Wikipedia

User:Opeongo2011/sandbox

Term Project: Willa Neilsen and Emily Palmer

Note: We added to an existing page that included; the first paragraph, before Taxonomy, and the species description box. All sub-titled sections were added by us.

Southern lanternshark
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Subdivision: Selachimorpha
Order: Squaliformes
Family: Etmopteridae
Genus: Etmopterus
Species:
E. granulosus
Binomial name
Etmopterus granulosus
(Günther, 1880)
Range of the southern lanternshark (in blue)
Synonyms

Etmopterus baxteri Garrick, 1957 [2]

The southern lanternshark (Etmopterus granulosus) is a shark of the family Etmopteridae found in the southeast Pacific between latitudes 29°S and 59°S, at depths of between 220 and 1,460 m.[3] This species has been found off Northland, off the Chatham Islands, on the Campbell Plateau, all in New Zealand waters.[4] Its length is up to 60 cm.[3] Reproduction is ovoviviparous, with 10 to 13 pups in a litter, length at birth about 18 cm.[3][2] They exhibit bioluminescence.[5]

Parasites of the southern lanternshark, studied off Chile, include Monogeneans, Digeneans, Cestodes, Nematodes, and Copepodes.[6]

In June 2018 the New Zealand Department of Conservation classified E. granulosus as "Not Threatened" with the qualifier "Secure Overseas" under the New Zealand Threat Classification System.[7]

Taxonomy edit

The southern lanternshark (Etmopterus granulosus) and the giant lanternshark (Etmopterus baxteri) are now considered conspecifics thanks to DNA sequencing.[8][9] They had previously been considered separate species based on the assumption that E. granulosus was confined to the regions surrounding South America while E. baxteri was thought to occupy a range around New Zealand and Australia.[10]

This is a relatively large species of lanternshark, which is part of the Etmopterus spinax clade of the family Etmopteridae.[9] Etmopteridae is one of only three families containing species of bioluminescent sharks, Etmopteridae, Dalatiidae, and Somniosidae.[11][12]

Distribution edit

Although patchy, the distribution of the Southern Lanternshark is widespread throughout the Southern Hemisphere. They are thought to have a circum-Antarctic distribution. [13] Populations have been reported from the Southwest (Argentina, Falkland Islands) and Southeast Atlantic Ocean (South Africa, Angola), Western (southern Madagascar Ridge, Amsterdam Island) and Eastern (southeast Australia) Indian Ocean, and Southwest (Tasman Sea, New Zealand) and Southeast (Chile) Pacific Ocean. [14]

Actual population sizes and trends for this species are unknown in most of its range, with most information coming from New Zealand and Australia. [15]

Reproduction edit

The Southern Lanternshark has been found to reach maximum lengths of 88cm, however size at maturity varies according to region. Generally, males mature at 46-68 cm total length, and females mature at 62-69 cm total length. Age at maturity has been estimated as 20 and 30 years for males and females, respectively. [14]

Aspects of the life history of E. granulosus could imply that mate availability is a limiting factor to this species reproduction. Monogamy is common in populations, with a female skewed sex ratio and segregation by size class and sex being contributing factors by limiting access to mates. [16] Another factor that may contribute to monogamy among populations of the Southern Lanternshark may be asynchronous reproduction. It may be difficult to come across a viable mate if the timing and location of mating in this species is unpredictable.

This unpredictable reproductive cycle may be related to the consistent environment of the deep sea, as they do not see the same seasonal changes that species inhabiting surface waters experience. [16] This irregularity in reproductive patterns may be beneficial due to the fact that larger females of this species do not have the best fecundity. The absence of a specific mating and reproductive season allows individuals to do so year-round. It also means that regular fishing of this species will not result in a reduction in population sizes. [16]

E. granulosus, although not verified, is generally classified as having lecithotrophic viviparous, as well as asynchronous, reproduction, and a confirmed reproductive cycle has not been established. [17]

Feeding edit

The diet of the southern lanternshark has not been studied in detail. In New Zealand and Australia, it has been reported that their diet consists mostly of fish, including orange roughy and squid. More specifically, the diet of the southern lanternshark is made up mostly of teleosts. Cephalopod prey is also important and crustaceans are a minor component. [18]

The importance of teleost prey in the diet seems to increase with the total length of the individual, while crustaceans are more important in the diet of smaller individuals. [18]

Bioluminescence edit

Light Generation and Control: edit

 ** An image of E. granulosus bioluminescent pattern and photophore structure can be found in Figure 2, panel E of Mallefet et al. (2021)[19]. Note: the image could not be uploaded because of copy-write laws **

Etmopterids, such as E. granulosus, have specialized cells called photophores which produce a blue coloured bioluminescent light, rather than harbouring bioluminescent symbionts. However, the mechanisms of bioluminescence among elasmobranchs, including Etmopterids, is still poorly understood although recent studies (as of 2022) have begun to identify some compounds which influence the bioluminescence of Etmopterids.

