Deepest eel

Eels are ray-finned fishes belonging to the order Anguilliformes. Within that order, there are eight suborders, one of which, Synaphobranchoidei (aka cut-throat eels), are common in the deep sea. On 14 May 2014, Dr Alan Jamieson and Dr Thomas Linley (both then at University of Aberdeen, UK) deployed a deep-sea vehicle known as Abyssal-Lander to 6,068 metres (19,908 feet) deep in the Kermadec Trench off New Zealand from the research vessel RV Thomas G Thompson. Included in those photos was the synaphobranchid Ilyophis robinsae. To date, this is the only observation of an anguilliform at hadal depths - i.e., greater than 6,000 metres (19,685 feet) deep - and therefore is the deepest true eel ever recorded. The findings of the research were published in Deep Sea Research I on 7 May 2016.

Other fish species, such as the Ophidiidae are referred to as "cusk eels" are found at even greater depths, but are not true Anguilliformes - rather the name derives from “eel-like”. In 1970, a cusk eel was recorded in the hadalpelagic zone of the ocean at a depth of 8,370 m (27,460 ft) in the Puerto Rico trench, the deepest point in the Atlantic Ocean.

The species was first described in a paper by Sulak & Shcherbachev in 1997. Its epithet "robinsae" is in recognition of marine biologist Catherine Robins, who has made great strides in expanding our knowledge of cut-throat eels.