Indeed, the mosaics are very beautiful, although those depicted in the linked article had already been discovered more than a year ago. Therefore, either the author is somewhat of a slowpoke or he didn't have access to any updated material, so he was forced to use photos of the already discovered ones to enrich his article. Still, they are great mosaics and as you correctly assumed, Roma, the first mosaic concerns the Nine Muses of the Greek mythology.
Calliope, the Muse of epic poetry is located in the center of the circle, while Melpomene, the Muse of singing and tragedy is found between Thaleia and Terpsichore, the Muse of dancing. On the other side, we can see Euterpe, the Muse of music, between Thaleia and Clio, the Muse of history. Next to Clio is Urania, the Muse of astronomy, next to whom, Polyhymnia, the Muse of sacred poetry is found. Finally, Erato, the Muse of lyric poetry is located between Polyhymnia and Terpsichore.
The second mosaic depicts Oceanus, the god of... oceans, surprisingly and his daughter, Tethys, also an aquatic goddess.