the whiskered auklet ( aethia pygmaea ) is a small seabird of the auk family .

it has a more restricted range than other members of its genus , aethia , living only around the aleutian islands and on some islands off siberia ( like commander islands ) , and breeding on these islands .

it is one of the smallest alcids , only the closely related least auklet being smaller .

its name is derived from the long white feathers on its face that are part of its breeding plumage .

the whiskered auklet is a poorly studied species and much research needs to be undertaken on the species .

it was originally described as two different species , from specimens collected at different ends of its range , however research has shown that it is a single species with clinal variation along its range .

it is not thought to undertake migration , but instead attends its breeding islands year round .

whiskered auklets lay a single egg in a rocky crevice , in loose colonies with other whiskered auklets and also other colonial seabirds .

both parents take part in incubation and chick rearing .

the whiskers have been shown to help them sense their way to and out of their nests at night .

whiskered auklets feed in the inshore zone , usually within 16 km of land , where tidal currents concentrate their prey into dense swarms .

they feed predominantly on copepods during the summer months , mostly on the species neocalanus plumchrus ; and switching to euphausiid krill in the fall and winter .

whiskered auklet

whiskered auklet <EOT> we had a whiskered auklet bounce into our boat and get stunned . that gave us a great opportunity to study it up close . little tanaga strait in the aleutian islands , alaska . 1 june 2016

poorly known to most birders , the whiskered auklet is a small seabird confined to remote areas of the aleutian islands , alaska ( as well as the commander and kurile islands off eastern asia ) . relatively scarce and secretive , it is active around its nesting colonies mostly at night . unlike most auks , it seldom ventures more than a few miles away from shore . one odd distinction shared with its relative , crested auklet : the plumage has a noticeable odor like citrus .

nettleship , d . n . & kirwan , g . m . ( 2018 ) . whiskered auklet ( aethia pygmaea ) . in : del hoyo , j . , elliott , a . , sargatal , j . , christie , d . a . & de juana , e . ( eds . ) . handbook of the birds of the world alive . lynx edicions , barcelona . ( retrieved from urltoken on 9 july 2018 ) .

whiskered auklets flock together while feeding and both parents carry plankton back in their throat pouches to their young . nests are located in rocky crevices on ledges that are very difficult for predators such as gulls , falcons , foxes , and rats to reach .

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del hoyo , j . , collar , n . j . , christie , d . a . , elliott , a . and fishpool , l . d . c . 2014 . hbw and birdlife international illustrated checklist of the birds of the world . volume 1 : non - passerines . lynx edicions birdlife international , barcelona , spain and cambridge , uk .

justification : this species has a very large range , and hence does not approach the thresholds for vulnerable under the range size criterion ( extent of occurrence < 20 , 000 km2 combined with a declining or fluctuating range size , habitat extent / quality , or population size and a small number of locations or severe fragmentation ) . despite the fact that the population trend appears to be decreasing , the decline is not believed to be sufficiently rapid to approach the thresholds for vulnerable under the population trend criterion ( > 30 % decline over ten years or three generations ) . the population size is very large , and hence does not approach the thresholds for vulnerable under the population size criterion ( < 10 , 000 mature individuals with a continuing decline estimated to be > 10 % in ten years or three generations , or with a specified population structure ) . for these reasons the species is evaluated as least concern .

the global population is estimated to number > c . 100 , 000 individuals ( del hoyo

. 1996 ) , while the population in russia has been estimated at < c . 100 breeding pairs and < c . 50 individuals on migration ( brazil 2009 ) .

the population is suspected to be in decline owing to predation by invasive species and ongoing habitat destruction .

this species is found offshore and along sea coasts in summer and is mostly pelagic in winter . its diet includes a high variety of planktonic crustaceans , and infrequently small fish and squid . it forages mainly offshore in deep water , and sometimes in near - shore regions almost always in large flocks throughout the year . birds arrive at colonies from march to june depending on the site . it is highly monogamous with high site and mate fidelity throughout its breeding life . colonies can be as large as 100 , 000 pairs and form on remote islands and coasts in a variety of different rocky habitats . densities are determined largely by the availability of suitable rock crevices and cavities for nesting ( del hoyo et al . 1996 ) .

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total population probably very low compared to most auks . attracted to lights at night , may be killed by crashing into lighted fishing boats . accidental introduction of rats to nesting islands may be biggest threat .

ocean , tide - rips , rocky coasts . usually at sea within a few miles of islands , in relatively shallow water . favors rough water where currents converge , or where tidal currents race across shallows or through narrow passes between islands . nests on islands among rocks or cliffs .

forages while swimming underwater . depth of dives unknown , but usually feeds in fairly shallow water .

one . dull white . incubation is by both sexes , roughly 35 - 36 days . young : both parents feed young , visiting nests at night , bringing food back in throat pouch . age of young bird at departure from nest not well known , may be about 40 days . fledgling departs by flying away from nest site at night .

small crustaceans . diet not well known , primarily small crustaceans including copepods , euphausiid shrimp , amphipods ; also marine worms , mollusks . may concentrate on copepods in summer , euphausiids in winter .

breeds in colonies , not as densely packed as in related small auks . active at colonies mostly at night , especially when not nesting in association with other species . courtship behavior not well known , includes pairs calling in duet . nest sites in small openings in talus slopes , boulder piles , or crevices in cliffs , sometimes in areas of soil mixed with rock . no nest built , egg laid on bare rock or soil .

