During what geologic period did the bony ray-finned fishes diversify tremendously and begin to dominate the aquatic habitats of Earth and when the lobe-finned fishes first appeared.

From the Silurain to Devonian period

Explanation:

Diversification of fish began during the Silurian period continued during the Devonian Period. The lobe-finned fishes first appeared during the Silurian.