Although there are a number of described Aequorea species, much uncertainty remains regarding their taxonomy and nomenclature. By far the best known species is A. victoria of the northeastern Pacific, which under some conditions can produce a greenish light around the margin of its bell. Aequorea victoria jellyfish are nearly transparent. They are around 8 to 10 cm in diameter and 50 g, with light organs consist of about 100 granules distributed evenly along the edge of the bell (Shimomura 1995). This is the jellyfish from which the luminescent protein aequorin and the associated fluorescent molecule Green Fluorescent Protein (GFP) were extracted and purified (and eventually cloned). GFP has proved to be an invaluable marker protein in molecular biology and biomedical research and aequorin is used as a calcium probe; three researchers shared the 2008 Nobel Prize in Chemistry for their roles in discovering GFP and developing it as a valuable research tool.
For more information about Aequorea and GFP, see this excellent resource by jellyfish expert Claudia Mills. Zimmer (2009) and Tsuji (2010) review the discovery and development of GFP and Zimmer's Green Fluorescent Protein website can be explored here. A more personal account of these discoveries is provided by Shimomura (1995, 2005), who pioneered work on Aequorea.
Aequorea aequorea (Forskål, 1775), Aequorea africana Millard, 1966, Aequorea albida Agassiz, 1862, Aequorea australis Uchida, 1947, Aequorea coerulescens (Brandt, 1838), Aequorea conica Browne, 1905, Aequorea cyanea de Blainville, 1834, Aequorea eurhodina Péron & Lesueur, 1809, Aequorea floridana (Agassiz, 1862), Aequorea forskalea (Forskål, 1775), Aequorea globosa Eschscholtz, 1829, Aequorea krampi Bouillon 1984, Aequorea macrodactyla (Brandt, 1835), Aequorea minima Bouillon 1985, Aequorea papillata Huang & Xu 1994, Aequorea parva Browne, 1905, Aequorea pensilis (Eschscholtz, 1829), Aequorea phillipensis Watson 1998, Aequorea tenuis (Agassiz, 1862), Aequorea victoria (Murbach and Shearer, 1902), Aequorea vitrina Gosse, 1853