Linophryne arborifera

The literal translation of Linophryne arborifera from Greek is "tree-bearing flax-toad" (λίνον+φρύνος, arboriferous). Typical of the suborder, the female Linophryne has an esca, a luminous lure on her head derived from a fin ray, but she also possesses a branching hyoid barbel hanging from the lower jaw. The barbel filaments contain many more globular, bioluminescent organs. Linophrynids are further differentiated from other ceratioid families in having 3 dorsal fin- and anal fin-rays (rarely 2 to 4), 5 branchiostegal rays (rarely 4), and a sinistral anus (one which opens to the left). The eyes and nostrils of linophrynid males are very well developed; the eyes are unique among ceratioids in being forward-facing with a somewhat tubular shape.{{cite book |last1=Bertelsen |first1=Erik |last2=Pietsch |first2=Theodore W. |title=The ceratioid anglerfishes of Australia, Records of the Australian Museum|volume=35|issue=2 |date=1983-06-14 |page=94 |url=https://www.biodiversitylibrary.org/page/64094924#page/106/mode/1up |doi=10.3853/j.0067-1975.35.1983.303|access-date=2 March 2025}}

This species is differentiated from congeners by characters of the esca and barbel;{{Clarify|reason=List the characters here if you have access to Bertelsen's papers|date=March 2025}}{{cite journal |last1=Waterman |first1=Talbot Howe |title=Studies on deep-sea angler-fishes (Ceratioidea) |journal=Bulletin of the Museum of Comparative Zoology at Harvard College |date=1939 |volume=85 |pages=85–89 |url=https://www.biodiversitylibrary.org/page/4538043#page/114/mode/1up |access-date=2 March 2025}} males of the genus cannot be differentiated in morphology. L. arborifera's esca is trifid, longer than the ilicial stem + bulb, has been likened to a pearl onion, and contains luminous bacteria. The barbels, likened to fronds of seaweed, do not contain bacteria but complex paracrystalline photogenic granules;{{Clarify|date=March 2025}} the many branching barbels are as long as the body and has filamentous tips. The esca is ectodermal in origin whereas the barbel organs may be derived from the mesoderm.{{cite journal|last1=Hansen|first1=Kjold|last2=Herring|first2=Peter J.|title=Dual bioluminescent systems in the anglerfish genus Linophryne (Pisces: Ceratioidea)|journal=Journal of Zoology|volume=182|issue=1|pages=103–124|date=1977|url=https://www.researchgate.net/publication/230018708|doi=10.1111/j.1469-7998.1977.tb04144.x}} At a length of up to {{Convert|77|mm|in}}, females are significantly larger than the males, which reach only about {{Convert|15|mm|in}}. Both sexes are pigmented after metamorphosis, being black in color. They have no scales and gelatinous skin.

Linophryne arborifera is bathypelagic, typically inhabiting depths of {{Convert|200|-|1000|m|ft}},{{cite web |title=Linophryne arborifera Regan 1925 |url=https://www.fishbase.ca/summary/17013 |website=fishbase.ca |publisher=FishBase |access-date=2 March 2025}} with the holotype being collected at a depth of {{Convert|200|-|300|m|ft}} in the north Atlantic.{{cite journal |last1=Regan |first1=Charles Tate |title=New ceratioid fishes from the N. Atlantic, the Caribbean Sea, and the Gulf of Panama, collected by the 'Dana.' |journal=Annals and Magazine of Natural History |date=1925 |volume=9 |issue=15 |url=https://www.tandfonline.com/doi/abs/10.1080/00222932508633247|doi=10.1080/00222932508633247|page=564|url-access=subscription }} The deepest record for females is {{Convert|1645|m|ft}}, while a male was collected {{Convert|4000|m|ft}} down.{{cite journal |last1=Grey |first1=Marion |title=The distribution of fishes found below a depth of 2000 meters |journal=Fieldiana, Chicago Natural History Museum |date=1956 |volume=36 |pages=273–275 |url=https://www.biodiversitylibrary.org/item/20739#page/211/mode/1up |access-date=2 March 2025}} The species is thought to inhabit tropical and subtropical oceans, with specimens also found in the Pacific and Indian Oceans,{{Cite WoRMS|title= Linophryne arborifera Regan, 1925|id=159181}} although the IUCN only considers Atlantic records to be of this species.