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this is a large and highly varied group of birds that do not have many outward similarities . most are water birds that feed on invertebrates or small aquatic creatures . the order is well represented in washington , with seven families :

alcids are diving seabirds of the northern hemisphere . most are more comfortable in and under the water than in the air . while some members of the family fly long distances in post - breeding dispersal or migration , others fly only with effort . underwater , they use their wings as flippers to swim after fish , krill , and other aquatic prey . the majority nest in colonies on islands , and many are active in these colonies only at night , spending the day foraging on open water far from their nesting sites . many nest in burrows , and most species lay only one egg each year , although some lay two . both sexes incubate and care for the young . most alcids are predominantly black - and - white , with different breeding and non - breeding plumages .

one record , from penn cove ( whidbey island , island county ) in may 1999 .

analysis of mtdna suggests that present species and a . cristatella form a clade , with a . psittacula a close relative of the two . birds from kuril is were separated as race camtschatica on basis of different body size , but recent studies confirm existence only of simple clinal variation , size increasing from e to w . monotypic .

ne sea of okhotsk ( penzhin gulf , yamskiye is , iony i ) and commander is s to at least c kuril is , and throughout aleutians e to four mountains is and krenitzen is . winters mostly near breeding locations , but s as far as japan , and casual in n bering sea ( e . g . st lawrence i ) .

17–18 cm ; c . 116 g ( 99–136 g ) ; wingspan c . 37 cm . unique head pattern , with long recurved crest on forehead drooping forward over small white - tipped scarlet bill . . .

offshore and along sea coasts . breeds on bare to partially covered talus slopes and beach boulder . . .

diet throughout year marine zooplankton , with 42 different prey taxa identified during a breeding - season study at three islands in the . . .

breeding phenology poorly known . spring arrival apr to early may ; laying probably late may and early jun , sometimes advanced ; hatching and . . .

distribution and movements outside breeding season poorly known . returns to colonies apr to early . . .

not globally threatened ( least concern ) . total population small , second - rarest alcid in alaska . numbers poorly known , but coarse estimates in 1990s indicated minimum of 100 , . . .

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this map displays aggregated data from ibc and my birding ( anonymously ) ; markers do not indicate precise localities .

hbw alive contains information on descriptive notes , voice , habitat , food and feeding , breeding , movements , status and conservation plus a list of bibliographical references for this species account .

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a big group of birds calling while swimming at the sea and then flying .

hal and kirsten snyder , jacob . wijpkema , christophe gouraud , r . d . wallace , niels poul dreyer , kirk zufelt , william price .

recommended citation birdlife international ( 2018 ) species factsheet : aethia pygmaea . downloaded from urltoken on 09 / 07 / 2018 . recommended citation for factsheets for more than one species : birdlife international ( 2018 ) iucn red list for birds . downloaded from urltoken on 09 / 07 / 2018 .

cincinnati zoo & botanical garden 3400 vine st . cincinnati , ohio 45220 ( 513 ) 281 - 4700


scydosella is a genus of beetles that consists of only one species scydosella musawasensis .

the species is regarded as the smallest free-living insect , as well as the smallest beetle .

they are among featherwing beetle , named because of their feather-like spiny wings .

it was first discovered in nicaragua , and described in 1999 by wesley eugene hall of the university of nebraska state museum .

the initial discovery consisted of very few specimens , and exact measurements were not conclusive .

because of their tiny size , they were difficult to observe under microscope after preservation .

the generally accepted size was 0.300 mm in length .

on 8 february 2015 , alexey polilov of the lomonosov moscow state university collected 85 specimens in chicaque national park , colombia .

they were discovered on a layer of fungus on which they feed .

from these specimens exact measurements could be made , and was found that the smallest individual is only 0.325 mm long .

the largest individual is 0.352 mm long , and the average length of all the specimens is 0.338 mm .

the body is elongated and oval in shape , yellowish-brown in colour , and its antennae are split into 10 segments .

scydosella

scydosella <EOT> this tiny insect , scientifically known as scydosella musawasensis , is the only species in the featherwing beetle genus scydosella .

according to a new study published online this week in the journal zookeys , the smallest examined representative of scydosella musawasensis has a length of 0 . 325 mm .

habitus and diagnostic characters of scydosella musawasensis , sem : a dorsal view b lateral view c ventral view d antenna c mouthparts f pygidial tooth g mesosternal process .

“the record of scydosella musawasensis in colombia considerably broadens the known range of this genus and species , known previously only from one site in nicaragua , ” dr polilov wrote .

