When I first saw the call for pathological aeolian landforms, I thought it would be fun to find some snowdunes in Antartica. Did you realize there was an enormous hole in GE's coverage of that continent? I didn't. Suddenly, the Lemurians seem more probable. I didn't find snowdunes that appealed to me, and I found I was having a hard time distinguishing aeolian forms from ice flow-induced structures.
So I went to the Arabian Peninsula's empty quarter, and was somewhat disconcerted to find this. The dimensions of this image are about 91 x 61 miles. This is not a place I'd want to be without a helicopter at my beck and call. Just in case I've misremembered again, I did look this up on Wikipedia, and can't really see the distinction between linear and longitudinal dunes. However, I did find this passage, which gives me a little more confidence:Longitudinal dunes (also called Seif dunes, after the Arabic word for "sword"), elongate parallel to the prevailing wind, possibly caused by a larger dune having its smaller sides blown away. Seif dunes are sharp-crested and are common in the Sahara. They range up to 300 m (980 ft) in height and 300 km (190 mi) in length. In the southern third of the Arabian Peninsula, a region called the Empty Quarter because of its total lack of population, a vast erg called Rub al Khali conatins seif dunes that stretch for almost 200 km and reach heights of over 300 m.