Hint: The connecting link between amphibians and reptiles is an amphibian tetrapod that existed 280 to 270 million years ago in North America and Europe. It was a small creature that was 60 cm long in size.
An organism is said to be a connecting link when it has characters similar to both the biological species. The connecting link between amphibians and reptiles is Seymouria which was an animal living in the Permian period on both the land and in water. It is said to be a connecting link because its larval stages show amphibian-like features whereas its adult stages show reptile-like features. The young stages had external gills which were later lost due to metamorphosis. The adult stages had massive legs and carnivorous nutrition which lived in dry climates like reptiles.
Additional Information: Archaeopteryx: Also known as Urvogel, it is a genus of bird-like dinosaurs and it is believed that Archaeopteryx to be the transitional form of birds and dinosaurs.
Ichthyostega: It is a genus of four-limbed vertebrates that lived at the end of the Late Devonian Period.
Archaeornis: It is a genus of reptilian-like birds that had a long feathered tail, teeth in the jaws, and claws on the wings. It is related to Archaeopteryx.
So, the correct option is ‘Seymouria’.
Note: -Ichthyostega is not to be confused with Ichthyosaurs which were land reptiles that went back into the water to evolve as fish-like reptiles around 200 million years ago.
-The Permian is a geologic period that begins at the end of the Carboniferous period (300mya) up to the beginning of the Triassic period (250mya) and spans for 47 million years.
-The Devonian is a geologic period that starts from the end of the Silurian (400mya) period up to the beginning of the Carboniferous period (360 mya) and spans 60 million years.