“this record also broadens the known range of fungi colonized by scydosella musawasensis , which was known previously only from rigidoporus lineatus . i have collected it on steccherinum sp . ”

the smallest known beetle scydosella musawasensis hall is recorded for the second time . precise measurements of its body size are given , and it is shown that the smallest examined representative of this species has a length of 325 µm .

this trend towards fusion into fewer , separate parts affects many organ systems . microinsects like scydosella lack the crops and gizzards present in larger insects , and may also lose the muscles that typically line the esophagus and intestines . the circulatory system in microinsects is basically reduced to nothing more than a simple heart and a short aorta , with scydosella losing those organs entirely . those microinsects with wings suffer from weakly developed veins , which poses a huge problem for flight performance .

the world ' s smallest beetle and tiniest non - parasitoid insect , called scydosella musawasensis , is morphologically characterised by its elongated oval body , yellowish - brown colouration and antennae split into 10 segments . it is also the only representative of this featherwing beetle genus .

the record of scydosella musawasensis in colombia considerably broadens the known range of this genus and species , known previously only from one site in nicaragua ( hall 1999 ) , where the type series was collected : musawas , waspuc river , nicaragua , 14 october 1955 . this record also broadens the known range of fungi colonized by scydosella musawasensis , which was known previously only from rigidoporus lineatus ( meripilaceae , given as polyporus zonalis in the original description ) ( hall 1999 ) ; i have collected it on steccherinum sp . ( meruliaceae ) .

polilov aa ( 2015 ) how small is the smallest ? new record and remeasuring of scydosella musawasensis hall , 1999 ( coleoptera , ptiliidae ) , the smallest known free - living insect . zookeys 526 : 61–64 . doi : 10 . 3897 / zookeys . 526 . 6531

more information : alexey polilov . how small is the smallest ? new record and remeasuring of scydosella musawasensis hall , 1999 ( coleoptera , ptiliidae ) , the smallest known free - living insect , zookeys ( 2015 ) . doi : 10 . 3897 / zookeys . 526 . 6531

polilov aa . 2015 . how small is the smallest ? new record and remeasuring of scydosella musawasensis hall , 1999 ( coleoptera , ptiliidae ) , the smallest known free - living insect . zookeys 526 : 61 - 64 ; doi : 10 . 3897 / zookeys . 526 . 6531

“measuring of ten specimens of scydosella musawasensis has shown that the smallest of them has a length of 0 . 325 mm , the largest has a length of 0 . 352 mm , and the average length is 0 . 338 mm . the body width is 0 . 098 to 0 . 104 mm , ” dr polilov wrote in the zookeys paper .

now that we’ve covered why insects have to be small , the next reasonable question is what keeps them from shrinking even smaller than scydosella ? the problem is that multicellular organisms must make a lot of sacrifices to fit all those structures and organs into such a tiny body . miniaturization in metazoans is actually polilov’s main research interest , and he discussed the unique effects of shrinking on structure and physiology in a paper published earlier this year .

entomologists have declared scydosella musawasensis to be the world’s smallest free - living insect . s . musawasensis , a featherwing beetle , can be as small as 0 . 325 millimeters ( as tiny as certain unicellular organisms ) . alexey polilov of lomonosov moscow state university collected 85 of the beetles from colombia , and his measurements of the tiny specimens confirm their ranking as the world’s tiniest free - living insects . in order to even measure such a tiny organism , polilov had to use a scanning electron microscope with specialized software .

adults of scydosella musawasensis hall , 1999 were collected in chicaque national park , colombia , 10 km west of bogotá , on 8 february 2015 ( coordinates 4 . 619 , - 74 . 312 ) , 2200 m above sea level , on the fungus steccherinum sp . ( meruliaceae ) , 85 specimens . the material was fixed in faa ( formaldehyde—alcohol—acetic acid ) and preserved in 70 % ethanol . it was subsequently examined under a jeol jsm - 6380 scanning electron microscope ( sem ) after drying of the specimens at the critical point ( hitachi hcp - 2 ) and sputter coating with gold ( giko jsm - 6380 ) . the measurements were made using the program meazure ( c thing software ) from digital micrographs obtained under sem .

the smallest known beetle – and the smallest non - parasitoid insect – has a body length of 0 . 325 mm , according to entomologist dr alexey polilov of lomonosov university .

it’s morphologically characterised by its elongated oval body , yellowish - brown coloration and antennae split into ten segments .

“not able to precisely measure its size because of the preserved nicaraguan specimens being embedded in preparations for microscopy studies , i used new individuals , collected in chicaque national park , colombia in early 2015 , ” dr polilov explained .

the measurements were made using specialized software from digital micrographs obtained under a scanning electron microscope .

“thus , the smallest beetle and smallest known non - parasitoid insect has a body length of 0 . 325 mm . ”

the size of the smallest known parasitoid insect , male dicopomorpha echmepterygis ( a parasitic wasp in the family mymaridae ) , is 0 . 139 mm .

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the long - lasting search and debate around the size and identity of the world ' s smallest free - living insect seems to have now been ended with the precise measurement and second record of the featherwing beetle species .

described back in 1999 based on only several specimens found in nicaragua , as many as 85 individuals of the minute beetle species have recently been retrieved from colombia and thoroughly examined . the smallest of them measured the astounding 0 . 325 mm . the finding made by dr . alexey polilov , lomonosov moscow state university moscow , is available in the open access journal zookeys .

not able to precisely measure its size because of the preserved specimens being embedded in preparations for microscopy studies , dr . polilov used new individuals , collected in chicaque national park , colombia in early 2015 . to conclude the length of the smallest one as 325 µm ( 0 . 325 mm ) the scientist used a specialised software and digital micrographs .

