Check under Maidenhair Fern to see if that's what it looked like in the "before" stage. Bit hard to tell now. There are some Maidenhairs with large leaflets. Not sure of their exact names but they might go under something like 'Giant Maidenhair'.

If it was healthier before in the same pot and soil then the problem could be not enough water, too hot an environment, and/or too much direct sun. They shouldn't dry out.

Agree probably something like Adiantum peruvianum.
Don't rule out too much water, either. They like moist well-drained soil and humidity. They don't like sitting in water so if that arrangement has no drainage that might be the problem.
If it was dry or dry air, then misting and increased water would help. If the stems don't recover then cut them off and hope that the plant will produce new fronds when it has the right conditions.