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A note about potential renaming of the native Great Lakes opossum shrimp, Mysis relicta, to Mysis diluviana

Provided by David Reid and Rochelle Sturtevant
NOAA National Center for Research on Aquatic Invasive Species (NCRAIS)
April 2007

The mysid species native to North American Great Lakes is officially known as Mysis relicta (Integrated Taxonomic Information System (ITIS), http://www.itis.gov), but a new name - Mysis diluviana - has been proposed and used in the European literature, and appears in at least one recent North American publication (Dooh et al. 2006). However, the name change has not been verified or accepted in official biological nomenclature sources and does not, for example, appear under ITIS.

Väinölä et al. (1994) separated species previously identified as Mysis relicta into four separate species based on genetic analysis. They report that each of the four species has distinct genetic and morphological characteristics, although characteristics like length and shape of the setae (hairlike bristles) have to be examined to tell them apart. Species in the new group are referred to as “the Mysis relicta group species” (Väinölä et al. 1994; Audzijonytë and Väinölä 2005). According to the new grouping, Mysis relicta occurs in northern Europe and brackish portions of the Baltic Sea; M. salemaai is the mysis in offshore Baltic Sea, the British Isles, and southern Scandinavia; M. segerstralei has a circumpolar distribution along the Arctic coasts and islands of Eurasia and North America and also occurs in lakes of these northern regions; and M. diluviana inhabits continental freshwater lakes of the the once-glaciated northern North America, including the Great Lakes (Audzijonytë and Väinölä 2005).


Väinölä, R., J.Riddoch, R.D. Ward & R.I. Jones, 1994. Genetic zoogeography of the Mysis relicta group (Crustacea: Mysidacea) in northern Europe and North America. Canadian Journal of Fisheries and Aquatic Sciences, 51: 1490-1505.

Audzijonytë A, Väinölä, R (2005) Diversity and distributions of circumpolar fresh- and brackish-water Mysis (Crustacea: Mysida): descriptions of M. relicta Lovén, 1862, M. salemaain n sp., M. segerstralei n. sp.) & M. diluviana n. sp., based on molecular and morphological characters. Hydrobiologia, 544: 89-141.

Dooh, R.T., J. Adamowisc, and P.D.N. Hebert (2006). Comparative phylogeography of two North American ‘glacial relict’ crustaceans. Molecular Ecology, 15: 4459-4475.