A researcher from Nova Southeastern University’s (NSU) Halmos College of Natural Sciences and Oceanography has discovered a never-before seen anglerfish species living in the deep waters of the Gulf of Mexico. Tracey Sutton, Ph.D., is one of NSU’s experts on deep-sea life and he teamed up with Theodore Pietsch, Ph.D. from the University of Washington to formally describe this new species of anglerfish.
These fish, which were found between 1,000-1,500 meters depth, are a new species of Ceratioid anglerfish (genus Lasiognathus Regan (family Oneirodidae) . The three female specimens found ranged in size from 30-95 mm in length. There are currently only five other described members of the genus, with the new species being unique in its morphology (having a cylindrical, internally pigmented, anterior escal appendage and a pair of elongate distal escal appendages).
The three female specimens collected are considered “type specimens” (i.e. they define the species,) and as such, Dr. Sutton said that they will reside in the Ichthyology Collection at the University of Washington, which is home to the world’s largest deep-sea anglerfish collection.
Anglerfish are one of the more well-known species of deep water fish, most likely as a result of it’s fearsome appearance. They are so named for their characteristic mode of predation, in which a fleshy, bioluminescent growth from the fish’s head (the esca or illicium) acts as a lure . It uses this adaptation to lure prey out of the dark and close enough to eat the organism. The source of luminescence is symbiotic bacteria that dwell in and around the esca. In some species, the bacteria recruited to the esca are incapable of luminescence independent of the anglerfish, suggesting they have developed a symbiotic relationship as the bacteria are unable to synthesise all of the chemicals necessary for luminescence without interacting with the fish . Electron microscopy of these bacteria in some species reveals they are Gram-negative rods that lack capsules, spores, or flagella, and possess double-layered cell walls and mesosomes.
It is only the female anglerfish that posses this luminous esca however, with males (which are significantly smaller than females) having no need for such an adaptation. In lieu of continually seeking the vast abyss for a female, it has evolved into a permanent parasitic mate. When a young, free-swimming male angler encounters a female, he latches onto her with his teeth. Over time, the male physically fuses with the female, connecting to her skin and bloodstream and losing his eyes and all his internal organs except the testes. A female will carry six or more males on her body. There are around 200 species of anglerfish found in the deep waters of the worlds oceans, with the majority found in the murky depths of the Atlantic and Antarctic oceans.
Speaking of the researchers recent discovery, Dr Sutton says:
“As a researcher, the one thing I know is that there’s so much more we can learn about our oceans. Every time we go out on a deep-sea research excursion there’s a good chance we’ll see something we’ve never seen before – the life at these depths is really amazing.”
Header Photo Credit:
- Theodore W. Pietsch, Tracey T. Sutton. A New Species of the Ceratioid Anglerfish GenusLasiognathusRegan (Lophiiformes: Oneirodidae) from the Northern Gulf of Mexico. Copeia, 2015; 103 (2): 429 DOI:10.1643/CI-14-181