Fun Ichthyostega Facts For Kids

Ichtyostega was a tetrapod that lived about 370 million years ago during the Late Devonian period and was the first known tetrapod from that time. The discovery of this fish-like tetrapod was made in the period of the 1930s in East Greenland and was described by Gunner Säve-Söderbergh in 1932. Often referred to as the 'first four-legged fish', paleontologists believe that they displayed a mix of fish and amphibian behavior as well as features. This further contributed to the theory that these tetrapods would have lived both in water and on land but spending a more significant amount of time underwater. What further grounded this theory is that it was pretty heavy and its legs were not strong enough to carry its stout body around. When they were on land, they would have probably dragged themselves, moving about at a slow pace! Two scientists, Ahlberg and Clack have speculated that the Ichthyostega had a particular terrestrial movement that was very similar to the modern-day seals. The legs of the aquatic Icthyostega didn’t have the range of motion that was necessary for walking straight up from the ground. Ichthyostega had lungs and limbs that helped it navigate through shallow water in swamps and swiftly move onto land as well. The pretty large ribcage of this earliest known amphibian was constructed of ribs that overlapped and these early evolutionary creatures had a strong skeleton structure, a spine that was rigid, and forelimbs that were powerful enough to pull their body out of the water. It also had a fish-like tail and gills with an amphibian skull and hind limbs. The hind limbs in the body of these aquatic early tetrapods were smaller in size in comparison to the forelimbs and probably functioned more like paddles than legs. The tail of this late Devonian tetrapod animal had a small size dorsal fin towards the end and the bony structures on it are similar to that identified in modern fishes. The Ichthyostega diet consisted of fish that it would have caught while swimming around easily and comfortably in the water. They would have also consumed small lizards when they hunted and moved on land. Many types of research and studies suggest that there are many commonalities between Ichthyostega and many water vertebrates that lived earlier or in the same time as Ichthyostega including a small region of the snout, gill covering in fish, the appearance of a bone in the cheek region, and their body scales were quite short. It sort of looks like a cross between a fat iguana and an alligator. You can find a complete skeleton of this early animal at the American Museum of Natural History in New York!

If you'd like to learn more about dinosaurs, check out our Homalocephale fun facts for kids or Ludodactylus interesting facts that are sure to keep you hooked!

How do you pronounce 'Ichthyostega'?

'Ich-thy-ostega' is the Ichthyostega pronunciation. Since 1929 and in 1932, a large number of fossils and other specimens of Ichthyostega have been identified from the Upper Famennian fossils of the eastern Greenland region. The famous paleontologist Gunnar Säve-Söderberg went on to conclude that at least three species of Ichthyostega were known to have existed! The reconstruction of the aquatic Ichthyostega fossil remains indicated that they could have been at the beginning of the evolutionary line, being the first tetrapods to have walked on land.

What type of dinosaur was an Ichthyostega?

Ichthyostega is an early tetrapod genus about 370 million years ago that lived at the end of the Upper Devonian period. The genus is closely related to Acanthostega gunnari which was also found in the same location as the Ichthyostega. These earliest known tetrapods were fish-like animals that made both land and water their habitat. However, they spent most of their time underwater.

In what geological period did the Ichthyostega roam the Earth?

These four-legged land vertebrates were found as fossils in the rocks of Eastern Greenland and roamed the earth during the Upper or late Devonian period.

When did the Ichthyostega become extinct?

This Late Devonian tetrapod became extinct about 70 million years ago. Slightly related to amphibians and having primitive fish-like features, they were the earliest known tetrapods.

Where did an Ichthyostega live?

Ichthyostega was a semi-aquatic animal. This meant that it spent its life both on land and water. Having a stout body with short hind limbs, these species were mostly underwater for long periods of time and only came onto land for food and sometimes, habitat.

What was an Ichthyostega's habitat?

The habitat of these well-developed tetrapods was found to be both land and water. Even though these species spent most of their time in the water, their time on land was very restricted. This could be due to the inability to walk with ease on land since their limbs only made it easy to move in the water. A reconstruction of this animal like the ribs and

Who did an Ichthyostega live with?

With research and studies conducted throughout history, these species, similar to the Acanthostega, were believed to have lived a solitary life. They crawled slowly from water onto the shores, but were very swift in water, given their body structure.

How long did an Ichthyostega live?

The tetrapod Ichthyostega, whose fossils were found in eastern Greenland, lived for a good amount of time, although the exact number of years is not known. They were the earliest known tetrapods to have been found by scientists and paleontologists.

