Baltic Sea as species in 2005 and 2018 respectively, having formerly been confused with more widespread relatives. The tiny Copenhagen cockle ("Parvicardium hauniense"), a rare mussel, is sometimes considered endemic, but has now been recorded in the Mediterranean. However, some consider non-Baltic records to be misidentifications of juvenile lagoon cockles ("Cerastoderma glaucum"). Several widespread marine species have distinctive subpopulations in the Baltic Sea adapted to the low salinity, such as the Baltic Sea forms of the Atlantic herring and lumpsucker, which are smaller than the widespread forms in the North Atlantic. A peculiar feature of the fauna is that it contains a
Leptogorgia Leptogorgia Leptogorgia is a genus of soft coral in the family Gorgoniidae. The genus has a widespread distribution with members being found in the eastern Atlantic Ocean from Western Europe to South Africa, the Mediterranean Sea, the Atlantic coasts of North and South America, the Antilles and the Pacific coast of America. Species are found in both shallow and deep waters. An as yet unnamed species of "Leptogorgia" was discovered off the coast of Sonoma County, California in November 2014, near the Gulf of the Farallones and Cordell Bank National Marine Sanctuaries. The World Register of Marine Species lists the