Summary

All studied bodies with both solid surfaces and thick atmosphere now known to exhibit sand dunes (what about Triton and Pluto?)
Titan's dunes cover ~20% of the surface, all within 35 degrees of the equator
Dunes are longitudinal; presumably old like longitudinal dunefields on Earth
Particles calculated to be of sand size (180-250 microns)
Spacing 1-3 km, heights 30-150m
Not made of ice grains – hydrocarbons consistent
Interdunes show substrate; dunes seem to cover a variety of terrains

All studied bodies with both solid surfaces and thick atmosphere now known to exhibit sand dunes (what about Triton and Pluto?)