, which also proved that the range of its distribution is actually much wider . thereafter , so are the localities of the fungi that the insect feeds on .

a team of japanese scientists found and described a new species of scarab beetle from cambodia . the beetle was named termitotrox venus , after venus - the roman goddess of beauty and love . the study was published in the open - access . . .

minuscule snails defy current knowledge and scientific terminology about terrestrial " microsnails " . while examining soil samples collected from the base of limestone rocks in guangxi province , southern china , scientists barna . . .

recent research from a team led by dr jonathan cox shows how certain beetles use their antennae to locate potential mates . this is the first time scientists have studied molecule capture by the antennae of beetles .

in 1832 charles darwin disembarked from hms beagle in bahia blanca , argentina where he travelled by land to buenos aires . in bahia blanca , darwin collected several fossils of large mammals along with many other living organisms , . . .

a newly - discovered species of tree - killing bark beetle , dendroctonus mesoamericanus armendáriz - toledano and sullivan , has been described in a paper published online in the annals of the entomological society of america by . . .

dr david livingstone ' s only known beetle specimens have been discovered at the museum - 150 years after he brought them back from africa .

the co - evolution of plant—pathogen interactions has been revealed in unprecedented detail in a study of one of the world ' s deadliest crop killers . this is the rice blast pathogen , which destroys enough food to feed more . . .

using genome editing to inactivate a protein called pcsk9 effectively reduces cholesterol levels in rhesus macaques , a species of monkey , according to researchers from the perelman school of medicine at the university of . . .

fish that ' farm ' their own patches of seaweed alter their ' cropping ' practices under high co2 conditions , researchers at the university of adelaide in australia have found .

mucus is able to protect us from infection thanks to ancient genes that have been conserved throughout 350 million years of evolution—dating back to our days as a jellyfish .

by proving a theory that was first proposed almost 40 years ago , researchers have confirmed a new way that cells conserve energy .

our bodies consist of many different kinds of cells , each with their own role . the japanese scientist shinya yamanaka had made earlier the discovery , earning the nobel prize in 2012 , that cells from adult skin can be converted . . .

fairyfly wasps rank smaller than the featherwing beetle me thinks at 0 . 15 mm . check wikipedia entry for fairyfly .

the article specified " free living " , so perhaps that is to rule out the parasitic fairyflies .

yeh ewh that could bee . wonder what free - living means in this case . either way . . . . what a teeny tiny eentsy insect . . . . smaller than a paramecium ; holy cow .

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this is an open access article distributed under the terms of the creative commons attribution license ( cc by 4 . 0 ) , which permits unrestricted use , distribution , and reproduction in any medium , provided the original author and source are credited .

has shown that the smallest of them has a length of 325 µm , the largest has a length of 352 µm , and the average length is 338 µm ( fig .

) . the body width ( maximum width of both elytra at rest ) is 98 to 104 µm ( м = 99 µm , n = 10 ) . thus , the smallest beetle and the smallest known free - living insect has a body length of 325 µm .

) , yellowish - brown , surface generally glabrous , punctation sparse . antennae 10 - segmented ( fig .

) . pronotum widest at middle . procoxal pockets absent , prothoracic glands absent . mesosternal process evenly narrowing anteriad , with obtuse apex , not extending onto metasternum ( fig .

) . mesosternal lines ending near process ; metasternal lines complete . elytral venter with stridulatory file . femoral line ending in 2 setae . pygidial tooth acute ( fig .

this study has been supported by the russian science foundation ( project no . 14 - 14 - 00208 ) .

dybas hs . ( 1990 ) chapter 36 . insecta : coleopteraptiliidae in : dindal dl . ( ed . )

a new genus and species of fairyfly , tinkerbella nana ( hymenoptera , mymaridae ) , with comments on its sister genus kikiki , and discussion on small size limits in arthropods .

a new species of dicopomorpha ( hymenoptera : mymaridae ) with diminutive , apterous males .

morphological and taxonomical novelties in the world’s smallest beetles , and the first old world records of nanosellini .

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why are insects in general so small ? evolution favors small insects for two reasons . the first is their unique respiratory systems ; insects use tubes called trachea that must extend throughout their bodies to deliver oxygen and remove carbon dioxide . the larger the insect , the more space these trachea have to take up to satisfy their increased oxygen demand .

the second constraint on giant insects comes from their chitinous exoskeletons . while this tough outer shell grants insects protection and structure , it also keeps them from growing too large . molting and growing an entirely new coat is an incredibly exhaustive process . as the insect grows larger , it also needs a thicker exoskeleton that would eventually become too heavy to support .

the principle of organs scaling down as the body shrinks is called “allometry . ” microinsects achieve their tiny size through allometry as well as simplifying or entirely eliminating structures . for example , their chitinous exoskeleton constrains their morphology at both ends of the size spectrum . in exchange for smaller size , microinsects give up the thicker protection enjoyed by larger insects . the exoskeleton also becomes less complex and articulate , and the fusion of elements and segments makes the insect less flexible than its larger relatives .