 
Structure of of the luciferin coelenterazine

In a controlled study, tissue samples from three Etmopteridae species produced a bioluminescent reaction when exposed to the luciferin coelenterazine[12], which suggests that the coelenterazine luciferin-luciferase system is a mechanism of bioluminescence among Etmopterids. However, some species (E. spinax) tissues have not reacted to coelenterazine and it is still unclear if the Etmopteridae species that did react produce coelenterazine metabolically or obtain it from their diet. [20] [12]

The bioluminescence of Etmopterids also appears to be at least partially hormone controlled.[19] Tissue samples from E. granulosus displayed an increase in the intensity of the bioluminescent light they produced when exposed to the hormone melatonin at a concentration of 10-6 mol/L. The light intensity produced by E. granulosus photophores decreased when exposed to a 10-6 mol/L treatment of alpha-melanocyte-stimulating hormone.

 
Diagram of how bioluminescent compounds (luciferins) are transferred in conjunction with the carbon cycle.

Photophore Structure and Distribution: edit

Etmopterids tend too have large and complex photophores although the exact structure may differ among species. E. granulosus’ photophores appear typical of Etmopterids; having three photocytes positioned underneath an iris-like structure, which is cupped by a pigmented sheath, all underneath a single lens cell.[19] The photophores are part of the epidermis and are distributed amongst placoid scales. The highest concentration of photophores were on the ventral side, as well as below the pectoral fins and along the bottom side of the tail, however their distribution is heterogeneous and creates a species specific ‘pattern’ of bioluminescence.[19]

Functional Uses: edit

The highest concentration of photophores are on the ventral side of E. granulosus which indicated that their bioluminescence functions primarily in camouflage through counter-illumination.[19] This is a common use of bioluminescence in the twilight zone as there are no structures to hide from predators, counter-illumination ‘masks’ the shark's shadow so it is difficult for larger predators below to see them.  

The species within the Etmopteridae family have undergone extensive sympatric speciation and the observations of species specific bioluminescent patterns, have led to the hypothesis that these patterns, often referred to as flank markings, are used for conspecific recognition and have contributed to the reproductive isolation of species. [19][21]