How did they reproduce?

Reproduction among these four-legged vertebrates was easy and simple. Like most fish, these tetrapods laid eggs in water and their fertilization took place externally in water too! These eggs then became aquatic larvae. This primitive mode of reproduction has been inherited by most modern amphibians.

What did an Ichthyostega look like?

The basic morphology of these animals is very similar to modern-day tetrapods. Ichthyostega stood as a transitional fossil between fish and tetrapods, fusing the gills and tails of a fish with amphibian skulls and limbs. The limbs and the lungs helped the Ichthyostega to navigate through the water. The head of this tetrapod is similar to that of a frog. The skull had fish-like features too! They had a dorsal fin on the tail and they were also believed to have tall neural spines in the pelvic region. The spine of these early vertebrates was well-developed and strong. The limbs were slightly larger than its modern relatives and the hind limb had seven digits. Their fins would have been used for efficient locomotion and steer themselves in the right direction. The digits on the forelimbs are yet to be discovered. The body of these animals was stout and rounded which would be the reason why they were slow on land but quick in the water. The distance between their hind legs and their forelimbs would have also added to their slowness in movement. Recently, the easier access to existing specimens has allowed Ahlberg and Clack to make new interpretations of the Ichthyostega.

How many bones did an Ichthyostega have?

Very little information exists on how many bones these animals had. Although enough parts of their skeleton were found to draw conclusions about their lifestyle, the forelimbs were still missing. However, these tetrapods would have definitely had over 150 bones! The series of bony structures found in its tail is also seen in the tail anatomy of fishes.

How did they communicate?

Just like amphibians, these tetrapods also shared similar communication patterns with them called acoustic communication. They are long-distance signals that are used for protecting their territories, make new ones, and to also attract their mates.

How big was an Ichthyostega?

Ichthyostega size was fairly large and this animal was broadly built. Being about 60 in (152.4 cm) in length, about the same as a Californian kingsnake.

How fast could an Ichthyostega move?

These animals were quite slow on land, dragging themselves along the way. But, once they got into the water they were deft and swift in movement. Their easy locomotion in water could have been due to the shape of the bodies they possessed and their webbed feet, which would have proved to be an advantage in easily moving in the shallow water. By studying the Ichthyostega fossils in great detail, scientists suggest that their advanced forms put them on the evolutionary line to being the first tetrapods to have moved on land.

How much did an Ichthyostega weigh?

Ichthyostega weighed about 50 lb (22.6 kg).

What were the male and female names of the species?

These early tetrapods did not have any specific male or female names. They are known by their common name which is Ichthyostega.

What would you call a baby Ichthyostega?

It is currently not known what a baby Ichthostega is called as but since these animals lay their eggs in water, the babies can be called larvae.

What did they eat?

The Ichthyostega diet consisted of lizards when it was onshore and small types of fish when in water. They had both lungs and gills but relied on their gills often, and so fish probably made up the largest portion of their diets.

How aggressive were they?

It is not known to what degree these animals were aggressive. Since they lived solitary lives and were by themselves for the most part of it, aggression was not really a major attribute in the behavior of these amphibian-like vertebrates. The Ichthyostega nature was not wild either!

Did you know...

The first creature believed to have walked on land is known as Ichthyostega. They lived in the Devonian period and were believed to have lived under constant fear of dinosaurs. The Devonian period is also known as the 'age of fishes'.

Why did Ichthyostega go extinct?

These early vertebrates, whose fossil remains were named by Gunnar Säve-Söderbergh in 1932, were suspected to have gone extinct around 80 million years ago. They went extinct due to reasons like volcanic eruptions, earthquakes that would have destroyed their habitat, and also due to the fact that they were mainly preyed on by other large sea animals.

What did the Ichthyostega evolve from?

This Devonian tetrapod, Ichthyostega evolved from amphibians. Ichthyostega and Acanthostega are closely related and the latter is also from East Greenland. Ichthyostega's skull seems more fish-like than that of Acanthostega. Specifically, it possessed lungs and limbs, which allowed it to move efficiently through shallow water. Their great resemblance to sea specimens such as their similar ribs, spine structure, and other parts or regions of the skeleton truly justify this.

Here at Kidadl, we have carefully created lots of interesting family-friendly dinosaur facts for everyone to discover! Learn more about some other creatures from our Ichthyovenator interesting facts, or Yinlong fun facts for kids.

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

Main image by Matteo De Stefano/MUSE.