perhaps the most dramatic consequences of miniaturization occur in the nervous system . when forced to fit into such a tiny volume , neurons are reduced in both size and number and must pack together more tightly . the result ? greater noise and interference with the transmission of signals between cells . this also creates an exceptionally dense demand for energy , while leaving less room in each nerve cell for mitochondria , the intracellular structures that provide that energy . microinsects try to get around these handicaps by expanding and contorting their nerves to fit every nook and cranny , but this comes at the expense of other organ systems .

of course , the reproductive system gets top priority . while everything else dwindles , gonads must remain disproportionately large to maintain their function . in particular , females devote a significant portion of their body size to producing a large enough egg for viable offspring . some species of microinsects even produce sperm that are longer than the male’s entire body .

based on these observations , the miniaturization of insects is likely limited by the space required for the most crucial structures in the nervous and reproductive systems . while smaller size certainly gives these insects great advantages in conserving energy and avoiding predators , it also comes with a host of complications . like many things in life , it looks like moderation is key .

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argonauta argo , also known as the greater argonaut , is a species of pelagic octopus belonging to the genus argonauta .

the female of the species , like all argonauts , creates a paper-thin eggcase that coils around the octopus much like the way a nautilus lives in its shell , hence the name paper nautilus .

the chinese name for this species translates as " white sea-horse 's nest " .

a. argo was the first argonaut species to be described and is consequently the type species of the genus .

a. argo is the largest species in the genus and also produces the largest eggcase .

live animals have a characteristic blue sheen on the first arm pair and around the eyes .

the eggcase is characterised by two rows of small , sharp tubercles running along a narrow keel , smooth ribs across the walls of the shell , and a thickening along the shell aperture , which forms distinct protrusions or ' horns ' on either side .

argonauta cygnus monterosato , 1889 was described based on a shell which lacked these protrusions , although it is now considered a junior synonym of a. argo .

the greatest recorded size of an a. argo eggcase is 300.0 mm .

a. argo is cosmopolitan , occurring in tropical and subtropical waters worldwide .

a dwarf form exists in the mediterranean sea , which was described as argonauta argo mediterranea monterosato , 1914 , although this taxon is now regarded as invalid .

a. argo is thought to feed primarily on pelagic molluscs .

the species is preyed on by numerous predators .

it has been reported in the stomach contents of alepisaurus ferox from the south-western pacific .

males of this species reach sexual maturity at a mantle length ( ml ) of 8 mm .

females mature at about double the size of argonauta bottgeri and argonauta hians .

they begin to secrete an eggcase at 6.5 – 7 mm ml .

eggs are usually laid when females reach 14 – 15 mm ml , although the size at which this takes place differs across the animal 's range .

a small a. argo residing in an 88 mm long eggcase was estimated to be carrying 48,800 embryos .

females grow to 100 mm ml , while males do not exceed 20 mm ml .

in the open ocean , a. argo has been observed attached to jellyfish .

this behaviour has been known for a long time , although little was understood about the relationship prior to the work of heeger et al. in 1992 .

in " predation on jellyfish by the cephalopod argonauta argo " , heeger et al. describe their observations of a female a. argo found atop a host jellyfish .

the argonaut was seen holding on to the aboral ( exumbrellar ) surface of the jellyfish using its lateral and ventral arms .

the authors found that about half of the animal 's aboral surface was damaged and large pieces of mesoglea were missing , presumably removed by the argonaut .

additionally , two holes , apparently bite marks , were found in the center of this area with channels leading from these holes into the gastral cavity of the jellyfish .

the argonaut presumably used these channels to suck food particles from the gastral cavity .

heeger et al. suggested that " the association provided shelter or camouflage for the argonaut " .

observations of captive a. argo females suggest that the expanded webs of the dorsal arms may aid the animal in feeding .

mark norman mentions that " when food was touched against the spread webs , an arm shot out of the shell in a sweeping action , grabbing the prey " .

it is speculated that argonauts do not actively hunt , but employ this method to catch animals that bump into them in the open ocean .

a. argo is occasionally involved in mass strandings along the south african and southern australian coastlines .

the strandings are seasonal and generally occur between april and august , towards the end of the animals ' spawning season .

a damaged beak of a female a. argo ( ml = 40.0 mm ; caught at 20 ° 56 ′ n 175 ° 33 ′ w ) , measuring 4.30 mm in hood length and 7.80 mm in crest length , is mentioned in a handbook for the identification of cephalopod beaks .

the type specimen of a. argo was collected in the mediterranean sea and is deposited at the linnean society of london .

argonauta argo

argonauta argo <EOT> forma argonauta argo f . agglutinans martens , 1867 accepted as argonauta argo linnaeus , 1758

forma argonauta argo f . aurita martens , 1867 accepted as argonauta argo linnaeus , 1758

forma argonauta argo f . mediterranea monterosato , 1914 accepted as argonauta argo linnaeus , 1758

forma argonauta argo f . obtusangula martens , 1867 accepted as argonauta argo linnaeus , 1758

variety argonauta argo var . americana dall , 1889 accepted as argonauta argo linnaeus , 1758

figure . two views of argonauta argo atop the jellyfish , phyllorhiza punctata . photographs copyright © , thomas heeger , university of san carlos , philippines .

