Native
N. borealis is a large (up to 33 mm) Cymothoid isopod similar in general shape to Eurydice and Cirolana. The exopods of the uropods are narrower and shorter than the endopods, whilst the pleotelson is broad, narrowing to a point. The margins of the endopods, exopods and pleotelson are fringed by many plumose setae.
This is a sublittoral scavenger, which can be collected in deeper water using baited traps, especially at night (during the day the species burrows into seabed sediment). It is not infrequently encountered on retrieved bait whilst fishing in deep water.
Keable, S. J. & Bruce, N. L. 1997. Redescription of the North Atlantic and Mediterranean Species of Natatolana (Crustacea: Isopoda: Cirolanidae). Journal of the Marine Biological Association of the United Kingdom 77, 655-705.
Naylor, E. & A. Brandt. 2015. Intertidal Marine Isopods. Synopses of the British Fauna (New Series), No. 3. Field Studies Council, for The Linnean Society of London.
World Register of Marine Species (WoRMS): https://www.marinespecies.org/aphia.php?p=taxdetails&id=118859
Ocean Biodiversity Information System (OBIS) distribution map: https://mapper.obis.org/?taxonid=118859