Fun Trinacromerum Facts For Kids

Monika Sharma
Nov 28, 2022 By Monika Sharma
Originally Published on Sep 27, 2021
Edited by Katherine Cook
Fact-checked by Gowri Rao
Trinacromerum facts are about this dinosaur which had around four flaps.
Age: 3-18
Read time: 5.9 Min

The seas and oceans during the Lower Cretaceous time were ruled by plenty of marine reptiles, which are not generally considered to be dinosaurs. This extinct genus is often considered to have been sea reptiles rather than dinosaurs. One such marine reptile are the plesiosaurs from an extinct genus of sauropterygian sub-order. The exact temperature of water they lived in still needs to be researched.

When we jump further into the classification of this member from the polycotylid clade, there is a lot to learn from their fossil. There are plenty of sister species under the Plesiosauria clade, the Trinacromerum comes under the Sauropterygia family. The basics of the Plesiosauria family are Leptocleidia, Polyctylidae, the Trinacromerum comes in the third subcategory. They are also closely related to Dolichorhynchops. It has also been discovered that Trinacromerum euoplocephalus dinosaurs existed around 155 million years ago. Although a variety of specimens from Sauropterygia have contributed a lot towards the discovery of their behavioral traits, a lot about them can still be learnt by studying various replies around us today such as snakes and tortoises.

To learn more about such interesting creatures, make sure to check out our articles on Revueltosaurus and Ojoceratops.

Trinacromerum Interesting Facts

Was the Trinacromerum a dinosaur?

Close studies on the Trinacromerum skeleton reveal that this reptilia was very familiar with various dinosaurs of several other classifications but this reptile from Jurassic time is in reality an extinct genus of a marine reptile.

How do you pronounce 'Trinacromerum'?

It's very easy to pronounce this marine reptile from Kansas. The Trinacromerum lived during the Cretaceous period and Kansas is known to be the home of almost all genus families like polycotylid. To pronounce this dinosaur from Manitoba, just use this simple pronunciation 'Trina-cro-MERUM'.

What type of marine reptile was a Trinacromerum?

There is a group of names that this species of plesiosaurs have. This dinosaur is from the family Plesiosaurioda and it cousins with many other dinosaurs from the Jurassic period such as Dolichorhynchops and even other reptiles under Sauropterygia. This member of the polycotylid clan is a type of plesiosaur and is from the plesiosaurs family. Their discovered fossil reveals that they are an extinct genus and lived in places such as Kansas and Manitoba.

In which geological period did the Trinacromerum live?

Many plesiosaurs are the building blocks for modern-day sea reptiles. A lot of similarities can be seen in the current day reptilia which match with the Plesiosauria of the Jurassic and Cretaceous time. The Trinacromerum lived with other such family species such as Dolichorhynchops during the Late Cretaceous time. Their descendants were also found in the Jurassic period as well.

When did the Trinacromerum become extinct?

When studying various specimens that are members in the polycotylid clan, its has been found that the major reason for their extinction is same as that of other dinosaurs. Trinacromerum dinosaurs suffered extinction due to various environmental changes and the asteroid collision has a lot to do with this.

Where did a Trinacromerum live?

The Trinacromerum lived in places such as Kansas and Manitoba. Like other Plesiosauria dinosaurs from the polycotylid, this plesiosaur lived deep in the ocean and fed on small fishes, like its cousin species Dolichorhynchops from the Manitoba region.

What was a Trinacromerum's habitat?

The habitat type of this plesiosaur was determined after studying its fossil remains. The classification of Trinacromerum dinosaurs has a lot to do with their habitat conditions. Most plesiosaurs from the polycotylid kingdom lived in the oceans. The Trinacromerum size was very large so this dinosaur would have been very easy to recognize during those times if they were found swimming on the surface. To avoid larger land predators, the Trinacromerum mostly remained down the shore, swimming in the deep ocean.

Who did a Trinacromerum live with?

These specimens from Kansas lived with a bunch of dinosaurs and other Trinacromerum dinosaurs as well. Their fossil classification talks a lot about their impact on current-day sea reptiles that we see. For now, we can say that it's possible that Trinacromerum dinosaurs lived with other dinosaurs or even members of the same family. The current-day water snake and plain-bellied water snake are good examples of the descendants of Trinacromerum.

How long did a Trinacromerum live?

