Editing Splendid lanternshark

{{Short description|Species of shark}}
{{speciesbox
| name = Splendid lanternshark
| image =
| status = LC
| status_system = IUCN3.1
| status_ref=<ref name="iucn status 18 November 2021">{{cite iucn |author=Rigby, C.L. |author2=Ebert, D.A. |author3=Herman, K. |date=2020 |title=''Etmopterus splendidus'' |volume=2020 |page=e.T161448A124487132 |doi=10.2305/IUCN.UK.2020-3.RLTS.T161448A124487132.en |access-date=18 November 2021}}</ref>
| genus = Etmopterus
| species = splendidus
| range_map = Etmopterus splendidus distmap.png
| range_map_caption = Range of the splendid lanternshark (in blue)
| authority = [[Kazunari Yano|Ka. Yano]], 1988
}}
{{Portal|Sharks}}

The '''splendid lanternshark''' ('''''Etmopterus splendidus''''') is a [[shark]] of the [[family (biology)|family]] [[Etmopteridae]] found in the western [[Pacific]] at depths between 120 and 210 m. Through the classification of ''Etmopterus'' species into several [[clade]]s based on the positioning of their bioluminescent photophores, the splendid lanternshark can be considered a member of the ''Etmopterus pusillus'' clade.<ref name=":2" />

Its length is up to 30&nbsp;cm.<ref>{{Cite web |last=Yano |first=K |date=1988 |title=A New Lanternshark Etmopterus splendidus from the East China Sea and Java Sea. |url=https://www.jstage.jst.go.jp/article/jji1950/34/4/34_4_421/_pdf/-char/en |website=Japanese Journal of Ichthyology}}</ref>

Reproduction is [[ovoviviparous]].

== Physiological features and adaptations ==

=== Bioluminescence ===

==== Patterning ====
The patterns of bioluminescent [[photophore]]s found on the [[Rostrum (anatomy)|rostrum]], dorsal area, and around the spine of splendid lantern sharks are similar to those of other members of the family [[Etmopteridae]], namely ''[[Velvet belly lanternshark|Etmopterus spinax]]'' and ''[[Slendertail lanternshark|Etmopterus molleri]]'', but there are important differences.<ref name=":0">{{Cite journal |last1=Duchatelet |first1=Laurent |last2=Pinte |first2=Nicolas |last3=Tomita |first3=Taketeru |last4=Sato |first4=Keiichi |last5=Mallefet |first5=Jérôme |date=December 2019 |title=Etmopteridae bioluminescence: dorsal pattern specificity and aposematic use |journal=Zoological Letters |language=en |volume=5 |issue=1 |pages=9 |doi=10.1186/s40851-019-0126-2 |issn=2056-306X |pmc=6402137 |pmid=30873292 |doi-access=free }}</ref> Dorsal photophores in all three species are arranged in three lines running the length of the back, but what distinguishes the splendid lanternshark from the other species is the longitudinal line of the dorsal area. This line is different from other species' in that it is significantly thicker.<ref name=":0" /> The bioluminescence spectra wavelength of ''Etmopterus splendidus'' is 476 nm, which is the wavelength light is present in  the depths they are normally found.<ref name=":1">{{Cite journal |last1=Mizuno |first1=Gaku |last2=Yano |first2=Daichi |last3=Paitio |first3=José |last4=Endo |first4=Hiromitsu |last5=Oba |first5=Yuichi |date=2021-11-05 |title=Etmopterus lantern sharks use coelenterazine as the substrate for their luciferin-luciferase bioluminescence system |journal=Biochemical and Biophysical Research Communications |language=en |volume=577 |pages=139–145 |doi=10.1016/j.bbrc.2021.09.007 |issn=0006-291X|doi-access=free }}</ref><ref name=":3">{{Cite journal |last1=Claes |first1=Julien M. |last2=Nilsson |first2=Dan-Eric |last3=Straube |first3=Nicolas |last4=Collin |first4=Shaun P. |last5=Mallefet |first5=Jérôme |date=2014-03-10 |title=Iso-luminance counterillumination drove bioluminescent shark radiation |journal=Scientific Reports |language=en |volume=4 |issue=1 |pages=4328 |doi=10.1038/srep04328 |pmid=24608897 |issn=2045-2322|pmc=3948070 }}</ref> This is significant as it allows their bioluminescence to hide the sharks from predators and prey. 

The photophores of ''Etmopterus splendidus'' are typical of etmopterid sharks, "i.e. a cluster of photocytes enclosed in a pigmented sheath and surmounted by pigmented and lens cells" (Claes, et. al.).<ref name=":2">{{Cite journal |last1=Claes |first1=Julien M. |last2=Sato |first2=Keiichi |last3=Mallefet |first3=Jérôme |date=2011-09-30 |title=Morphology and control of photogenic structures in a rare dwarf pelagic lantern shark (Etmopterus splendidus) |url=https://www.sciencedirect.com/science/article/pii/S0022098111002486 |journal=Journal of Experimental Marine Biology and Ecology |language=en |volume=406 |issue=1 |pages=1–5 |doi=10.1016/j.jembe.2011.05.033 |issn=0022-0981}}</ref> Photophores are about 100 μm in diameter.<ref name=":2" />

Splendid lanternsharks are considered to have nine distinct luminous zones: Rostral, Ventral, Lower caudal, Upper caudal, Infracaudal, Mandibular, Pectoral, Pelvic, Latera, and Infrapelvic. <ref name=":2" />

