Mark
Good comment - thanks. The deep curvature and the blade wide fullers are not very typical. Only the pommel ears suggest the affinity to the Black sea Yataghan.
Some time ago (I can not find the thread) I posted a similar one (The central one in the photo below):
It was suggested that it is converted from a bayonet and even the bayonet model and make were suggested. The fact that the fullers are etched in a pattern similar to this found on some Kindjal / Qamas was also discussed and suggested as a later addition to the converted bayonet.
The similarity of this sword to #1 above is staggering. Even the ribbed grips and pommel ears are similar. Also here the fullers are etched (so says the text in the book) so I would think it is NOT a converted item but some close relative of the Black Sea Yataghan, may be closer to the Caucasus region.