Dreamers that will Give You Nightmares

            Using a natural, bioluminescent lure is a successful method of attracting prey, but the lures come in many different forms. The family Oneirodidae, or dreamers, use another variation of a modified dorsal spine as a lure, but it appears much shorter than that of the average anglerfishes. In addition to their unique illicium, members of Oneirodidae have several other adaptations giving them a highly unique and slightly terrifying appearance.

                                 

                                 Fig. 1 Bulbous Dreamer, Oneirodes eschrichtii  -                   (http://fishesofaustralia.net.au/home/family/161)

            Like the Ceratioid seadevils, Oneirodidae fishes appear deep black in colour, diminishing their visibility in water. With only the bright glow of the illicium, other fish are instantly drawn toward the sneaky predators. Based on the scary appearance of the various Oneirodidae fishes, it should not be surprising that they act as predators.

Fig. 2 A female Longhead Dreamer, Chaenophryne longiceps, collected in the Tasman Sea on the 2003 NORFANZ Expedition (http://fishesofaustralia.net.au/home/family/161)

The fishes are typically found between 11-29 centimetres and fall primarily on the shorter end of the spectrum (Jónsson and Palsson, 1999), but regardless of their smaller size, there is something threatening about their appearance. Their globular bodies and short caudal and pectoral fins look like an ineffective means of locomotion, but they somehow thrive as ambush predators.

Fig. 3 Haenophryne melanorhabdus SL 52 mm with an attached parasite 15 mm long (http://tinyurl.com/mtwtwrk)

            Oneirodidae fishes are clearly doing well in means of survival, as they have been found throughout a variety of waters. The first species was captured in 1973 off the west coast, but have also been captured with bottom trawl in the Víkuráll area and the southeast coast of Iceland (Jónsson and Palsson, 1999). Of the deepsea anglerfishes, the family Oneirodidae is the largest and most diverse family within the suborder Ceratioidei, but is also the least well known (Pietsch, 1973). The different fish within this family may hold another key to discovering information on how and when the evolution of deepsea fishes occurred, but the elusive nature of Oneirodidaes poses a challenge in studying their traits and behaviour.

References

      Jónsson, G. and Palsson, J. (1999). Fishes of the suborder Ceratioidei (Pisces: Lophiiformes) in Icelandic and adjacent waters. Rit Fiskideildar, [online] 16, pp.197-207. Available at: https://www.researchgate.net/profile/Jonbjorn_Palsson/publication/268435797_Fishes_of_the_suborder_Ceratioidei_Pisces_Lophiiformes_in_Icelandic_and_adjacent_waters/links/55ff43a808aeafc8ac8b9a25/Fishes-of-the-suborder-Ceratioidei-Pisces-Lophiiformes-in-Icelandic-and-adjacent-waters.pdf [Accessed 25 Apr. 2017].

      Pietsch, T. (1973). A New Genus and Species of Deep-Sea Anglerfish (Pisces: Oneirodidae) from the Northern Pacific Ocean. Copeia, [online] 1973(2), p.193. Available at: http://www.jstor.org/stable/pdf/1442957.pdf [Accessed 28 Apr. 2017].

      Fig. 1: Bray, D. (2017). Bulbous dreamer, Oneirodes eschrichtii. [image] Available at: http://fishesofaustralia.net.au/home/family/161 [Accessed 26 Apr. 2017].

      Fig. 2: Bray, D. (2017). A female Longhead Dreamer, Chaenophryne longiceps, collected in the Tasman Sea on the 2003 NORFANZ Expedition. [image] Available at: http://fishesofaustralia.net.au/home/family/161 [Accessed 26 Apr. 2017].

     Fig. 3: Prokofiev, A. (2017). Chaenophryne melanorhabdus SL 52 mm with an attached parasite 15 mm long:. [image] Available at: http://download.springer.com/static/pdf/17/art%253A10.1134%252FS0032945214050075.pdforiginUrl=http%3A%2F%2Flink.springer.com%2Farticle%2F10.1134%2FS0032945214050075&token2=exp=1493369269~acl=%2Fstatic%2Fpdf%2F17%2Fart%25253A10.1134%25252FS0032945214050075.pdf%3ForiginUrl%3Dhttp%253A%252F%252Flink.springer.com%252Farticle%252F10.1134%252FS0032945214050075*~hmac=e181919da3230f8a00e00f719afd2a421a17088e0505a0a6be432e500a921fe8 [Accessed 27 Apr. 2017].