A record about Juvenile Malacosteidae of North Male Atoll in Maldives

I encountered two individuals of Juvenile Malacosteidae at 24th Dec, 2015 in North Male Atoll of Maldives by Black water Dive^®. They has gut outside the body before it transforms into an adult. Maybe, It's useful for floating. And, that huge gut is possible to eat a lot of bait, it can grow big.  But, maybe external gut go in the body when to be adult. However, detailed information until an adult is not known still now.

External gut is about 3.5 times longer of body.

Depth -5m, SL about 30mm.

Eyes small and oval.

Body is very slender.

Photographer: Ryo Minemizu

Information about individual of pictures.
Depth: -5m. Sea temperature: 29 degree. Body: very slender. Eyes: small and oval. External gut: about 3.5 times longer of body. Chromatophore: small orange, 9(or 10) on dorsal, obscurity at ventral.
The appearance of Eustomias of Melanostomiinae Parr, 1927 is looks similar to this species. However, this species of ventral fin membrane is development. (Eustomias is not development.)

Species information
There adult lives in the Bathypelagic (1,000 - 3,000m).

Genus and species of Malacosteidae is following.
This time, I use for Family name of Malacosteidae so as to follow in (Okiyama M. ed (2014)).
Malacosteidae known about fourteen species at three genus from worldwide.

• Aristostomias
• Aristostomias grimaldii Zugmayer, 1913
• Aristostomias lunifer Regan & Trewavas, 1930
• Aristostomias polydactylus Regan & Trewavas, 1930
• Aristostomias scintillans (Gilbert, 1915)
• Aristostomias tittmanni Welsh, 1923
• Aristostomias xenostoma Regan & Trewavas, 1930

• Malacosteus
• Malacosteus australis Kenaley, 2007
• Malacosteus niger Ayres, 1848

• Photostomias
• Photostomias atrox (Alcock, 1890)
• Photostomias goodyeari Kenaley & Hartel, 2005
• Photostomias guernei Collett, 1889
• Photostomias liemi Kenaley, 2009
• Photostomias lucingens Kenaley, 2009
• Photostomias tantillux Kenaley, 2009

Species of Indian ocean.

• Aristostomias grimaldii Zugmayer, 1913
• Aristostomias lunifer Regan & Trewavas, 1930
• Aristostomias polydactylus Regan & Trewavas, 1930
• Aristostomias xenostoma Regan & Trewavas, 1930

• Malacosteus australis  Kenaley, 2007
• Malacosteus niger Ayres, 1848

• Photostomias atrox (Alcock, 1890)
• Photostomias liemi Kenaley, 2009

REFERENCES
Okiyama M. ed (2014) An Atlas of Early Stage Fishes in Japan Second Edition Tokai University Press, Japan. :217–268. (in Japanese).

Kenaley, C.P. (2009). Revision of Indo-Pacific species of the loosejaw dragonfish genus Photostomias (Teleostei: Stomiidae: Malacosteinae). Copeia, (1) :175-189.

Fishbase.org
http://www.fishbase.org/summary/FamilySummary.php?ID=91

WoRMS taxon details. Malacosteinae Gill, 1890
http://www.marinespecies.org/aphia.php?p=taxdetails&id=154693