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{{short description|Species of cephalopod}}
{{Redirect|Nautilus pompilius|the Russian rock band|Nautilus Pompilius (band)}}
{{Speciesbox
{{Speciesbox
| fossil_range = [[Early Pleistocene]] to [[Holocene|Recent]]
| name = Chambered Nautilus
| image = Nautilus_side.jpg
| image = Nautilus_side.jpg
| image_caption =
| status = VU
| status = VU
| status_system = IUCN3.1
| status_system = IUCN3.1
Line 8: Line 11:
| genus = Nautilus
| genus = Nautilus
| species = pompilius
| species = pompilius
| authority = [[Carl Linnaeus|Linnaeus]], [[10th edition of Systema Naturae|1758]]
| authority =
| synonyms = *''Nautilus repertus''<br><small>[[Tom Iredale|Iredale]], 1944</small>
}}<!-- EDIT BELOW THIS LINE -->
| subdivision_ranks = Subspecies
| subdivision = *''Nautilus pompilius pompilius''<br><small>[[Carl Linnaeus|Linnaeus]], [[10th edition of Systema Naturae|1758]]</small>
*''Nautilus pompilius suluensis''<br><small>[[Tadashige Habe|Habe]] & [[Takashi Okutani|Okutani]], 1988</small>
}}


The '''chambered nautilus''', '''''Nautilus pompilius''''', also called the '''pearly nautilus''', is the best-known [[species]] of [[nautilus]]. The shell, when cut away, reveals a lining of lustrous [[nacre]] and displays a nearly perfect [[logarithmic spiral|equiangular spiral]], although it is not a [[golden spiral]]. The shell exhibits [[countershading]], being light on the bottom and dark on top. This is to help avoid predators, because when seen from above, it blends in with the darkness of the sea, and when seen from below, it blends in with the light coming from above.
= Chambered Nautilus =


The range of the chambered nautilus encompasses much of the south Pacific; It has been found near reefs and on the seafloor off of the coasts of Australia, Japan, and Micronesia.<ref name=":0" />
== Summary ==
The [[chambered nautilus]] is a member of the class [[Cephalopod|Cephalopoda]] because of its complex brain, shell and large number of [[Tentacle|tentacles]].<ref name=":0">Bonnaud, L., C. Ozouf-Costaz, and R. Boucher-Rodoni. 2004. A molecular and karyological approach to the taxonomy of Nautilus. Comptes Rendus Biologies 327:133–138.</ref> Their external [[Seashell|shell]] provides protection and buoyancy while also separating the species from other common cephalopods ([[squid]], [[Octopus|octopuses]], [[cuttlefish]]).<ref>Jereb, P. 2005. Chambered nautiluses. Page FAO Species Catalogue for Fishery Purposes No. 4, Vol. 1.</ref> This protection comes in the form of [[countershading]], which makes it easy to hide from predators.<ref name=":1">Ward, P. D. 1987. The Natural History of Nautilus. Allen and Unwin, Winchester, MA. </ref> Unfortunately, this [[countershading]] is also the reason why chambered nautiluses are hunted by humans (their beautiful shells are [[Harvest|harvested]] for use in [[Jewellery|jewelry]]). This [[overfishing]] became so extreme that, in 2016, chambered nautiluses were moved to [[CITES Appendix II]], which limits [[international trade]], and they were later recognized as a [[threatened species]] under the [[Endangered Species Act]]. <ref>{{Cite web|url=https://www.fws.gov/international/cites/index.html|title=CITES|website=www.fws.gov|access-date=2020-04-19}}</ref>


The eyes of the chambered nautilus, like those of all ''Nautilus'' species, are more primitive than those of most other [[cephalopod]]s; the eye has no lens and thus is comparable to a [[pinhole camera]]. The species has about 90 [[Cirrus (biology)|cirri]] (referred to as "tentacles", see {{section link|Nautilus|Cirri}}) that do not have suckers, differing significantly from the limbs of [[coleoid]]s. Chambered nautiluses, again like all members of the genus, have a pair of [[rhinophore]]s located near each eye which detect chemicals, and use [[olfaction]] and [[chemotaxis]] to find their food.<ref>{{Cite journal|last=Basil|first=Jennifer A.|display-authors=et al|title=Three-dimensional odor tracking by Nautilus pompilius|url=http://jeb.biologists.org/content/jexbio/203/9/1409.full.pdf|journal=Journal of Experimental Biology|volume=203|issue=9}}</ref>{{citation needed lead|date=January 2012}}
== Status and Conservation with ESA history ==
Chambered Nautiluses are targeted for their shells, which are traded throughout the globe for their value as collectibles. This, combined with overfishing, [[Habitat destruction|habitat degradation]] and [[Global warming|climate change]], has led to the chambered nautilus being recognized as an [[International Union for Conservation of Nature|IUCN]] “[[Vulnerable species|vulnerable]]” species in 2016. However, in 2017, the [[Presidency of Donald Trump|Trump administration]] delayed necessary protections which would prevent [[Import|imports]] of this [https://www.biologicaldiversity.org/news/press_releases/2018/chambered-nautilus-09-27-2018.php species’ shells] (see: [[Center for Biological Diversity]] in "External Links"). This is likely a combination of the US Fisheries Service choosing not to close the nautilus import market, as well as a lack of understanding on the species’ [[biology]] and their response to fishery pressure. It was not until 2018 that the chambered nautilus was recognized as a [[threatened species]] under the [[Endangered Species Act of 1973|Endangered Species Act]]. A five-year review has not been conducted, as the chambered nautilus has only been listed for two years. As a result, there have been no listing changes, as the nautilus is still recognized as “threatened.”