Of these zones, the ventral zone is, on average, the largest zone, covering almost 90% of the organism's ventral area.<ref name=":2" /> In the ventral zone, the photophores are distributed with increasing density towards the midline, a pattern that matches the way surface light is seen from below.<ref name=":3" />

==== Mechanism ====
There is some debate about the exact mechanism of ''Etmopterus splendidus''{{'}} bioluminescence, although it is agreed that ''Etmopterus'' species utilize intrinsic and not symbiotic bioluminescence. The debate centers around the presence of a lucerfin system that uses [[coelenterazine]] and coelenterazine-dependent [[luciferase]] in the photophores of ''Etmopterus'' species. Some papers <ref>{{Cite journal |last1=Renwart |first1=Marie |last2=Mallefet |first2=Jérôme |date=October 2013 |title=First study of the chemistry of the luminous system in a deep-sea shark, Etmopterus spinax Linnaeus, 1758 (Chondrichthyes: Etmopteridae) |url=http://dx.doi.org/10.1016/j.jembe.2013.07.010 |journal=Journal of Experimental Marine Biology and Ecology |volume=448 |pages=214–219 |doi=10.1016/j.jembe.2013.07.010 |issn=0022-0981}}</ref> have found none of these compounds to be present while others <ref name=":1" /> have. Defense of the usage of this form of bioluminescence stems from the detection of these compounds in samples of ''Etmopterus'' species' skin as well as the hypothesized feeding of ''Etmopterus'' species on luminous [[copepod]]s and [[comb jellies]] that contain coelenterazine, a manner of obtaining coelenterazine found in other bioluminescent species.<ref name=":1" /> Continued detection of coelenterazine and the related luciferase are needed to confirm the mechanism used, and evidence of ''Etmopterus'' eating these species. 

Bioluminescence in splendid lanternsharks is controlled by both hormonal and neurological means.<ref name=":2" /> [[Melatonin]] (MT) and [[prolactin]] (PRL) have been found to be light-inducing hormones; [[Α-Melanocyte-stimulating hormone|α-melanocyte stimulating hormone]] has been found to be a light-inhibiting hormone; and [[Γ-Aminobutyric acid|GABA]] has been found to be a light-inhibiting neurotransmitter.<ref name=":2" />

While many species alter the intensity of the light they produce in order to mimick the changes of surface light intensity, splendid lanternsharks - like other bioluminescent sharks - produce a constant light but change their depth to adjust how potential predators below them see the light.<ref name=":3" />

==== Behavioral ====
Skin photophores surrounding the defensive dorsal spines present on ''E. splendidus'' show a pattern supporting an [[Aposematism|aposematic]] function for the bioluminescence of this species. Aposematism is the use of warning coloration to inform potential predators that an animal is poisonous or venomous. Despite the absence of poison or venom in ''E. splendidus'', aposematic mimicry is believed to be used in its bioluminescence surrounding these defensive dorsal spines. This mechanism was documented for the first time ''in situ'' by video recordings in 2016.<ref name=":0" />

''E. splendidus'' has a translucent area present in its upper eye orbit which plays a part in a reference system for counterillumination adjustments. This unique feature also acts as a spectral filter for camouflage breaking. Rental specializations amongst these sharks aid in prey detection and help reflect lifestyle differences between very similar species of deep sea sharks such as ''[[Velvet belly lanternshark|Etmopterus spinax]]'' and ''[[Slendertail lanternshark|Etmopterus molleri]]''.<ref name=":2" /> These bioluminescent sharks possess higher rod densities, which might provide them with improved temporal resolution - particularly useful for bioluminescent communication during social interactions.

Luminous ''Etmopterus'' sharks swim faster than other deep sea species. Different swimming speeds and tail beat frequencies have been observed amongst these deep sea species via high definition digital imaging coupled with large fish traps deployed simultaneously to these video systems. Also, using these same cameras and traps, length values were measured using a special software - [[MATLAB|MatLab]] - between 2009 and 2012.<ref>{{Cite journal |last1=Pinte |first1=Nicolas |last2=Parisot |first2=Pascaline |last3=Martin |first3=Ulrich |last4=Zintzen |first4=Vincent |last5=De Vleeschouwer |first5=Christophe |last6=Roberts |first6=Clive D. |last7=Mallefet |first7=Jérôme |date=2020-02-01 |title=Ecological features and swimming capabilities of deep-sea sharks from New Zealand |url=https://www.sciencedirect.com/science/article/pii/S0967063719303334 |journal=Deep Sea Research Part I: Oceanographic Research Papers |language=en |volume=156 |pages=103187 |doi=10.1016/j.dsr.2019.103187 |issn=0967-0637}}</ref> Little to no observed size change was recorded with depth.

==References==
{{reflist}}
* {{FishBase | genus = Etmopterus | species = splendidus | month = July | year = 2006}}
* [[Leonard Compagno|Compagno]], Dando, & Fowler, ''Sharks of the World'', Princeton University Press, New Jersey 2005 {{ISBN|978-0-691-12072-0}}

{{Selachimorpha|D.}}
{{Taxonbar|from=Q1038834}}

{{DEFAULTSORT:Splendid lanternshark}}
[[Category:Etmopterus]]
[[Category:Fish described in 1988]]