RESEARCH STARTER
Ichthyostega
Ichthyostega is considered one of the earliest known amphibians, notable for its ability to inhabit both aquatic and terrestrial environments. Growing to about three feet long and weighing over 200 pounds, this prehistoric creature resembled modern-day crocodiles in some aspects. Ichthyostega possessed strong front legs that supported its weight on land, while its flipper-like back legs and robust tail facilitated movement in water. Its eyes were positioned high on its head, allowing it to see while floating in murky waters, and it had specialized openings that functioned as snorkels to aid in breathing when submerged.
Ichthyostega primarily fed on small fish, amphibians, and invertebrates, preying on creatures it could swallow whole due to its size. However, it faced threats from larger predators, such as Eurypterids, both in aquatic and terrestrial contexts. While little is known about its reproductive habits—no fossils of young Ichthyostega have been discovered—it is believed that like many amphibians, it likely laid eggs in water. This amphibian thrived in a moist, subtropical climate, with fossil evidence found primarily in Greenland. Overall, Ichthyostega serves as a significant example of early vertebrate evolution, bridging the gap between life in water and on land.
Published In: 2020 1 of 1
Full Article
Animals in the genus Ichthyostega lived in the Devonian Period and were the first aquatic animals to have lived also on land. It resembled modern-day crocodiles. Its name Ichthyostega means “fish roof.”
Kingdom: Animalia
Phylum: Chordata
Class: Amphibia
Order: Ichthyostegalia
Family: Ichthyostegidae
Genus: Ichthyostega
Species: Various (see below)
Ichthyostega includes Ichthyostega eigili and Ichthyostega watsoni, though some scientists consider these to be one species. The classification of these animals has been long debated. Ichthyostega stensioei was the first species of this genus to be discovered. It was not a large animal. It only grew to 5 feet (1 1/2 meters) long and weighed around 50 pounds (22 1/2 kilograms). With strong front legs that carried much of the animal's weight, Ichthyostega crawled slowly. In the water, the animal used its flipper-like back legs and strong tail to move. The animal could feel small vibrations in the water through special nerves in the animal's head. This helped it see better in its dark and cloudy surroundings. Its eyes were high on its head, like crocodiles. This allowed the animal to see as it floated at the surface of a cloudy swamp. At the back of Ichthyostega's head were two small openings connected to the animal's throat. These openings acted as snorkels and helped the animal breathe as it swam. The animal had special nostrils which helped it smell underwater, like fish.
Ichthyostega lived on a diet of fish, amphibians, and invertebrates (animals with no backbone). Ichthyostega, like crocodiles, preyed on animals on land and in the water. Because of its small size, it probably only attacked animals it could swallow in one bite. Some fish that swam with Ichthyostega had thick, armored skin and may have been too difficult to eat. It had better luck preying on smaller fish, fish larvae (eggs), worms, and insects.
Many of the larger fish, like the freshwater shark, would have had an easy time preying on the small Ichthyostega. It was also in danger of being attacked by Eurypterids. These large, crab-like predators threatened Ichthyostega in water and on land. They could grow to seven feet long and had long, strong legs which they used to cut up their prey.
Scientists are unsure about the breeding habits of Ichthyostega because no fossils of the young have been found. Most female amphibians lay unfertilized eggs in water, where a male fertilizes them. The eggs then hatch from larvae, or small egg-like creatures. When born, young Ichthyostega had no gills for breathing in water.
Ichthyostega lived in a moist, subtropical climate near the rivers and coastal areas. This gave Ichthyostega plenty of insects to eat and attracted other small amphibians.
Fossil remains of Ichthyostega have been found in Greenland.
Bibliography
"Ichthyostega." A-Z Animals, 2 Nov. 2022, a-z-animals.com/animals/ichthyostega. Accessed 1 May 2024.
Mosher, Dave. "Evolutionary Flop: Early 4-Footed Land Animal Was No Walker?" National Geographic, www.nationalgeographic.com/animals/article/120523-tetrapod-walk-flopped-nature-science-ichthyostega. Accessed 1 May 2024.
Full Article
Animals in the genus Ichthyostega lived in the Devonian Period and were the first aquatic animals to have lived also on land. It resembled modern-day crocodiles. Its name Ichthyostega means “fish roof.”
Kingdom: Animalia
Phylum: Chordata
Class: Amphibia
Order: Ichthyostegalia
Family: Ichthyostegidae
Genus: Ichthyostega
Species: Various (see below)
Ichthyostega includes Ichthyostega eigili and Ichthyostega watsoni, though some scientists consider these to be one species. The classification of these animals has been long debated. Ichthyostega stensioei was the first species of this genus to be discovered. It was not a large animal. It only grew to 5 feet (1 1/2 meters) long and weighed around 50 pounds (22 1/2 kilograms). With strong front legs that carried much of the animal's weight, Ichthyostega crawled slowly. In the water, the animal used its flipper-like back legs and strong tail to move. The animal could feel small vibrations in the water through special nerves in the animal's head. This helped it see better in its dark and cloudy surroundings. Its eyes were high on its head, like crocodiles. This allowed the animal to see as it floated at the surface of a cloudy swamp. At the back of Ichthyostega's head were two small openings connected to the animal's throat. These openings acted as snorkels and helped the animal breathe as it swam. The animal had special nostrils which helped it smell underwater, like fish.
Ichthyostega lived on a diet of fish, amphibians, and invertebrates (animals with no backbone). Ichthyostega, like crocodiles, preyed on animals on land and in the water. Because of its small size, it probably only attacked animals it could swallow in one bite. Some fish that swam with Ichthyostega had thick, armored skin and may have been too difficult to eat. It had better luck preying on smaller fish, fish larvae (eggs), worms, and insects.
Many of the larger fish, like the freshwater shark, would have had an easy time preying on the small Ichthyostega. It was also in danger of being attacked by Eurypterids. These large, crab-like predators threatened Ichthyostega in water and on land. They could grow to seven feet long and had long, strong legs which they used to cut up their prey.
Scientists are unsure about the breeding habits of Ichthyostega because no fossils of the young have been found. Most female amphibians lay unfertilized eggs in water, where a male fertilizes them. The eggs then hatch from larvae, or small egg-like creatures. When born, young Ichthyostega had no gills for breathing in water.
Ichthyostega lived in a moist, subtropical climate near the rivers and coastal areas. This gave Ichthyostega plenty of insects to eat and attracted other small amphibians.
Fossil remains of Ichthyostega have been found in Greenland.
Bibliography
"Ichthyostega." A-Z Animals, 2 Nov. 2022, a-z-animals.com/animals/ichthyostega. Accessed 1 May 2024.
Mosher, Dave. "Evolutionary Flop: Early 4-Footed Land Animal Was No Walker?" National Geographic, www.nationalgeographic.com/animals/article/120523-tetrapod-walk-flopped-nature-science-ichthyostega. Accessed 1 May 2024.