Question

________ represents the connecting link between amphibians and reptiles.
A. Seymouria
B. Archaeopteryx
C. Ichthyostega
D. Archaeornis

Answer 1

Hint: Connecting links are those extinct organisms which are in intermediate or transitional state between two biological species during evolution.

Complete answer:
Seymouria are extinct creatures from the Early Permian of North America and Europe, about 255 million to 299 million years old. They were basically amphibian tetrapods, well adapted to life on land but had many features of reptiles. That’s why ‘option a’ is correct.
Archaeopteryx lived during the Late Jurassic Epoch, about 150 million years ago which is now Bavaria, southern Germany. They were considered a transitional form between dinosaurs and modern birds. That’s why ‘option b’ is incorrect.
Ichthyostega are extinct animals that lived during the late Devonian Period, about 370 million years ago. It shows the evolutionary link between pisces and reptiles. That’s why ‘option c’ is incorrect.
Archaeornis is one of the oldest fossil birds found during the Jurassic period. Earlier it came under the genus Archaeornis but now it has been placed under Archaeopteryx. It had teeth in the jaws, claws on the wings and a long feathered tail.

Hence, the correct answer is option (D).

Additional information:
Primarily, still now two species have been found: Seymouria baylorensis and Seymouria sanjuanensis. The fossils of S. baylorensis are still now only found in Texas, USA whereas S. sanjuanensis are more abundant and widespread. The adults are primarily terrestrial but at early life stages they lived in water.

Note:

Seymouria	Between amphibians and reptiles.
Archaeopteryx	Between dinosaurs and modern birds
Ichthyostega	Between pisces and reptiles
Archaeornis	Earlier placed under Archaeornis, later believed to be Archaeopteryx