The only known specimen of xenoposeidon is a single neck vertebra discovered near the village of Swanage in Dorset County in the southern part of England. It was discovered by a team of paleontologists led by Dr. Phil Manning of the University of Manchester, who described the specimen and named the genus in 2007. It was identified as a new species based on its large size and the presence of a number of small, circular openings, or pneumatic foramina, on its surface. (See photo of the find here).

It was discovered in the Early Cretaceous-age Wessex Formation, which was deposited around 130 million years ago. The Wessex Formation is known for its rich fossil record, and has yielded a number of other important dinosaur fossils, including those of the sauropod dinosaurs barapasaurus, euhelopus, and pelorosaurus.

Something to keep in mind is that it is possible the fossil was not found in the original location where the animal lived. Because it is just one bone, it could have been transported to the place where it was found through processes of erosion and sedimentation. Researchers continue to look for more specimens to give a more accurate picture of this species and its original habitat.

Extinction – When Did Xenoposeidon Die Out?

Xenoposeidon is thought to have lived during the Early Cretaceous Period, around 130 million years ago. It disappeared at the end of the Cretaceous Period, around 66 million years ago in a mass extinction event known as the K-T extinction. The cause of this event is not fully understood, but it is thought to have been caused by a large asteroid impact that brought about global climate change. Some groups of dinosaurs, such as birds, survived and evolved into the diverse array of species that we see today.

Similar Animals to Xenoposeidon

  • Barapasaurus was a sauropod dinosaur that lived in what is today India during the Early Jurassic Period, which lasted from 201-171 million years ago.
  • Euhelopus was an Early Cretaceous sauropod dinosaur discovered in China. One of its distinctive features was that it had longer forelegs than hindlegs.
  • Supersaurus was a sauropod dinosaur that lived during the Late Jurassic Period, around 150 million years ago. It was one of the longest and heaviest sauropods known, and is known for its distinctive “super-lizard” skull

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About the Author

Drew Wood is a writer at A-Z Animals focusing on mammals, geography, and world cultures. Drew has worked in research and writing for over 20 years and holds a Masters in Foreign Affairs (1992) and a Doctorate in Religion (2009). A resident of Nebraska, Drew enjoys Brazilian jiu-jitsu, movies, and being an emotional support human to four dogs.

Xenoposeidon FAQs (Frequently Asked Questions) 

Was xenoposeidon a carnivore, herbivore, or omnivore?

Xenoposeidon was a sauropod dinosaur. This species was herbivorous, feeding on a variety of tropical and sub-tropical plant life. With its long neck, it was able to reach plants from the forest floor all the way up to the treetops.

When was xenoposeidon alive?

Xenoposeidon lived during the Early Cretaceous Period, around 130 million years ago.

How big was xenoposeidon?

The exact size of xenoposeidon is not known because of insufficient fossil evidence, but based on comparisons with other sauropods, it may have had a body length of around 30-50 feet and a weight of several tons. It may have been 15-20 feet tall at the shoulder.

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  1. Prehistoric Wildlife / Accessed December 29, 2022
  2. DinosaurPictures.org / Accessed December 29, 2022
  3. PeerJ / Accessed December 29, 2022
  4. Scientific American / Accessed December 29, 2022
  5. Activewild.com / Accessed December 30, 2022