Recorded prey of the genus Linophryne include fishes and crustaceans. Attached males obtain their nutrition from the female. They attach to the female with their jaws on her ventral surface. Blood vessels and tissues between them become integrated, allowing nutrients to pass from the female to the male.{{cite journal|last1=Anderson|first1=M. Eric|last2=Leslie|first2=Robin W.|title=REVIEW OF THE DEEP-SEA ANGLERFISHES (LOPHIIFORMES: CERATIOIDEI) OF SOUTHERN AFRICA|journal=Ichthyological Bulletin|volume=70|pages=1–32|date=2001|url=http://www.bioline.org.br/request?fb01002}}

Based on finding empty stomachs in captured free-living males, linophrynid males are thought to be unable to feed during their free-living stage after metamorphosis. Also, the "short and stout" denticulars of the upper and lower jaws of these males do not seem suitable for prey capture, and the alimentary canal is undeveloped. Current understanding is that free-living males die after a few months if they do not attach to a female.

In the family Linophrynidae, males are obligatory sexual parasites.{{cite journal|last1=Munk|first1=Ole| last2=Bertelsen|first2=E|title=Histology of the attachment between the parasitic male and the female in the deep-sea anglerfish Haplophryne mollis (Brauer, 1902) (Pisces, Ceratioidei)| journal=Videnskabelige Meddelelser Fra Dansk Naturhistorisk Forening|volume=144|page=49-74|date=1983}} Attached males are nearly always found upside down, facing forward, and attached to the belly close to the anus. In all specimens found so far, only one male is attached to each female, which differs from some other angler fish species.{{Citation needed|date=March 2025}} Females without attached males and free-living males do not have well-developed gonads, so it seems that they must be attached for maturation and reproduction to occur. A 77-mm female Linophryne arborifera, with a 15-mm parasitic male, was observed to have numerous eggs embedded in a gelatinous mass (the "egg raft" or "veil", a characteristic of all lophiiform fishes) protruding from the genital opening; the eggs, 0.6–0.8mm in diameter, are among the largest known for any ceratioid.{{cite journal |last1=Bertelsen |first1=E |title=Notes on Linophrynidae 5: a revision of the deepsea anglerfishes of the Linophryne arborifera-group (Pisces, Ceratoidei) |journal=Steenstrupia |date=1980 |volume=6 |issue=6 |pages=29–70 |issn=0375-2909|url=https://eurekamag.com/research/021/437/021437497.php |access-date=2 March 2025}}{{cite journal |last1=Pietsch |first1=Theodore W. |title=Dimorphism, parasitism, and sex revisited: modes of reproduction among deep-sea ceratioid anglerfishes (Teleostei: Lophiiformes) |journal=Ichthyological Research |date=August 2005 |volume=52 |issue=3 |pages=207–236 |doi=10.1007/s10228-005-0286-2 |url=https://link.springer.com/article/10.1007/s10228-005-0286-2 |issn=1341-8998|access-date=1 March 2025|url-access=subscription }}

{{Reflist}}

• {{ITIS |id=622980 |taxon=Linophryne arborifera |accessdate=18 April 2006}}
• {{FishBase | genus = Linophryne |species = arborifera | month = January | year = 2006}}
• Tony Ayling & Geoffrey Cox, Collins Guide to the Sea Fishes of New Zealand, (William Collins Publishers Ltd, Auckland, New Zealand 1982) {{ISBN|0-00-216987-8}}
• [http://www.frogfish.ch/deepsea-anglerfish.html Frogfish page on anglerfish, including linophryne arborifera]
• [https://web.archive.org/web/20050330063903/http://www.socgenmicrobiol.org.uk/pubs/micro_today/pdf/110203.pdf 2002 article in Microbiology Today on bioluminescence in marine animals]

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arborifera

Category:Deep sea fish

Category:Fish described in 1925

Category:Taxa named by Charles Tate Regan