References edit

  1. ^ Finucci, B.; Lamilla, J. (2018). "Etmopterus granulosus". IUCN Red List of Threatened Species. 2018: e.T116856245A3120311. doi:10.2305/IUCN.UK.2018-2.RLTS.T116856245A3120311.en. Retrieved 18 November 2021.
  2. ^ a b Weigmann, S. (2016): Annotated checklist of the living sharks, batoids and chimaeras (Chondrichthyes) of the world, with a focus on biogeographical diversity. Journal of Fish Biology, 88 (3): 837–1037.
  3. ^ a b c Froese, Rainer; Pauly, Daniel (eds.) (2017). "Etmopterus granulosus" in FishBase. June 2017 version.
  4. ^ Roberts, Clive; Stewart, A. L.; Struthers, Carl D.; Barker, Jeremy; Kortet, Salme; Freeborn, Michelle (2015). The fishes of New Zealand. Vol. 2. Wellington, New Zealand: Te Papa Press. p. 142. ISBN 9780994104168. OCLC 908128805.
  5. ^ "Glow-in-the-dark sharks found off New Zealand coast". BBC News. 3 March 2021. Retrieved 6 March 2021.
  6. ^ Espínola-Novelo, Juan F.; Escribano, Rubén; Oliva, Marcelo E. (2018). "Metazoan parasite communities of two deep-sea elasmobranchs: the southern lanternshark, Etmopterus granulosus, and the largenose catshark, Apristurus nasutus, in the Southeastern Pacific Ocean". Parasite. 25: 53. doi:10.1051/parasite/2018054. ISSN 1776-1042. PMC 6244290. PMID 30457552.  
  7. ^ Duffy, Clinton A. J.; Francis, Malcolm; Dunn, M. R.; Finucci, Brit; Ford, Richard; Hitchmough, Rod; Rolfe, Jeremy (2018). Conservation status of New Zealand chondrichthyans (chimaeras, sharks and rays), 2016 (PDF). Wellington, New Zealand: Department of Conservation. p. 10. ISBN 9781988514628. OCLC 1042901090.
  8. ^ Straube, Nicolas; Kriwet, Jürgen; Schliewen, Ulrich Kurt (2010). "Cryptic diversity and species assignment of large lantern sharks of the Etmopterus spinax clade from the Southern Hemisphere (Squaliformes, Etmopteridae): Phylo- and population genetics of etmopterid deep-sea sharks". Zoologica Scripta. 40 (1): 61–75. doi:10.1111/j.1463-6409.2010.00455.x.
  9. ^ a b Straube, Nicolas; Leslie, Robin W.; Clerkin, Paul J.; Ebert, David A.; Rochel, Elisabeth; Corrigan, Shannon; Li, Chenhong; Naylor, Gavin J.P. (2015). "On the occurrence of the Southern Lanternshark, Etmopterus granulosus , off South Africa, with comments on the validity of E. compagnoi". Deep Sea Research Part II: Topical Studies in Oceanography. 115: 11–17. doi:10.1016/j.dsr2.2014.04.004.
  10. ^ Straube, Nicolas; Schliewen, Ulrich; Kriwet, Jürgen (2008). "Dental structure of the Giant lantern shark Etmopterus baxteri (Chondrichthyes: Squaliformes) and its taxonomic implications". Environmental Biology of Fishes. 82 (2): 133–141. doi:10.1007/s10641-007-9264-z. ISSN 0378-1909.
  11. ^ Straube, Nicolas; Iglésias, Samuel P.; Sellos, Daniel Y.; Kriwet, Jürgen; Schliewen, Ulrich K. (2010). "Molecular phylogeny and node time estimation of bioluminescent Lantern Sharks (Elasmobranchii: Etmopteridae)". Molecular Phylogenetics and Evolution. 56 (3): 905–917. doi:10.1016/j.ympev.2010.04.042.
  12. ^ a b c Mizuno, Gaku; Yano, Daichi; Paitio, José; Endo, Hiromitsu; Oba, Yuichi (2021). "Etmopterus lantern sharks use coelenterazine as the substrate for their luciferin-luciferase bioluminescence system". Biochemical and Biophysical Research Communications. 577: 139–145. doi:10.1016/j.bbrc.2021.09.007.
  13. ^ Straube, Nicolas; Leslie, Robin W.; Clerkin, Paul J.; Ebert, David A.; Rochel, Elisabeth; Corrigan, Shannon; Li, Chenhong; Naylor, Gavin J. P. (2015-05-01). "On the occurrence of the Southern Lanternshark, Etmopterus granulosus, off South Africa, with comments on the validity of E. compagnoi". Deep Sea Research Part II: Topical Studies in Oceanography. Biology of Deep-Water Chondrichthyans. 115: 11–17. doi:10.1016/j.dsr2.2014.04.004. ISSN 0967-0645.
  14. ^ a b IUCN (2017-07-02). "Etmopterus granulosus: Finucci, B. & Lamilla, J.: The IUCN Red List of Threatened Species 2018: e.T116856245A3120311". doi:10.2305/iucn.uk.2018-2.rlts.t116856245a3120311.en. {{cite journal}}: Cite journal requires |journal= (help)
  15. ^ Irvine1 Stevens2, Sarah1 John2 (1 January 2002). "Hermaphroditism in The Southern Lantern Shark, Etmopterus granulosus". Deep Sea Biology – via ResearchGate.{{cite journal}}: CS1 maint: numeric names: authors list (link)
  16. ^ a b c Nehmens, Melissa C.; Feldheim, Kevin A.; Ebert, David A. (2020-08-28). "Understanding what we cannot see: a genetic approach to the mating system of the Southern Lanternshark, Etmopterus granulosus". Marine Biology. 167 (9): 139. doi:10.1007/s00227-020-03751-5. ISSN 1432-1793.
  17. ^ "The Life History of the Southern Lanternshark, Etmopterus granulosus , from the Southwestern Indian Ocean - ProQuest". www.proquest.com. Retrieved 2022-04-08.
  18. ^ a b Hallett, Chris S.; Daley, Ross K. (2011-01-01). "Feeding ecology of the southern lanternshark (Etmopterus baxteri) and the brown lanternshark (E. unicolor) off southeastern Australia". ICES Journal of Marine Science. 68 (1): 157–165. doi:10.1093/icesjms/fsq143. ISSN 1054-3139.
  19. ^ a b c d e f Mallefet, Jérôme; Stevens, Darren W.; Duchatelet, Laurent (2021). "Bioluminescence of the Largest Luminous Vertebrate, the Kitefin Shark, Dalatias licha: First Insights and Comparative Aspects". Frontiers in Marine Science. 8: 633582. doi:10.3389/fmars.2021.633582. ISSN 2296-7745.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  20. ^ Bessho-Uehara, Manabu; Huang, Wentao; Patry, Wyatt L.; Browne, William E.; Weng, Jing-Ke; Haddock, Steven H.D. (2020). "Evidence for de novo Biosynthesis of the Luminous Substrate Coelenterazine in Ctenophores". iScience. 23 (12): 101859. doi:10.1016/j.isci.2020.101859. PMC 7756133. PMID 33376974.{{cite journal}}: CS1 maint: PMC format (link)
  21. ^ Claes, Julien M.; Nilsson, Dan-Eric; Mallefet, Jérôme; Straube, Nicolas (2015). "The presence of lateral photophores correlates with increased speciation in deep-sea bioluminescent sharks". Royal Society Open Science. 2 (7): 150219. doi:10.1098/rsos.150219. ISSN 2054-5703. PMC 4632593. PMID 26587280.{{cite journal}}: CS1 maint: PMC format (link)


Category:Etmopterus Category:Ovoviviparous fish Category:Fish described in 1880 Category:Taxa named by Albert Günther

 

This shark-related article is a stub. You can help Wikipedia by expanding it.

Retrieved from "https://en.wikipedia.org/w/index.php?title=User:Opeongo2011/sandbox&oldid=1081748198"