The UNESCO-IOC Register of Marine Organisms (URMO) was the first attempt to compile an electronic list of all marine species during the 1990’s. It was invented and developed by Jacob van der Land at the National Museum of Natural History, Leiden (and several colleagues). The URMO list is no longer actively maintained and is completely adopted by the World Register of Marine Species (WoRMS). URMO and other databases (such as the European Register of Marine Species) were the starting points for the current World Register of Marine Species.

URMO is hosted by the Flanders Marine Institute (VLIZ) as a contribution to the "International Oceanographic Data and Information Exchange" (IODE) programme of the "Intergovernmental Oceanographic Commission" (IOC) of UNESCO, and as a memory to its creator Jacob van der Land.

Dr. Jacob van der Land passed away on Sunday 23 October 2011, 76 years old. He spent many of his productive years - before and after his retirement - on URMO, ERMS, and WoRMS. He was curator of worms (Vermes) and head of the department of Invertebrates of the former Rijksmuseum van Natuurlijke Historie (RMNH), later National Museum of Natural History, which presently is known as the Netherlands Centre for Biodiversity Naturalis at Leiden, The Netherlands.