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
History of the forest in Central Europe oak species only three were able to return to Germany and Central Europe from their refuge areas, namely the English oak ("Quercus robur"), sessile oak ("Q. petraea") and downy oak ("Q. pubescens"). By comparison, in North America there are over 80 species of oak. Other types lost considerably in their intraspecific genetic diversity during the return migration such as the white fir ("Abies alba"). Forest flora was pushed back slowly by climatic change. The refuges of the last ice age were probably but not exclusively in southern Europe. A few species on today's Atlantic coast between England and France could