figure . hectocotylus of argonauta argo . top - oral view . middle - aboral view . bottom - side view . drawings from naef , 1921 - 3 .

figure . left - lateral view of an argonauta argo shell , hawaii . photograph by r . young ) . right - a collection of argonauta nodosa shells from a swarm that washed ashore , australia . photograph by mark norman .

to cite this page : virden , t . 1999 . " argonauta argo " ( on - line ) , animal diversity web . accessed july 09 , 2018 at urltoken

heeger , t . , u . piatkowski and h . möller . 1992 . predation on jellyfish by the cephalopod argonauta argo . marine ecology progress series 88 : 293 - 296 .

figure . view of a portion of the radula of a . argo . drawing from naef ( 1921 - 1923 ) .

okutani , t . and t . kawaguchi . 1983 . a mass occurrence of argonauta argo ( cephalopoda : octopoda ) along the coast of shimane prefecture , western japan sea . venus 41 : 281 - 290 .

figure . side - oblique views of an argonauta argo , photographed in a ship - board aquarium . left - arm i web expanded over shell . right - arm i web retracted . photographs by m . vecchione .

( of argonauta argo f . obtusangula martens , 1867 ) finn j . k . ( 2013 ) taxonomy and biology of the argonauts ( cephalopoda : argonautidae ) with particular reference to australian material . molluscan research 33 ( 3 ) : 143 - 222 . [ details ]

( of argonauta argo f . aurita martens , 1867 ) finn j . k . ( 2013 ) taxonomy and biology of the argonauts ( cephalopoda : argonautidae ) with particular reference to australian material . molluscan research 33 ( 3 ) : 143 - 222 . [ details ]

( of argonauta argo f . agglutinans martens , 1867 ) finn j . k . ( 2013 ) taxonomy and biology of the argonauts ( cephalopoda : argonautidae ) with particular reference to australian material . molluscan research 33 ( 3 ) : 143 - 222 . [ details ]

( of argonauta argo var . americana dall , 1889 ) finn j . k . ( 2013 ) taxonomy and biology of the argonauts ( cephalopoda : argonautidae ) with particular reference to australian material . molluscan research 33 ( 3 ) : 143 - 222 . [ details ]

( of argonauta argo f . mediterranea monterosato , 1914 ) finn j . k . ( 2013 ) taxonomy and biology of the argonauts ( cephalopoda : argonautidae ) with particular reference to australian material . molluscan research 33 ( 3 ) : 143 - 222 . [ details ]

( of argonauta ferussaci monterosato , 1914 ) monterosato t . a . ( di ) ( 1914 ( 30 giugno ) ) . sur les argonauta de la méditerranée . journal de conchyliologie 61 ( 4 ) : 385 - 390 , tabs . x - x3 [ details ]

( of argonauta corrugata humphrey , 1797 ) check list of european marine mollusca ( clemam ) . , available online at urltoken [ details ]

( of argonauta haustrum wood , 1811 ) check list of european marine mollusca ( clemam ) . , available online at urltoken [ details ]

( of argonauta papyria conrad , 1854 ) check list of european marine mollusca ( clemam ) . , available online at urltoken [ details ]

( of argonauta monterosatoi coen , 1915 ) coen g . ( 1915 ) . delle forme adriatiche di argonauta ed in particolare dell ' a . monterosatoi n . sp . . annali del museo civico di storia naturale di genova ( 3 ) 6 ( 46 ) : 261 - 275 , pl . 5 [ details ]

figure . lateral view of a juvenile female ( 6 . 5 mm ml ) argonauta hians showing the web on arms i , equatorial south atlantic . drawing from chun , 1910 .

figure . side and ventral views of the funnel and mantle locking - apparatus of argonauta hians , juvenile male , 5 . 0 mm ml , equatorial south atlantic . drawing from chun , 1910 .

figures . lateral and oral views of male argonauts . left , center - a 5 mm ml , apparently immature , male argonauta hians from the equatorial south atlantic . drawings from chun , 1910 . in oral view the male looks like a 7 - arm octopus . right - a male argonauta nodosa , off australia , with the hectocotylus in a much larger sac is apparently mature . photograph by mandy reid ; provided by mark norman .

( of argonauta minor risso , 1854 ) finn j . k . ( 2013 ) taxonomy and biology of the argonauts ( cephalopoda : argonautidae ) with particular reference to australian material . molluscan research 33 ( 3 ) : 143 - 222 . [ details ]

( of argonauta ferussaci monterosato , 1914 ) finn j . k . ( 2013 ) taxonomy and biology of the argonauts ( cephalopoda : argonautidae ) with particular reference to australian material . molluscan research 33 ( 3 ) : 143 - 222 . [ details ]

( of argonauta monterosatoi monterosato , 1914 ) finn j . k . ( 2013 ) taxonomy and biology of the argonauts ( cephalopoda : argonautidae ) with particular reference to australian material . molluscan research 33 ( 3 ) : 143 - 222 . [ details ]

