''Bathyembryx istiophasma'', the pallid sailfin, is a

hypothetical species Several species have been assumed to exist, but due to a lack of physical evidence they can only be regarded as potential species. Hypothetical species are usually believed to be extinct. They have caused confusion, as they may have been a separat ...

of fish observed by

William Beebe Charles William Beebe ( ; July 29, 1877 – June 4, 1962) was an American natural history, naturalist, ornithologist, marine biologist, entomologist, explorer, and author. He is remembered for the numerous expeditions he conducted for the New Y ...

on 11 August 1934. He described seeing the species twice during the same dive at depths of and near the coast of

Bermuda Bermuda is a British Overseas Territories, British Overseas Territory in the Atlantic Ocean, North Atlantic Ocean. The closest land outside the territory is in the American state of North Carolina, about to the west-northwest. Bermuda is an ...

Background

The "

bathysphere The ''Bathysphere'' () was a unique spherical deep sea, deep-sea submersible which was unpowered and lowered into the ocean on a cable, and was used to conduct a series of dives off the coast of Bermuda from 1930 to 1934. The ''Bathysphere'' wa ...

," as termed by Beebe, was a new yet primitive invention. It was a rounded steel enclosure with space adequate for two people, its external layer being . On the side, there was a single window made of fused quartz, across and thick. It was fitted with a heavy steel door that had to be bolted on. With no manoeuvrability, the navigation of this steel submersible was solely dependent on the ship it had been attached to. Beebe had no camera brought with him to these great depth, and instead described the species in detail to Else Bostelmann, an artist who proceeded to illustrate his findings. From 1930 to 1934, this submersible was used by Beebe in his deep-sea expedition.

The encounter

Beebe had begun to fathom what he had seen. Within moments, he had prepared a description for the new creature. He had stated it was large for a deep-sea fish, reaching a length of "two feet" at the very least. The fish was completely non-luminous and had a small eye as well as a decently-sized mouth. The pectoral fins were long and wide but filamentous. Two features on the sailfin stood out, according to Beebe. He described the colour as sickly, pale, and olive-coloured. In his own words, "the hue of water-soaked flesh". The caudal fin was reduced, much like a "button". The "vertical" fins, which are assumed to be the anal and dorsal fins, extended greatly beyond its body. He admitted that he did not see the pelvic fins, and thus the illustration subsequently produced lacked them. Beebe called the fish Pallid Sailfin and assigned the

scientific name In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

''Bathyembryx istiophasma'', whose etymology he explained as "a Grecian way of saying it comes from the deep abyss and swims with ghostly sails." He placed it in the family

Cetomimidae Cetomimidae is a family of small, deep-sea beryciform ray-finned fish. They are among the most deep-living fish known, with some species recorded at depths in excess of . Females are known as flabby whalefishes, Males are known as bignose fish ...

Status of existence

Of the five new fish described by Beebe during the Bathysphere dives, none of them were confirmed to exist. The existence of all fishes were supported by his colleague Otis Barton, who descended with him in the submersible.

References

{{Reflist Aquatic cryptids Controversial fish taxa Fish described in 1934

Background

The encounter

Status of existence

See also

References