Flatfish entire order was John Roxborough Norman's "Monograph of the Flatfishes" published in 1934. New species are described with some regularity and undescribed species likely remain. Hybrids are well known in flatfishes. The Pleuronectidae, of marine fishes, have the largest number of reported hybrids. Two of the most famous intergeneric hybrids are between the European plaice ("Pleuronectes platessa") and European flounder ("Platichthys flesus") in the Baltic Sea, and between the English sole ("Parophrys vetulus") and starry flounder ("Platichthys stellatus") in Puget Sound. The offspring of the latter species pair is popularly known as the hybrid sole and was initially believed to
RV Platessa RV "Platessa" was handed back to the Ministry of Defence (United Kingdom) after 20 years in service, she was replaced by the "RV Corella". In 1968 the RV "Platessa" was sold to private owners (H.J. Lamprell Ltd) and after sinking in Hamilton Dock, Lowestoft in 1975 she was eventually hulked at Lake Lothing where her remains lay for many years. She was recorded as still extant in Lake Lothing on August 19th 2015, and from examination of Google Earth images it seems that she continues to exist as one of two wooden wrecks (the other being the MFV Yellowtail) in