We can say that this Trinacromerum from Kansas lived for around 15-18 years in the water bodies of Kansas during the Late Cretaceous time.

How did they reproduce?

The reproduction in Trinacromerum dinosaurs is confused. It is not known if they were egg-laying dinosaurs or if they gave direct birth to the young. As the weight of this Plesiosauria is very huge, they would not have been able to go to the surface and lay eggs. Scientists have theorized that Trinacromerum dinosaurs gave direct birth to their young.

Trinacromerum Fun Facts

What did a Trinacromerum look like?

The Trinacromerum from Kansas has four long flaps and a long snout, like other plesiosaur reptiles. Their fossil also shows their long snout which is similar to most Plesiosauria.

This marine reptile had a long snout and they often ate small fishes.

How many bones did Trinacromerum have?

The exact number of bones that a Trinacromerum had is not yet known because as their complete fossil has not yet been discovered.

How did they communicate?

Communication among Trinacromerum dinosaurs from the Cretaceous time was either through their flaps or by producing long and loud vocal calls which can be seen in modern whales. It was very important for this reptile from Kansas to communicate with other family members as during the Cretaceous time, the Trinacromerum was an easy target for large land predators.

How big was a Trinacromerum?

A Trinacromerum was around 9.8 ft (3 m) in size. The Trinacromerum may not have been the largest sea reptile of the Cretaceous time but they were still pretty big in size. They were around five times smaller than a current-day whale shark and around a good seven to eight times smaller than a fully mature bowhead whale.

How fast could a Trinacromerum move?

The four flaps of Trinacromerum dinosaurs were useful while swimming in deeper waters or just swimming near the surface of the sea. We can determine that Trinacromerums were good swimmers.

How much did a Trinacromerum weigh?

A Trinacromerum could have weighed anywhere around 200 lb (90.7 kg).

What were the male and female names of the species?

Both the females and males of this species share the same name. They were almost the same in regard to their features. Also, the behavioral traits of both sexes are considered to be the same, meaning they both share the same name.

What would you call a baby Trinacromerum?

The babies of dinosaurs and reptiles share the same name. Like a baby, the reptile is called either a hatchling or a nestling. The same way a baby Trinacromerum is also called a nestling or a hatchling.

What did they eat?

The Trinacromerum could not catch larger prey as they were very small in size themselves. They mostly survived on smaller fishes or other small sea creatures.

How aggressive were they?

Trinacromerums are not considered to have been very aggressive.

Did you know...

It is believed that the Trinacromerum may have been the same size as a dolphin or it just shares some behavioral traits with them.

How many species did the Trinacromerum have?

There are two species, T. bentonianum, and T.kirki.

What does Trinacromerum mean?

The name 'Trinacromerum' means 'three tipped femur'.

Here at Kidadl, we have carefully created lots of interesting family-friendly prehistoric animal facts for everyone to discover! Learn more about some other creatures from our Libonectes facts and Silesaurus facts for kids.

You can even occupy yourself at home by coloring in one of our free printable swimming Trinacromerum coloring pages.

Main image by Nobu Tamura

Second image by Saku Takakusaki

Trinacromerum Facts

What Did They Prey On?

Small fishes

what Type of Animal were they?


Average Litter Size?


What Did They Look Like?

Gray and white

How Much Did They Weigh?

200 lb (90.7 kg)

Skin Type

Soft scales

How Long Were They?

9.8 ft (3 m)

How Tall Were They?










Scientific Name

Trinacromerum bentonianum

What Were Their Main Threats?

Natural disasters

What Habitat Did They Live In?


Where Did They Live?

Kansas and Manitoba
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Written by Monika Sharma

Bachelor of Science specializing in Electronics and Telecommunication

Monika Sharma picture

Monika SharmaBachelor of Science specializing in Electronics and Telecommunication

With a passion for crafting engaging and informative content, Monika brings a wealth of writing experience to our team. Her Bachelors in Electronics and Telecommunications from Symbiosis Institute Of Technology adds a unique perspective to her work, allowing her to effectively communicate complex ideas in a clear and concise manner. Over the past two years, Monika has perfected her writing skills through her roles as a content writer, content manager, and digital marketer for reputable companies in both the USA and India. This hands-on experience has provided her with a deep understanding of industry trends and best practices, ensuring that the content she produces is always of the highest quality. She stays current with the latest field developments,continuously refining her skills to deliver exceptional content.

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