Its great to see good discussion develop despite distractions, and some excellent observations have been made by Iain. It is quite true that a weapon such as this does seem quite of of context among the typical Nilotic forms, particularly of course the kaskara. It is further concerning when looking at the zoomorphic motif which I have noted as a crocodile, while clearly there are similar images much more stylized seen from motif from regions to the west such as the scabbard shown.
The pierced image on the sword Brian has posted seems to me much more like a crocodile, note the head shape, the tail and especially the cross hatch design on the back, presumably scales. The waran lizard, whose hides are also used, seems far less totemic than the crocodile, who has a long history of being a much feared and revered icon into ancient times in these regions.
While my reference to this type sword being from Dongola came from recollection from an important group of Sudanese arms on tour in 2002, with one of these with daggers and kaskara etc, I have now found one of the original references per Iains request.
In the 1896 revision of Lord Egertons "Indian and Oriental Arms and Armour" (Dover Press, 2002), #197, which is virtually identical to this example of Brians, and described as an Arab sword made in Dongola and used in the Sudan. It is described in the text on page 157 as having a hilt of ebony and ivory with pommel in crescent shape, the image of a crocodile in the blade. The geometrics on the blade vary from Brians, but the crocodile shape is the same as seen on other examples.
This is an interesting revision of Egertons first issue of this reference from 1880 on mostly Indian arms, now including the Sudan, clearly after the campaigns recently taking place, and precluding Omdurman in 1898.
These swords are seen in line drawing form in "Weapons: The Diagram Group", Ed. David Harding, p.36, #9, described as Arab sword from Dongola with crocodile in blade. In reviewing the bibliography there is no mention of Egerton though the list seems quite comprehensive and the only other book on African arms listed was "African Weapons" by Werner & Zirngible (1978). Going through that book there was no evidence of these type swords nor Hausa weapons with T handle hilt, nor crocodile motif, and since the description seems so close to Egertons I must presume Egerton is the source for the Diagram Group reference.
The design and motif is admittedly similar in gestalt to weapons across the entirety of the Sudan, which actually traverses the Sahara to the reaches of the forest kingdoms of the west and across the Sahelian belt. The trade routes which cross diffused materials and culture certainly played a key role in these kinds of anomalies, with the Hausa being prominant merchant traders becoming a prevalent dynamic among other tribes also participating.
Therefore, the classification of this sword as I have suggested is based somewhat objectively on having seen an example in Nilotic context and the references I have provided which are contemporary to the Sudanic campaigns and presumably by a considerably well informed and venerable author. The subjective opinions presented here are however well placed and reflect the broad scope of trade and diffusion in the regions we are studying...which is after all, exactly why we are here!!
Thank you guys,
Jim