( of argonauta cygnus monterosato , 1889 ) finn j . k . ( 2013 ) taxonomy and biology of the argonauts ( cephalopoda : argonautidae ) with particular reference to australian material . molluscan research 33 ( 3 ) : 143 - 222 . [ details ]

( of argonauta pacificus dall , 1871 ) finn j . k . ( 2013 ) taxonomy and biology of the argonauts ( cephalopoda : argonautidae ) with particular reference to australian material . molluscan research 33 ( 3 ) : 143 - 222 . [ details ]

( of argonauta corrugatus humphrey , 1797 ) finn j . k . ( 2013 ) taxonomy and biology of the argonauts ( cephalopoda : argonautidae ) with particular reference to australian material . molluscan research 33 ( 3 ) : 143 - 222 . [ details ]

( of argonauta papyraceus röding , 1798 ) finn j . k . ( 2013 ) taxonomy and biology of the argonauts ( cephalopoda : argonautidae ) with particular reference to australian material . molluscan research 33 ( 3 ) : 143 - 222 . [ details ]

( of argonauta sulcatus lamarck , 1801 ) finn j . k . ( 2013 ) taxonomy and biology of the argonauts ( cephalopoda : argonautidae ) with particular reference to australian material . molluscan research 33 ( 3 ) : 143 - 222 . [ details ]

( of argonauta grandiformis perry , 1811 ) finn j . k . ( 2013 ) taxonomy and biology of the argonauts ( cephalopoda : argonautidae ) with particular reference to australian material . molluscan research 33 ( 3 ) : 143 - 222 . [ details ]

( of argonauta haustrum dillwyn , 1817 ) finn j . k . ( 2013 ) taxonomy and biology of the argonauts ( cephalopoda : argonautidae ) with particular reference to australian material . molluscan research 33 ( 3 ) : 143 - 222 . [ details ]

( of argonauta monterosatoi coen , 1915 ) finn j . k . ( 2013 ) taxonomy and biology of the argonauts ( cephalopoda : argonautidae ) with particular reference to australian material . molluscan research 33 ( 3 ) : 143 - 222 . [ details ]

( of argonauta dispar conrad , 1854 ) finn j . k . ( 2013 ) taxonomy and biology of the argonauts ( cephalopoda : argonautidae ) with particular reference to australian material . molluscan research 33 ( 3 ) : 143 - 222 . [ details ]

( of argonauta compressus blainville , 1826 ) finn j . k . ( 2013 ) taxonomy and biology of the argonauts ( cephalopoda : argonautidae ) with particular reference to australian material . molluscan research 33 ( 3 ) : 143 - 222 . [ details ]

( of argonauta papyrius conrad , 1854 ) finn j . k . ( 2013 ) taxonomy and biology of the argonauts ( cephalopoda : argonautidae ) with particular reference to australian material . molluscan research 33 ( 3 ) : 143 - 222 . [ details ]

( of argonauta naviformis conrad , 1854 ) finn j . k . ( 2013 ) taxonomy and biology of the argonauts ( cephalopoda : argonautidae ) with particular reference to australian material . molluscan research 33 ( 3 ) : 143 - 222 . [ details ]

( of argonauta bulleri kirk , 1886 ) finn j . k . ( 2013 ) taxonomy and biology of the argonauts ( cephalopoda : argonautidae ) with particular reference to australian material . molluscan research 33 ( 3 ) : 143 - 222 . [ details ]

( of argonauta sebae monterosato , 1914 ) finn j . k . ( 2013 ) taxonomy and biology of the argonauts ( cephalopoda : argonautidae ) with particular reference to australian material . molluscan research 33 ( 3 ) : 143 - 222 . [ details ]

banas , p . t . , d . e . smith and d . c . biggs . 1982 . an association between a pelagic octopod , argonauta sp . linnaeus 1758 , and aggregate salps . fish . bull . u . s . 80 : 648 - 650 .

embryonic development begins in the oviducts . older embryos are attached to the inner region of the shell where they are brooded . the elongate egg stalks ( extensions of the egg chorion ) are woven together and attached to the shell apex on its inner surface . a female a . argo with a shell length of 88 mm was estimated to be carrying 48 , 800 embryos ( okutani and kawaguchi , 1983 ) . the eggs are very small ( 0 . 6 - 1 . 0 mm ) . spawning is intermittent , and the brooding embryos can be seen to be in different stages of development .

figure . side view of argonauta sp . , showing the expansion of the web ( web presence indicated by their chromatophores ) of the first arm , past the horn of the shell and over most of the shell surface , gulf of aqaba , red sea . photograph of living argonaut by shai enbinder ; provided by nadav shashar .

