First report of a sleeper shark (Somniosus sp.) in the western Caribbean, off the insular slope of a coral atoll.

Abstract A sleeper shark (Somniosus sp.) was captured over the insular slope at Glover’s Reef, a coral atoll in Belize. The estimated total length of the individual was ca. 3.0-3.5 m and multiple morphological features diagnostic of a somniosid shark were observed. While the exact species could not be confirmed, it is most likely a Greenland shark (Somniosus microcephalus) or a hybrid between the Greenland shark and the Pacific sleeper shark (Somniosus pacificus). This is the first record of a sleeper shark in the western Caribbean region and further supports the hypothesis that these sharks, best known from polar and subpolar latitudes, occur at depth in tropical regions.