Natural arsenolipids are analogues of neutral lipids, like monoglycerides, glycolipids, phospho- and also phosphonolipids. They have been found in microorganisms, fungi, plants, lichens, in marine mollusks, sponges, other invertebrates, and in fish tissues. Arsenolipids are thought to be end products of arsenate detoxification processes, involving reduction and oxidative methylation and adenosylation.

Source:
Valery M. Dembitsky, Dmitrii O. Levitsky, Arsenolipids,  Progress in Lipid Research,  43/5 (2004) 403-448.