The oldest fossils of the species are known from [[Early Pleistocene]] sediments deposited off the coast of [[Luzon]] in the [[Philippines]].<ref name="Ryoji2008">{{cite journal |last1=Ryoji |first1=W. |year=2008 |title= First discovery of fossil ''Nautilus pompilius'' (Nautilidae, Cephalopoda) from Pangasinan, northwestern Philippines |journal= Paleontological Research |volume=12 |issue=1 |pages=89–95 |doi= 10.2517/1342-8144(2008)12[89:FDOFNP]2.0.CO;2|display-authors=etal}}</ref>
The practice of shell harvesting largely occurs in [[Indonesia]] and the [[Philippines]]; however, there is currently a push for more [[Environmental law|environmental-law]] enforcement.<ref>LEMIS. 2016. All import and exports of Nautilus sp. from January 1, 1999 to April 31, 2016. U.S. Fish and Wildlife-Office of Law Enforcement, Arlington, Virginia.</ref> The passing of these environmental laws promises a reduction in the unsustainable harvest of nautilus shells. This is especially important since the chambered nautilus exhibits a slow [[growth rate]] and low [[Reproduction|reproductive]] output. <ref>Saunders, W. B. 1983. Natural rates of growth and longevity of Nautilus belauensis. Paleobiology: 280–288.</ref>
[[File:The_first_and_oldest_fossil_of_Chambered_Nautilus_displayed_at_Philippine_National_Museum.jpg|thumb|The first and oldest fossil of [[Chambered Nautilus]] displayed at the [[National Museum of the Philippines|Philippine National Museum]].]]
Although once thought to be a living fossil, the chambered nautilus is now considered taxonomically very different from ancient [[Ammonoidea|ammonites]], and the recent fossil record surrounding the species shows more genetic diversity among nautiluses now than has been found since the extinction of the dinosaurs.<ref name=":0">{{Cite news|url=https://www.newscientist.com/article/mg19826501-700-nautilus-chambers-of-secrets/|title=Nautilus: Chambers of secrets|last=Ward|first=Peter|newspaper=New Scientist|language=en-US|access-date=2016-12-13}}</ref> Indeed, the taxon of the chambered nautilus, ''Nautilus pompilius'' is actually a grouping of tens of different species of nautilus under one name.<ref name=":0" />


All nautilus species are threatened due to [[overfishing]] for their shell, which primarily is used for jewelry and other ornamental artifacts.<ref>{{cite news |last=Broad |first=William |title=Loving the Chambered Nautilus to Death |url=https://www.nytimes.com/2011/10/25/science/25nautilus.html |accessdate=24 October 2011 |newspaper=The New York Times |date=24 October 2011 |archiveurl=https://web.archive.org/web/20111027232842/http://www.nytimes.com/2011/10/25/science/25nautilus.html?_r=1 |archivedate=27 October 2011 |url-status=dead }}</ref> In 2016, they were moved to [[CITES Appendix II]], which restricts international trade, and later the chambered nautilus was recognized as a threatened species under the [[Endangered Species Act]].<ref>{{cite web| title=Chambered Nautilus – Conservation & Management | url=https://www.fisheries.noaa.gov/species/chambered-nautilus#conservation-management | publisher=[[NOAA]] Fisheries | accessdate=5 October 2019 }}</ref>
== Description ==
The chambered nautilus is considered [[primitive]] when compared to other [[Cephalopod|cephalopods]], such as the [[octopus]] and [[squid]]. One is because of its shell, which is composed of many “[[chambers]],” which increase in number as the [[organism]] [[Mature|matures]] (they have 4 chambers when newly-hatched; up to 40 when fully mature).<ref>Shapiro, E. A., and W. B. Saunders. 2010. Nautilus Shell Hydrostatics. Pages 527–545 in W. B. Saunders and N. H. Landman, editors. Nautilus. Springer Netherlands.</ref> These chambers allow the organism to occupy more space as they grow throughout their [[Life expectancy|lifespan]], which is useful because their shells can reach [[Diameter|diameters]] up to 25 [[Centimetre|centimeters]] when they become fully mature.<ref name=":1" /> Their shells, while also offering [[buoyancy]], exhibit [[countershading]], meaning they have a much lighter [[tone]] on the [[inferior]] side.<ref name=":0" /> This increases the difficulty for predators to find and [[Consumption|consume]] the [[Cephalopods in popular culture|nautiluses]], as the shading allows them to effectively blend in with their [[environment]]. Unfortunately, their ability to countershade is also the reason why the chambered nautilus is targeted by humans, as there is a high [[economic value]] for their beautiful shells for use in [[Jewellery|jewelry]]. <ref>Aguiar, J. 2000. Nautilus in the Pacific. Tentacle: 15–16.</ref>


== Life cycle ==
Another reason chambered nautiluses are considered [[primitive]] is because of their [[brain]], which lacks the [[neural structures]] found in other cephalopods that support [[learning]].<ref name=":2">Crook, R. J., and J. A. Basil. 2013. Flexible Spatial Orientation and Navigational Strategies in Chambered Nautilus. Ethology 119:77–85.</ref> However, lab [[Experiment|experiments]] have [[data]] that suggest nautiluses are capable of [[Spatial memory|spatial learning]] and [[Strategy|navigational strategies]], which is important since most of their time is spent in deep, dark water. <ref name=":2" />
Because of their oceanic habitat, studies of their life cycle have primarily been based on captive animals and their eggs have never been seen in the wild.<ref name=MontereyBayAq2018>{{cite web | title=The Chronicles of Nautilus | url=https://www.montereybayaquarium.org/members/shorelines/shorelines-spring-2018/online-exclusive | publisher=Monterey Bay Aquarium | date=Spring 2018 | accessdate=5 October 2019 }}</ref> Although nautilus have been kept at [[public aquarium]]s since the 1950s, the chambered nautilus was first bred in captivity at the [[Waikiki Aquarium]] in 1995 (a couple of other nautilus species had been bred earlier) and captive breeding remains a rare event even today.<ref>{{cite book | author=Norman, M. | year=2000 | title=Cephalopods – A World Guide | pages=24-29 | publisher=ConchBooks }}</ref> Unlike most cephalopods, the nautilus lacks a larval stage. The eggs are laid in crevices or between corals by the female. The nautilus shell of the young develop inside their eggs and breach the top of the egg before the nautilus fully emerges. Depending on water temperature, the eggs hatch after between 9 and 15 months.<ref name=MontereyBayAq2018/> In 2017, it was bred at [[Monterey Bay Aquarium]], which managed — possibly for the first time ever — to film the young emerging from the egg.<ref>{{cite news | title=Mysterious nautilus hatch at Monterey Bay Aquarium | url=https://www.youtube.com/watch?v=hud5kOW5OW8 | publisher=KSBW Action News 8, official YouTube channel | date=13 December 2017 | accessdate=5 October 2019 }}</ref> Like other nautilus but unlike most other cephalopods, chambered nautilus are relatively long-lived and only reach maturity when about 5 years old.<ref name=MontereyBayAq2018/>


== Behavior ==
== Diet ==
As a carnivore, it feeds on both underwater carrion and detritus, as well as living shellfish and crab.<ref name=":022">{{Cite book|title=In Search Of Nautilus|last=Ward|first=Peter|publisher=Simon and Schuster|year=1988|isbn=0-671-61951-9|location=New York|pages=[https://archive.org/details/insearchofnautil00ward/page/72 72]|quote=|via=|url-access=registration|url=https://archive.org/details/insearchofnautil00ward/page/72}}</ref> Mainly scavengers, chambered nautiluses have been described as eating "anything that smells".<ref name=":022"/> This food is stored in a stomach-like organ known as a crop, which can store food for a great deal of time without it denaturing.<ref name=":022"/>
The chambered nautilus tends to move to deeper waters (1000-1500 feet) during the daytime, in an effort to avoid [[predation]]. However, at night they ascend to [[Coral reef|coral reefs]] (about 300 feet deep) to hunt for prey.<ref name=":3">Kier, W. M. 2010. The Functional Morphology of the Tentacle Musculature of Nautilus pompilius. Pages 257–269 in W. B. Saunders and N. H. Landman, editors. Nautilus Springer Netherlands.</ref> Because of this technique, their [[diet]] consists of [[Organism|organisms]] that dwell in shallow waters, such as [[Fish|small fish]], [[shrimp]] and [[Crab|crabs]]. One of the reasons they hunt at night is because it makes their prey less aware they are being [[Hunting|hunted]].<ref>Ward, P., F. Dooley, and G. J. Barord. 2016. Nautilus: biology, systematics, and paleobiology as viewed from 2015. Swiss Journal of Palaeontology 135: 169–185.</ref> However, this makes it slightly more difficult for the chambered nautilus to [[detect]] its prey, but their tentacles have [[chemosensors]] for this sole purpose<ref>Barord, G. J., F. Dooley, A. Dunstan, A. Ilano, K. N. Keister, H. Neumeister, T. Preuss, S. Schoepfer, and P. D. Ward. 2014. Comparative Population Assessments of Nautilus sp. in the Philippines, Australia, Fiji, and American Samoa Using Baited Remote Underwater Video Systems. DOI: 9:e100799.</ref>. They can detect the [[Odor|scent]] of [[prey]] from a long distance, making it easy for the nautilus to navigate its way to its prey. It is important to note that there is no [[scientific evidence]] for chambered nautiluses hunting in [[Group|groups]].


=== Life Cycles ===
==Subspecies==
The chambered nautilus’ [[life cycle]] is relatively long compared to other [[Cephalopod|cephalopods]]. It is not uncommon for this nautilus to live at least 15-20 years. <ref>Collins, D., and P. D. Ward. 2010. Adolescent Growth and Maturity in Nautilus. Pages 421–432 in W. B. Saunders and N. H. Landman, editors. Nautilus Springer Netherlands.</ref>However, they do experience a late [[maturity]], not laying a small [[Broodiness|brood]] of eggs until they are about 10-12 years of age.<ref>Landman, N. H., and J. K. Cochran. 2010. Growth and Longevity of Nautilus. Pages 401–420in W. B. Saunders and N. H. Landman, editors. Nautilus Springer Netherlands.</ref> These eggs also require a year-long [[incubation]] period. During this time, offspring are [[vulnerable]] to predation, which results in an extremely-low [[Reproduction|reproductive output]].


Two [[subspecies]] of ''N. pompilius'' have been described: ''N. p. pompilius'' and ''N. p. suluensis''
=== Reproduction ===
Although there is not a lot of [[scientific literature]] on the chambered nautilus’ [[Biological life cycle|reproductive cycle]], there are some [[Hypothesis|hypotheses]] for their [[Mating|mating habits]]. One is that males [[transfer]] [[sperm]] to females through a [[spermatophore]], which contains a mass of [[sperm]] within a [[Coating|protective coating]].<ref>Arnold, J. M. 2010. Reproduction and Embryology of Nautilus. Pages 353–37 2in W. B. Saunders and N. H. Landman, editors. Nautilus Springer Netherlands.</ref> This [[Adherens junction|adheres]] to the female nautilus’ [[Mantle cell lymphoma|mantle wall]], where the coating can then [[dissolve]] to [[release]] the sperm. Following this [[Fertilisation|internal fertilization process]], the eggs released require a year-long [[incubation period]]. This, combined with the late-maturity rate of chambered nautiluses, is one of the reasons why the species is [[declining]] dramatically through [[Human-induced climate change|human-induced predation]].<ref name=":4">Haven, N. 1977. The reproductive biology of Nautilus pompilius in the Philippines. Marine Biology 42:177–184.</ref> Most of the nautiluses are harvested long before maturity, which prevents them from reproducing, therefore leaving less offspring each generation.


''N. p. pompilius'' is by far the most common and widespread of all nautiluses. It is sometimes called the '''emperor nautilus''' due to its [[cephalopod size|large size]]. The distribution of ''N. p. pompilius'' covers the [[Andaman Sea]] east to [[Fiji]] and southern [[Japan]] south to the [[Great Barrier Reef]]. Exceptionally large specimens with shell diameters up to {{convert|254|mm|in|abbr=on}}<ref>Pisor, D.L. (2008). ''[[Registry of World Record Size Shells]]''. Fifth edition. ConchBooks, Hackenheim. 207&nbsp;pp. {{ISBN|0615194753}}.</ref> have been recorded from [[Indonesia]] and northern [[Australia]]. This giant form was described as '''''Nautilus repertus''''', but most scientists do not consider it a separate species.
=== Locomotion ===
[[Locomotion]] is achieved through [[Propulsion|jet-like propulsions]] where the nautilus pulls in water into its [[Seashell|shell’s mantle cavity]] and releases it back through the [[Siphon (mollusc)|muscular siphon]] beneath its [[Tentacle|tentacles]].<ref>Saunders, W. B., and P. D. Ward. 2010. Ecology, Distribution, and Population Characteristics of Nautilus. Pages 137–162 in W. B. Saunders and N. H. Landman, editors. Nautilus. Springer Netherlands.</ref> This [[Siphon (mollusc)|siphon]] can not only direct the water in multiple directions, providing the nautilus with easy [[maneuverability]], but it also keeps the organism [[Body relative direction|upright]] in the water.


''N. p. suluensis'' is a much smaller animal, restricted to the [[Sulu Sea]] in the southwestern [[Philippines]], after which it is named. The [[cephalopod size|largest known specimen]] measured 160&nbsp;mm in shell diameter.<ref>[http://www.conchology.be/?t=68&u=626793&g=1e1012d7a54ee03e9e40db969f89b3c8&q=a84eff41a380577a0fc6c2eada7d1fd4 ''Nautilus pompilius suluensis'' ID:626793]. Shell Encyclopedia, Conchology, Inc.</ref>
== Habitat and Distribution ==
Chambered nautiluses, in an effort to avoid predation, are commonly found in deep water during the daytime. At night, they [[Migration|migrate]] [[Vertical|vertically]] to [[Shallow|shallower]] waters to hunt for prey.<ref name=":3" /> The chambered nautilus is mostly found on the [[Coast|coastal]] areas of the [[Pacific Ocean|Pacific]] and [[Indian Ocean|Indian Oceans]], specifically near [[Coral reef|coral reefs]]. [[Indonesia]] and the [[Philippines]] are the sites with the most-common occurrences.<ref name=":4" />
[[File:Contribution_to_the_natural_history_of_the_pearly_nautilus_(1902)_(20682450302).jpg|thumb|Distribution of Chambered Nautilus]]
The chambered nautilus’ first [[Population estimates|population estimate]] was made in 2010, which suggested that there were between 2344 and 4467 [[Individual|individuals]] present. This number has declined in recent years as a result of [[overfishing]]. The current estimates predict that there are between 844 and 2404 individuals present.<ref name=":5">Dunstan, A, Bradshaw C.J.A., Marshall, J. (2011) Nautilus at Risk – Estimating Population Size and Demography of Nautilus pompilius. PLoS ONE 6(2):e16716.doi:10.1371/journal.pone.0016716.</ref> It is important to note that both population estimates were dominated by males (83:17). There is no evidence that their [[Geographic range limit|geographic range]] has changed as a result of overfishing, as most sightings occur in [[Indonesia]] and the [[Philippines]].<ref name=":5" />


== Shell geometry ==
In January 2020, [[NOAA Fisheries]] determined that it was not prudent to designate a [[critical habitat]] for the chambered nautilus. This decision was reached after a [[comprehensive]] review of [[scientific data]]. Also, since the chambered nautilus primarily occurs outside the [[jurisdiction]] of the [[United States]], there would not be a [[Significance|significant]] [[conservation]] value provided.
The chambered nautilus is often used as an example of the [[golden spiral]]. While nautiluses show logarithmic spirals, [http://www.sciencenews.org/articles/20050402/mathtrek.asp their ratios range] from about 1.24 to 1.43, with an average ratio of about 1.33 to 1. The golden spiral's ratio is 1.618. This is actually visible when the cut nautilus is [http://shallowsky.com/blog/science/fibonautilus.html inspected].


== References ==
== Shell function ==
The shell of the chambered nautilus fulfills the function of buoyancy, which allows the nautilus to dive or ascend at will, by controlling the density and volume of the liquid within its shell chambers.<ref name=":1">{{Cite book|title=In Search of Nautilus|last=Ward|first=Peter|publisher=Simon and Schuster|year=1988|isbn=0-671-61951-9|location=New York|pages=[https://archive.org/details/insearchofnautil00ward/page/160 160]|quote=|via=|url-access=registration|url=https://archive.org/details/insearchofnautil00ward/page/160}}</ref> This was found during research done in New Caledonia on nautiluses whose shell chamber fluid densities were tested at various depths, weeks apart.<ref name=":1" /> Generally speaking, chambered nautiluses inhabit a depth around 1000 feet, although further tests demonstrated that they can, and do, dive deeper.<ref name=":1" /> However, there are hazards associated with extreme depth for the nautilus: the shells of chambered nautiluses slowly fill with water at such depths, and they are only capable of withstanding depths up to 2000 feet before imploding due to pressure.<ref name=":1" />
<references />


The chambered nautilus inhabits different segments of the shell as it grows, continuously growing new, larger "cells" into which it moves its internal organs as it grows in maturity.<ref name=":1" /> All of the smaller chambers, once uninhabited, are used in the method described above to regulate depth.<ref name=":1" />
== External Links ==


== In literature and art ==
* NOAA ESA Complaint: https://www.fisheries.noaa.gov/resource/document/endangered-species-act-status-review-report-chambered-nautilus
<!-- This section is linked from [[Nautilus]] -->
* CITES Appendix II: https://www.fws.gov/international/cites/index.html
Nautilus shells were popular items in the Renaissance [[cabinet of curiosities]] and were often mounted by [[goldsmith]]s on a thin stem to make extravagant '''nautilus shell cups''', such as the [[Burghley Nef]], mainly intended as decorations rather than for use. Small natural history collections were common in mid-19th-century Victorian homes, and chambered nautilus shells were popular decorations.
* CoP17: https://www.fws.gov/international/cites/cop17/index.html

* Endangered Species Act: https://www.fws.gov/endangered/laws-policies/
The chambered nautilus is the title and subject of a poem by [[Oliver Wendell Holmes, Sr.|Oliver Wendell Holmes]], in which he admires the "ship of pearl" and the "silent toil/That spread his lustrous coil/Still, as the spiral grew/He left the past year's dwelling for the new." He finds in the mysterious life and death of the nautilus strong inspiration for his own life and spiritual growth. He concludes:
* Critical Habitat Determination: https://www.fisheries.noaa.gov/action/determination-designation-critical-habitat-chambered-nautilus

* Center for Biological Diversity: https://www.biologicaldiversity.org/news/press_releases/2018/chambered-nautilus-09-27-2018.php
<blockquote><poem>Build thee more stately mansions, O my soul,
As the swift seasons roll!
Leave thy low-vaulted past!
Let each new temple, nobler than the last,
Shut thee from heaven with a dome more vast,
Till thou at length art free,
Leaving thine outgrown shell by life's unresting sea!</poem></blockquote>

A painting by [[Andrew Wyeth]], entitled ''Chambered Nautilus'', shows a woman in a canopied bed; the composition and proportions of the bed and the window behind it mirror those of a chambered nautilus lying on a nearby table.

The popular [[Russia]]n [[rock band]] [[Nautilus Pompilius (band)|Nautilus Pompilius]] ({{lang-ru|Наутилус Помпилиус}}) is named after the species.

[[United States|American]] composer and commentator [[Deems Taylor]] wrote a cantata entitled The Chambered Nautilus in 1916.

<gallery widths="200px" heights="200px">
File:Milano - Castello sforzesco - Nautilus su argento cesellato - Germania, sec. XVI - Foto Giovanni Dall'Orto - 6-1-2007.jpg|16th-century [[Northern Mannerist]] nautilus cup
File:Nautilus shells to commemorate Horatio Nelson, at Monmouth Museum, Wales.JPG|Nautilus shells engraved to commemorate [[Horatio Nelson, 1st Viscount Nelson|Horatio Nelson]], displayed at [[Monmouth Museum]]
File:Nautilus pompilius (detail).jpg|thumb|A big nautilus<ref>{{cite web|publisher= [[The Walters Art Museum]]|url= http://art.thewalters.org/detail/16751|title= Nautilus Cup}}</ref>
File:NautilusCutawayLogarithmicSpiral.jpg|Cutaway of a nautilus shell showing the chambers
File:Nautilus shell.jpg|Empty nautilus shell, whole
File:Nautilus pompilius anatomy.jpg|Internal anatomy of ''Nautilus pompilius''
</gallery>

==References==
{{Reflist}}
* Norman, M. 2000. ''Cephalopods: A World Guide''. Hackenheim, ConchBooks, pp.&nbsp;30–31.
* {{cite book | author = Pisor, D. L. | year = 2005 | title = [[Registry of World Record Size Shells]] | edition = 4th | publisher = Snail's Pace Productions and ConchBooks | pages = 93}}
* Ward, Peter (1988) ''In Search Of Nautilus: Three Centuries of Scientific Adventures in the Deep Pacific to Capture a Prehistoric, Living Fossil.'' New York: Simon and Schuster, Print.
* Ward, Peter (2008) [https://www.newscientist.com/article/mg19826501-700-nautilus-chambers-of-secrets/ ''Chamber of Secrets.''] New Scientist, April 02 2008

==External links==
{{commons|Nautilus pompilius}}
{{Collier's Poster|Pearly nautilus}}
{{CephBase Species|1}}(''Nautilus pompilius pompilius'')
{{CephBase Species|4}}(''Nautilus pompilius suluensis'')

{{Taxonbar|from=Q872853}}

[[Category:Nautiluses]]
[[Category:Molluscs described in 1758]]
[[Category:Extant Pleistocene first appearances]]

Revision as of 19:12, 19 April 2020

"Nautilus pompilius" redirects here. For the Russian rock band, see Nautilus Pompilius (band).

Chambered nautilus
Temporal range: Early Pleistocene to Recent
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Subclass: Nautiloidea
Order: Nautilida
Family: Nautilidae
Genus: Nautilus
Species:
N. pompilius
Binomial name
Nautilus pompilius
Subspecies
Synonyms

The chambered nautilus, Nautilus pompilius, also called the pearly nautilus, is the best-known species of nautilus. The shell, when cut away, reveals a lining of lustrous nacre and displays a nearly perfect equiangular spiral, although it is not a golden spiral. The shell exhibits countershading, being light on the bottom and dark on top. This is to help avoid predators, because when seen from above, it blends in with the darkness of the sea, and when seen from below, it blends in with the light coming from above.

The range of the chambered nautilus encompasses much of the south Pacific; It has been found near reefs and on the seafloor off of the coasts of Australia, Japan, and Micronesia.[1]

The eyes of the chambered nautilus, like those of all Nautilus species, are more primitive than those of most other cephalopods; the eye has no lens and thus is comparable to a pinhole camera. The species has about 90 cirri (referred to as "tentacles", see Nautilus § Cirri) that do not have suckers, differing significantly from the limbs of coleoids. Chambered nautiluses, again like all members of the genus, have a pair of rhinophores located near each eye which detect chemicals, and use olfaction and chemotaxis to find their food.[2][not verified in body]

The oldest fossils of the species are known from Early Pleistocene sediments deposited off the coast of Luzon in the Philippines.[3]

The first and oldest fossil of Chambered Nautilus displayed at the Philippine National Museum.

Although once thought to be a living fossil, the chambered nautilus is now considered taxonomically very different from ancient ammonites, and the recent fossil record surrounding the species shows more genetic diversity among nautiluses now than has been found since the extinction of the dinosaurs.[1] Indeed, the taxon of the chambered nautilus, Nautilus pompilius is actually a grouping of tens of different species of nautilus under one name.[1]

All nautilus species are threatened due to overfishing for their shell, which primarily is used for jewelry and other ornamental artifacts.[4] In 2016, they were moved to CITES Appendix II, which restricts international trade, and later the chambered nautilus was recognized as a threatened species under the Endangered Species Act.[5]

Life cycle

Because of their oceanic habitat, studies of their life cycle have primarily been based on captive animals and their eggs have never been seen in the wild.[6] Although nautilus have been kept at public aquariums since the 1950s, the chambered nautilus was first bred in captivity at the Waikiki Aquarium in 1995 (a couple of other nautilus species had been bred earlier) and captive breeding remains a rare event even today.[7] Unlike most cephalopods, the nautilus lacks a larval stage. The eggs are laid in crevices or between corals by the female. The nautilus shell of the young develop inside their eggs and breach the top of the egg before the nautilus fully emerges. Depending on water temperature, the eggs hatch after between 9 and 15 months.[6] In 2017, it was bred at Monterey Bay Aquarium, which managed — possibly for the first time ever — to film the young emerging from the egg.[8] Like other nautilus but unlike most other cephalopods, chambered nautilus are relatively long-lived and only reach maturity when about 5 years old.[6]

Diet

As a carnivore, it feeds on both underwater carrion and detritus, as well as living shellfish and crab.[9] Mainly scavengers, chambered nautiluses have been described as eating "anything that smells".[9] This food is stored in a stomach-like organ known as a crop, which can store food for a great deal of time without it denaturing.[9]

Subspecies

Two subspecies of N. pompilius have been described: N. p. pompilius and N. p. suluensis

N. p. pompilius is by far the most common and widespread of all nautiluses. It is sometimes called the emperor nautilus due to its large size. The distribution of N. p. pompilius covers the Andaman Sea east to Fiji and southern Japan south to the Great Barrier Reef. Exceptionally large specimens with shell diameters up to 254 mm (10.0 in)[10] have been recorded from Indonesia and northern Australia. This giant form was described as Nautilus repertus, but most scientists do not consider it a separate species.

N. p. suluensis is a much smaller animal, restricted to the Sulu Sea in the southwestern Philippines, after which it is named. The largest known specimen measured 160 mm in shell diameter.[11]

Shell geometry

The chambered nautilus is often used as an example of the golden spiral. While nautiluses show logarithmic spirals, their ratios range from about 1.24 to 1.43, with an average ratio of about 1.33 to 1. The golden spiral's ratio is 1.618. This is actually visible when the cut nautilus is inspected.

Shell function

The shell of the chambered nautilus fulfills the function of buoyancy, which allows the nautilus to dive or ascend at will, by controlling the density and volume of the liquid within its shell chambers.[12] This was found during research done in New Caledonia on nautiluses whose shell chamber fluid densities were tested at various depths, weeks apart.[12] Generally speaking, chambered nautiluses inhabit a depth around 1000 feet, although further tests demonstrated that they can, and do, dive deeper.[12] However, there are hazards associated with extreme depth for the nautilus: the shells of chambered nautiluses slowly fill with water at such depths, and they are only capable of withstanding depths up to 2000 feet before imploding due to pressure.[12]

The chambered nautilus inhabits different segments of the shell as it grows, continuously growing new, larger "cells" into which it moves its internal organs as it grows in maturity.[12] All of the smaller chambers, once uninhabited, are used in the method described above to regulate depth.[12]

In literature and art

Nautilus shells were popular items in the Renaissance cabinet of curiosities and were often mounted by goldsmiths on a thin stem to make extravagant nautilus shell cups, such as the Burghley Nef, mainly intended as decorations rather than for use. Small natural history collections were common in mid-19th-century Victorian homes, and chambered nautilus shells were popular decorations.

The chambered nautilus is the title and subject of a poem by Oliver Wendell Holmes, in which he admires the "ship of pearl" and the "silent toil/That spread his lustrous coil/Still, as the spiral grew/He left the past year's dwelling for the new." He finds in the mysterious life and death of the nautilus strong inspiration for his own life and spiritual growth. He concludes:

Build thee more stately mansions, O my soul,
As the swift seasons roll!
Leave thy low-vaulted past!
Let each new temple, nobler than the last,
Shut thee from heaven with a dome more vast,
Till thou at length art free,
Leaving thine outgrown shell by life's unresting sea!

A painting by Andrew Wyeth, entitled Chambered Nautilus, shows a woman in a canopied bed; the composition and proportions of the bed and the window behind it mirror those of a chambered nautilus lying on a nearby table.

The popular Russian rock band Nautilus Pompilius (Template:Lang-ru) is named after the species.

American composer and commentator Deems Taylor wrote a cantata entitled The Chambered Nautilus in 1916.

  • 16th-century Northern Mannerist nautilus cup
    16th-century Northern Mannerist nautilus cup
  • Nautilus shells engraved to commemorate Horatio Nelson, displayed at Monmouth Museum
    Nautilus shells engraved to commemorate Horatio Nelson, displayed at Monmouth Museum
  • A big nautilus[13]
    A big nautilus[13]
  • Cutaway of a nautilus shell showing the chambers
    Cutaway of a nautilus shell showing the chambers
  • Empty nautilus shell, whole
    Empty nautilus shell, whole
  • Internal anatomy of Nautilus pompilius
    Internal anatomy of Nautilus pompilius

References

  1. ^ a b c Ward, Peter. "Nautilus: Chambers of secrets". New Scientist. Retrieved 2016-12-13.
  2. ^ Basil, Jennifer A.; et al. "Three-dimensional odor tracking by Nautilus pompilius" (PDF). Journal of Experimental Biology. 203 (9).
  3. ^ Ryoji, W.; et al. (2008). "First discovery of fossil Nautilus pompilius (Nautilidae, Cephalopoda) from Pangasinan, northwestern Philippines". Paleontological Research. 12 (1): 89–95. doi:10.2517/1342-8144(2008)12[89:FDOFNP]2.0.CO;2.
  4. ^ Broad, William (24 October 2011). "Loving the Chambered Nautilus to Death". The New York Times. Archived from the original on 27 October 2011. Retrieved 24 October 2011.
  5. ^ "Chambered Nautilus – Conservation & Management". NOAA Fisheries. Retrieved 5 October 2019.
  6. ^ a b c "The Chronicles of Nautilus". Monterey Bay Aquarium. Spring 2018. Retrieved 5 October 2019.
  7. ^ Norman, M. (2000). Cephalopods – A World Guide. ConchBooks. pp. 24–29.
  8. ^ "Mysterious nautilus hatch at Monterey Bay Aquarium". KSBW Action News 8, official YouTube channel. 13 December 2017. Retrieved 5 October 2019.
  9. ^ a b c Ward, Peter (1988). In Search Of Nautilus. New York: Simon and Schuster. pp. 72. ISBN 0-671-61951-9.
  10. ^ Pisor, D.L. (2008). Registry of World Record Size Shells. Fifth edition. ConchBooks, Hackenheim. 207 pp. ISBN 0615194753.
  11. ^ Nautilus pompilius suluensis ID:626793. Shell Encyclopedia, Conchology, Inc.
  12. ^ a b c d e f Ward, Peter (1988). In Search of Nautilus. New York: Simon and Schuster. pp. 160. ISBN 0-671-61951-9.
  13. ^ "Nautilus Cup". The Walters Art Museum.
  • Norman, M. 2000. Cephalopods: A World Guide. Hackenheim, ConchBooks, pp. 30–31.
  • Pisor, D. L. (2005). Registry of World Record Size Shells (4th ed.). Snail's Pace Productions and ConchBooks. p. 93.
  • Ward, Peter (1988) In Search Of Nautilus: Three Centuries of Scientific Adventures in the Deep Pacific to Capture a Prehistoric, Living Fossil. New York: Simon and Schuster, Print.
  • Ward, Peter (2008) Chamber of Secrets. New Scientist, April 02 2008
Wikimedia Commons has media related to Nautilus pompilius.
Wikisource has the text of the 1921 Collier's Encyclopedia article Pearly nautilus.
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