138 Somniosus microcephalus (Bloch & Schneider, 1801) Somniosidae Sleeper sharks Squaliformes Elasmobranchii Greenland shark North Atlantic from the USA and Canada to Greenland in the west and from Portugal to the Barents Sea and Eastern Siberian Sea. Genetic analyses caution that the geographic range of this species may be much narrower, ranging from Canada, Greenland, Iceland, Faroe Islands, and Norway, with occasional records from Cuba, France and Spain (Canary Is.) (Yano et al. 2007, MacNeil et al. 2012, Walter et al. 2017, Simpson et al. 2018). Records from the western Atlantic, including records from the northern Gulf of Mexico and Canadian side off the Davis Strait exhibit evidence of introgressive hybridisation with Pacific Sleeper Shark (<i>Somniosus pacificus</i>) which has been recorded as far north as the Azores Islands (Portugal) (Walter et al. 2017). IGFA 63 N 10 E Somniosus microcephalus ISH 23-1958 1958 Somniosus microcephalus ISH 24-1970 1970 Somniosus microcephalus 350 m ISH 62-1983 1983 Somniosus microcephalus 405 - 408 m AMNH 78352 1986 Somniosus microcephalus ISH 84-1991 1991 Somniosus microcephalus 324 - 332 m