Gah! The initial poster had it right. It is "Ti Kar" not "Tikar". The prior precedent in publication, the A to Z Guide to Babylon 5, wrote their name as Ti Kar, and it was only during late AOG period I think that people started running it together as "Tikar" instead.
Nitpick, yes, but it is something that ruffles my feathers for some reason
There is no official background for the Ti Kar, unless Mongoose introduced some (I did buy the Galaxy Guide, so I guess I could check!). I wrote up a background for them at one point, explaining them to be basically "giant lungfish" -- amphibious aliens with a major psychological impairment in that they suffered from agoraphobia (fear of the outdoors). In the background I wrote, this fear of confined spaces led them to develop automated technologies to a degree uncommon for the B5 universe, and they relied on automatons to perform many functions that would normally be done by individuals. This in turn explains why the Ti Kar ship was noted as being so large -- in order to travel the stars, the Ti Kar had to build enormous starships wherein they could recreate an artificial environment similar to that on their homeworld. That way the crews would not feel claustrophobic aboard the ships. I also added the note that Ti Kar could not pilot fighters at all, as the action of being put into such a confined space would quickly drive the Ti Kar irreprably insane.
The above is of course complete fiction and just something that I wrote at one point because I was trying to flesh things out in the B5 universe. I surmised that the Ti Kar were the "Walkers of the Younger Races", an advanced species intent on scientific progress. They don't have much to do with outsiders and travel around in their (cloaked) giant starships performing various scientific surveys. Trade with their neighbors is limited, but fruitful.
Lacking anything better or more substantial, that would at least provide a building block for later development -- though now I am curious as to what Mongoose did with the Ti Kar in their book...