Mystery fern appeared in compost heap – ID?

Last year a compost bin had an unfortunate encounter with a plumber, my husband, and a bobcat. The compost bin did not survive. The remains have been in a sad pile for months.

I finally decided it was time to give the wreckage a proper burial and discovered this fern growing in it. I've potted it up in the compost it was enjoying so much, but have no idea what sort it is, or its requirements, aside from neglect and abandonment.