Thanks to Joel Kennedy, I've been learning the original melody (tricky!) to Moondog's amazing canon "Nero's Expedition". I had long wondered about the Sud of Nubia. I suspected Moondog of erudition rather than fantasy here. Being in a time-wasting mood today, I did some searching around and found this from a scanned-in-as-image report of the Crocodile Specialist Group Steering Committee Minutes, 1993, Darwin, Australia (the rather attractive crocodile drawing is from the report):
Proposal for a Crocodile Survey in the Sudan
This proposal had also been approved by the CITES Standing Committee. Dietrich Jelden suggested that the proposal was generally acceptable but some practical considerations might require changes in implementation. Social unrest and warfare in some parts of the country made some of the proposed survey locations (e.g. the Sud of Nubia) impractically dangerous at present.
Update: somewhat disappointingly, it turns out that if you spell it "Sudd" you get a lot more information, including the inevitable Wikipedia:
Less disappointingly, I suspect someone of perpetrating a sly tribute on the Wikipedia page for Nero: