These chamber-shelled cephalopods first appeared around 550 million years ago. The peak of its ancestors' dominance was during the early Paleozoic era where some had shells with a length of twenty or thirty feet if uncoiled. Despite this rich fossil record, only six closely related species of this genus are known to still exist. They are now referred to as living fossils because of their evolutionary history.
(Attenborough 1979, Abbot 1935, Dybas 1994)
Researchers study N. pompilius for many reasons. First, there is a process called biominetrics that strives to synthetically produce such organic materials as nacre, or the mother of pearl that lines the inside of N. pompilius' shell. This thin coating is incredibly strong, and this synthesized material would be used in small machines. Researchers are mainly interested in understanding how these materials are made naturally. In addition, N. pompilius has the most highly developed pinhole eyes, making them the subject of much research. This relatively uncommon eye type lacks lenses.
(Clery 1992, Nilsson 1989)
Due to its primitive eyes and sensitivity to light, N. pompilius relies on its sense of smell to detect the fishes and crabs that it feeds on. They also feed on carrion.
(Attenborough 1979, Morton 1979)
Nautilus pompilius is found in the Indo-Pacific area. They primarily live near the bottom, in waters up to 500 meters deep, but rise closer to the surface throughout the night.
(Morton 1979)
Biogeographic Regions: pacific ocean (Native )
They live along the bottom of the shores and coral reefs of the South Pacific.
(Abbot 1935)
Aquatic Biomes: reef ; coastal
Nautilus pompilius can grow to a length of about 20 cm. The smooth thin shell spirals exogastrically, or above the animal, and has a pattern of brown and white. The animal creates chambers that increase in size as it moves to occupy the outermost chamber of its shell. An adult may have about 30 of these chambers. A tube called a siphuncle runs down the center of these chambers releasing a gas to maintain buoyancy and to keep N. Pompilius in an upright position. There is a tough hood where the anterior of its body connects to the shell. Below the hood protrudes about 90 small suckerless tentacles. Beneath, there is a funnel containing two separate lobes. The eyes contain no cornea or lens.
(Attenborough 1979, Morton 1979, Brusca and Brusca 1990)
Other Physical Features: ectothermic ; bilateral symmetry
This species reproduces sexually through internal fertilization and reaches sexual maturity at age 15 to 20 years. Four of the tentacles on the male form the spandix, which transfers sperm by means of a spermatophore. A spermatophore contains an elongated sperm mass that adheres to the female's mantle wall. The protective coating disintegrates, releasing the sperm. They then lay oblong eggs that are around 1.5 inches in length. The newly hatched chambered nautilus has a small shell that is about one inch in diameter.
(Brusca and Brusca 1990, Dybas 1994)
The chambered nautilus (Nautilus pompilius), of the family Nautilidae, is native to the Indo-Pacific region of the ocean. It is present in waters that span from the Andaman Islands and the Philippines in the north, with Fiji and Australia at the southern end of the range (Reyes 2016). N. pompilius lives deep in the ocean above coral reefs and is sometimes found as deep as 750 m (2,460 feet). However, it cannot travel lower than 800 m (2,625 feet), as this could cause the shell to implode. The species also cannot survive temperatures above 25˚C (77˚F) (Jereb and Roper 2005).
Adult N. pompilius exhibits slight size differences between the sexes. Male average diameter is 131.9 mm and females average 118.9 mm (Dunstan, Ward and Marshall 2011). It is difficult to get an accurate weight for the species because there are differing amounts of seawater within its shell at a given time. Studies of N. pompilius in the Philippines reported an average weight of 850 g (30 ounces) for a large specimen (diameter of 165 mm) (Saunders and Landman 2009). The body of N. pompilius is contained within a spiral shaped shell that is a pearly white color with deep crimson stripes. This external shell is unique to the nautilus and has not changed much from its ancestors 500 million years ago. Within the fully matured shell, there are 30 – 38 chambers. The nautilus’ body occupies only the first segment, while the chambers behind are filled with gases and fluid (Cerullo 1997), which allow it to float and travel above the ocean floor (Lemanis, Zachow, Fusseis and Hoffmann 2015). When first hatched, the juvenile nautilus only possesses seven chambers (Saunders and Landman 2009). In this stage, N. pompilius lives near the floor of the sea and is entirely covered in stripes to help them camouflage themselves. Adult N. pompilius’ stripes become concentrated only on the tops of their shells to better camouflage them in their new habitat in the water column.
N. pompilius remains generally unobserved in its natural deep sea habitat, therefore, most of the information about behavior and life history comes from aquariums that breed them (Dunstan, Ward and Marshall 2011). N. pompilius is mainly a solitary animal (Basil et al. 2002) that remains at the bottom of the sea during the day and travels vertically into more shallow depths at night to find prey. A carnivore, the N. pompilius feeds on molted shells, the carcasses of dead animals, as well as fish, crabs and other crustaceans. N. pompilius catches food in its adhesive tentacles and transfers it to its mouth. Here, the strong jaws crack through the shells of prey (Saunders and Landman 2009).
When threatened, the nautilus can retract completely into its shell and hide behind its leather-like hood (Jereb and Roper 2005). To travel, this species controls the concentration of gases and sea water within its chambers to achieve buoyancy (Lemanis, Zachow, Fusseis and Hoffmann 2015). The nautilus also utilizes jet propulsion by forcing water out of the funnel beneath its tentacles, in order to move up and down in the water column. The siphuncle is a separate structure within the chambers that allows fluid to flow in or out, to maintain buoyancy at different water depths (Saunders and Landman 2009). The chambered nautilus has very poor eyesight and finds its food using its tentacles’ ability to detect scent (Crook and Basil 2008). Although it lacks the degree of brain development of octopi, squids and cuttlefish, the nautilus does have the ability to learn simple associations, such as the connection between a pulsing light and feeding time. Through laboratory studies, this animal has been proven to employ both short- and long-term memory (Crook and Basil 2008).
During the mating process, the male nautilus uses his spadix, a structure made up of four combined tentacles, to deliver sperm to the female (Jereb and Roper 2005). The female lays 10 fertilized eggs annually, which measure up to 45 mm (Eldredge and Stanley 2012). Females are seen sticking the eggs to hard surfaces with their tentacles (Jereb and Roper 2005). It takes 10-12 months for the eggs to hatch (Dunstan, Bradshaw and Marshall 2011). When newly emerged, N. pompilius measures approximately 23 mm in diameter (Saunders and Landman 2009). Juveniles in captivity are observed to consume small shrimp soon after hatching (Jereb and Roper 2005). The nautilus has a slow rate of development. The species reaches maturity roughly 15 years after hatching and has a life expectancy of more than 21 years. (Dunstan, Ward and Marshall 2011).
Although N. pompilius is preyed upon by sharks, fish and octopi, human harvesting is the main danger to its population size (U.S. Fish and Wildlife Service 2016). Populations are considered vulnerable to extinction due to loss of natural habitat, low reproduction rate and over-harvesting (De Angelis 2012).The beauty of its shell has caused the chambered nautilus to be a target for profit. Some isolated populations of the nautilus have seen 100% reduction after just two years of over-fishing.Even in locations untouched by harvesting, it is estimated that only fifteen nautiluses are present per square kilometer of habitat (.386 square miles) (U.S. Fish and Wildlife Service and National Oceanic and Atmospheric Administration Fisheries 2016). N. pompilius was previously not a protected species due to a lack of knowledge regarding the international population size (De Angelis 2012). During the 2016 Convention on International Trade in Endangered Species of Wild Fauna and Flora, it was finally agreed that the entire Nautilidae family would become listed as species requiring international controls on harvesting (Convention on International Trade in Endangered Species 2016).
The chambered nautilus (Nautilus pompilius), of the family Nautilidae, is native to the Indo-Pacific region of the ocean (Reyes 2016). N. pompilius lives in the sea above coral reefs and is sometimes found in habitats as deep as 750m (2,460 feet) (Jereb and Roper 2005). Adult male nautiluses reach an average diameter of 131.9 mm (5 3/16 inches), while females reach an average of 118.9 mm (4 11/16 inches) (Dunstan, Ward and Marshall 2011). The body of N. pompilius is contained within a spiral shaped shell that is a pearly white color with deep crimson stripes on the top and solid white underneath. Juveniles are striped over their entire shells. Chambers contained within the center of the shell are filled with gases and seawater which allow the species to be buoyant (Lemanis, Zachow, Fusseis and Hoffmann 2015). The nautilus can also swim and travel via jet propulsion. Generally, these animals travel to shallower depths at night to feed on crustaceans and carrion, which they locate using their odor-sensing tentacles (Saunders and Landman 2009) (Crook and Basil 2008¬). N. pompilius employs both short- and long-term memory and is able to learn simple associations (Crook and Basil 2008¬). The chambered nautilus utilizes internal fertilization and lays approximately ten eggs each year (Eldredge and Stanley 2012). These eggs take 1 year to hatch, while the animal takes 15 years to mature and lives over 21 years (Dunstan, Bradshaw and Marshall 2011) (Dunstan, Ward and Marshall 2011). Because of its low reproductive rate and slow life history, N. pompilius is in danger of extinction due to over-fishing to supply the demand for nautilus shells (De Angelis 2012). After the elimination of several local nautilus populations, it was agreed in 2016 that international controls would be enforced over trade of this species. (De Angelis 2012) (Convention on International Trade in Endangered Species 2016).
Its relatives the ammonoids dominated the oceans for millions of years before going extinct along with the dinosaurs 65 million years ago – but the nautilus came through that disaster and is still with us today...
read more“3.1. Nautilus pompilius Linnaeus, 1758
3.1.1. Diagnosis
Mature shell size variable, but typically about 165 mm (Philippines), with a total weight (body plus shell) of about 850 g. Shell has a small umbilicus (≈ 5% of shell diameter), filled with a callus (with rare exceptions); shell coloration variable, but generally comprises irregularly radiating brown stripes that extend from umbilicus to venter.
3.1.2. Discussion
The type species of the genus (and the most common and widely distributed), N. pompilius appears to exhibit the greatest range in variation (Fig. 4). The diameters of 234 mature specimens caught during the 1979 ALPHA HELIX Expedition to the Tañon Straits, the Philippines, ranged from 150 mm (mature female) to 188 mm (barely mature male), with a mean of 165 mm. Sexual dimorphism is shown by slightly smaller females (mean diameter 160 mm) compared to males (mean 170 mm). Specimens of this species (provided by D. Dan) purported to have been caught live, off Tubbataha Reef, central Sulu Sea, the Philippines (Fig. 3C and D), are the smallest known representatives of this species, ranging from 103 to 126 mm in mature shell diameter, with a mean of 114 mm (N = 29). In Papua New Guinea, the average mature size of geographically isolated populations of N. pompilius varies considerably, from 144 mm (Lae, on the north coast of Papua New Guinea) to 169 mm (Kavieng, New Ireland Province), with an overall range in individual (mature) size of 124-199 mm in diameter (Saunders and Davis, 1985). Specimens of this species from Queensland average 153 mm in diameter (N = 5). The cause for the wide range in variation in mature size is not known; it may be genetic, or it may be related to ecological factors.
Variation in the pattern of shell coloration is manifest as differences in the amount of coloration, hue, degree of coalescence of banding over the venter, and development of color bands in the vicinity of the umbilicus. There appears to be a trend toward an increased proportion of shells with a white umbilical region, going southward through Papua New Guinea toward Australia (compare Fig. 2B, C, D).
The number of specimens with an open umbilicus (i.e., lacking an umbilical callus) does not appear to vary systematically; typically, fewer than 0.025% of live-caught N. pompilius in the Philippines and in Papua New Guinea show this curious abnormality (see also Mapes et al., 1979). In N. pompilius, the umbilical callus is secreted during the growth of the second whorl, at approximately 75- mm diameter in Philippine specimens.
3.1.3. Distribution
In his description of N. pompilius, Linnaeus stated only that it "inhabits the Indian and African Ocean" (Turton, 1806, p. 305). However, because his reference to an illustration was that of Rumphius (1741, Plate 17, Figs. A–C), Amboina (Ambon), Indonesia (the source of the specimens illustrated by Rumphius), is the type locality for the species. Nevertheless, this species is best known from the Philippines, and it has been the subject of a number of studies (e.g., Griffin, 1900; Dean, 1901; Bidder, 1962; Haven 1972, 1977a,b; Hayasaka et al., 1982; Hayasaka, 1983: Cochran et al., 1981; Ward and Chamberlain, 1983; Arnold, 1985), particularly in the Tañon Straits, between Cebu and Negros, which was the site of research expeditions, based on the R/V ALPHA HELIX, in 1975 and 1979.*
Occurrences of N. pompilius in Fiji have been reported by Moseley (1892), Davis and Mohorter (1973), Ward et al. (1977), Ward and Martin (1980), Masuda and Shinomiya (1983), Zann (1984), and Hayasaka (1985). A single live animal is captured off Kagoshima Bay, south Japan (Tanabe and Hamada, 1978; JE-COLN, 1980b). Other reports substantiate the existence of living populations in the Andaman Islands (Smith, 1887) and the New Hebrides (Owen, 1832; Bennett, 1834), and this species is widely distributed in the Papua New Guinea region, including New Britain, New Ireland, Manus, Lae, and Port Moresby (Willey, 1895, 1896, 1897a,c, 1898a, 1899, 1902; Saunders and Davis, 1985; Saunders et al., 1987a). The existence of living N. pompilius from the Great Barrier Reef, Australia, has been established just recently with the capture of six specimens off Lizard Island, Queensland, at depths of 200-400 m (Saunders and Ward, 1987), and in 1986, 39 specimens were trapped outside Pago Pago Harbor, American Samoa (Saunders et al., 1987b). The even wider distribution of drifted shells of N. pompilius (see Chapter 4) makes it certain that many more occurrences remain to be discovered.
* For results of these expeditions, see the Journal of Experimental Biology, Vol. 205 (1978), and Pacific Science, Vol. 36 (1982).”
(Saunders, 1987: 39-41)
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.[2]
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.[3]
The oldest fossils of the species are known from Early Pleistocene sediments deposited off the coast of Luzon in the Philippines.[4]
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.[2] Indeed, the taxon of the chambered nautilus, Nautilus pompilius is actually a grouping of tens of different species of nautilus under one name.[2]
All nautilus species are threatened due to overfishing for their shell, which primarily is used for jewelry and other ornamental artifacts.[5] 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.[6]
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.[7] 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.[8] 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.[7] 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.[9] Like other nautilus but unlike most other cephalopods, chambered nautilus are relatively long-lived and only reach maturity when about 5 years old.[7]
As a carnivore, it feeds on both underwater carrion and detritus, as well as living shellfish and crab.[10] Mainly scavengers, chambered nautiluses have been described as eating "anything that smells".[10] 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.
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)[11] 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.[12]
.jpg)
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.
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.[13] This was found during research done in New Caledonia on nautiluses whose shell chamber fluid densities were tested at various depths, weeks apart.[13] Generally speaking, chambered nautiluses inhabit a depth around 1000 feet, although further tests demonstrated that they can, and do, dive deeper.[13] 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.[13]
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.[13] All of the smaller chambers, once uninhabited, are used in the method described above to regulate depth.[13]
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 (Russian: Наутилус Помпилиус) 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
Nautilus shells engraved to commemorate Horatio Nelson, displayed at Monmouth Museum
.jpg)
A big nautilus
Cutaway of a nautilus shell showing the chambers
Empty nautilus shell, whole
Internal anatomy of Nautilus pompilius
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.
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.
The oldest fossils of the species are known from Early Pleistocene sediments deposited off the coast of Luzon in the Philippines.
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. Indeed, the taxon of the chambered nautilus, Nautilus pompilius is actually a grouping of tens of different species of nautilus under one name.
All nautilus species are threatened due to overfishing for their shell, which primarily is used for jewelry and other ornamental artifacts. 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.
