What was the kingdom east of Nabataea but south of Parthia c. 1st century?

I've been googling this for days, but seem to have had no luck. My area of knowledge is early Roman Judaea, but I'm interested in a Safaitic inscription found in the eastern Jebel Druze (Namara area, to be specific). I cannot for the life of me figure out what kingdom, province, or tribal domain this would fall under from the period 37 CE-97 CE. It's definitely east of the Nabataean Kingdom and definitely south of the Parthian Empire. Was the desert simply a no-man's-land that far east? I'd even be happy if someone could point me the right direction. I can't find anything in the obvious places (Fergus Millar, Benjamin Isaac, Warwick Ball).

Here's a map link to the site, if that would help clarify the location I'm interested in: http://www.satelliteviews.net/cgi-bin/w.cgi?c=sy&UF=-2538736&UN=-3502748&DG=TMB