End date is still unknown, but a major change has been made to Pokémon GO. You'll now only find Fossil Pokémon in 7km eggs, not babies and other Pokémon.
In addition, Riolu is making his debut in the 10km eggs!
List of Fossil Pokémon available in 7km Eggs

Aerodactyl
Rock and Flying

Anorith
Rock and Bug

Archen
Rock and Flying

Cranidos
Rock

Kabuto
Rock and Water

Lileep
Rock and Grass

Omanyte
Rock and Water

Shieldon
Rock and Steel

Tirtouga
Water and Rock

It looks like Shadow Eggs will soon be available on Pokémon GO. Following the special 7km eggs recently included, these new little ones may just be linked to Team GO Rocket...