preferred_name: a 1,3-diacyl-2-(9Z,12Z-octadecadienoyl)-glycerol + an N-(omega-hydroxy-ultra-long chain fatty acyl)-sphingoid base <=> an N-[omega-(9Z,12Z-octadecadienoyloxy)-O-ultra-long chain fatty acyl]-sphingoid base + a 1,3-diacylglycerol