( of argonauta cygnus monterosato , 1889 ) monterosato t . a . ( di ) ( 1889 ( 1 gennaio ) ) . coquilles marines marocaines . journal de conchyliologie 37 ( 1 ) : 20 - 40 ; 37 ( 2 ) : 112 - 121 . , available online at urltoken page ( s ) : 120 [ details ]

( of argonauta cygnus monterosato , 1889 ) gofas , s . ; afonso , j . p . ; brandào , m . ( ed . ) . ( s . a . ) . conchas e moluscos de angola = coquillages et mollusques d ' angola . [ shells and molluscs of angola ] . universidade agostinho / elf aquitaine angola : angola . 140 pp . ( look up in imis ) [ details ]

( of argonauta minor risso , 1854 ) adam , w . ( 1942 ) . notes sur les céphalopodes : 21 . a propos d ' une publication peu connue de a . risso 1854 [ notes on the cephalopods : 21 . on a hardly known publication from a . risso 1854 ] . bull . mus . royal d ' hist . nat . belg . / med . kon . natuurhist . mus . belg . 18 ( 25 ) : 1 - 36 ( look up in imis ) [ details ]

argonauts are pelagic in tropical and subtropical surface waters of all oceans and seas . sometimes they are found in large swarms , but only rarely are they encountered nearshore . in the open ocean they are commonly found attached to jellyfish ( david , 1965 ) . while this unusual association between argonauta spp . and jellyfish has long been known ( kramp , 1956 ; david , 1965 ) it was uninvestigated prior to the work of heeger et al . ( 1992 ) . the latter authors describe argonauta astride the aboral ( = exumbrellar ) surface of a swimming jellyfish that it held with its lateral and ventral arms . upon examination of the jellyfish they found about half of its aboral surface was damaged and large pieces of mesoglea were missing . two holes , apparently bite marks were found in the center of this area and channels led from these holes into the gastral cavity of the jellyfish . they presumed the octopod used these channels to suck particles ( food ) from the gastral cavity . they also suggest that the association provided shelter or camouflage for the argonaut .

the female lives in a thin , calcareous , laterally compressed shell secreted by its dorsal arms . the shell is paper - thin and the animal is commonly called the " paper nautilus . " the latter part of the name comes from similarly - shaped shell of nautilus . the shell of the pearly nautilus , however , is the true cephalopod shell ( i . e . , the homologue of the molluscan shell ) and not a unique evolutionary innovation like the " shell " of argonauta ( naef , 1921 - 23 ) .

( of argonauta cygnus monterosato , 1889 ) finn j . k . ( 2014 ) . family argonautidae . pp . 228 - 237 , in p . jereb , c . f . e . roper , m . d . norman & j . k . finn eds . cephalopods of the world . an annotated and illustrated catalogue of cephalopod species known to date . volume 3 . octopods and vampire squids . fao species catalogue for fishery purposes [ rome , fao ] . 4 ( 3 ) : 353 pp . 11 pls . page ( s ) : 230 [ details ]

( of argonauta pacificus dall , 1871 ) finn j . k . ( 2014 ) . family argonautidae . pp . 228 - 237 , in p . jereb , c . f . e . roper , m . d . norman & j . k . finn eds . cephalopods of the world . an annotated and illustrated catalogue of cephalopod species known to date . volume 3 . octopods and vampire squids . fao species catalogue for fishery purposes [ rome , fao ] . 4 ( 3 ) : 353 pp . 11 pls . page ( s ) : 230 [ details ]

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have been described . a full list is given by mangold , vecchione and young ( 2008 ) . taxonomic work on this genus is required , but

is undoubtedly a good species and is the type species of the genus . we treat

has been assessed as least concern because , although little is known about this species , its wide distribution , oceanic lifestyle and low interest to fisheries suggest that it is not threatened .

this species is found in surface tropical and subtropical waters of the world ' s oceans . in the atlantic , it extends north to cape cod in the west and portugal in the east and south to brazil in the west and southern africa in the east . it also occurs in the mediterranean sea . in the pacific , its northern limits appear to be california in the east and southern hokkaido in the west . it extends southwards to subtropical waters around australia and new zealand . it is found throughout the indo - west pacific ( nesis 1987 , norman 2000 ) .

albania ; algeria ; american samoa ; angola ; anguilla ; antigua and barbuda ; aruba ; australia ; bahamas ; bangladesh ; barbados ; belize ; benin ; bermuda ; bonaire , sint eustatius and saba ; bosnia and herzegovina ; brazil ; british indian ocean territory ; brunei darussalam ; cambodia ; cameroon ; cape verde ; cayman islands ; china ; christmas island ; cocos ( keeling ) islands ; colombia ; comoros ; congo ; congo , the democratic republic of the ; cook islands ; costa rica ; côte d ' ivoire ; croatia ; cuba ; curaçao ; disputed territory ; djibouti ; dominica ; dominican republic ; ecuador ; egypt ; el salvador ; equatorial guinea ; eritrea ; fiji ; french guiana ; french polynesia ; gabon ; gambia ; ghana ; gibraltar ; greece ; grenada ; guadeloupe ; guam ; guatemala ; guinea ; guinea - bissau ; guyana ; haiti ; honduras ; hong kong ; india ; indonesia ; iran , islamic republic of ; iraq ; italy ; jamaica ; japan ; kenya ; kiribati ; korea , democratic people ' s republic of ; korea , republic of ; kuwait ; liberia ; libya ; macao ; madagascar ; malaysia ; maldives ; malta ; marshall islands ; martinique ; mauritius ; mayotte ; mexico ; micronesia , federated states of ; monaco ; montenegro ; montserrat ; morocco ; mozambique ; myanmar ; namibia ; nauru ; new caledonia ; new zealand ; nicaragua ; nigeria ; niue ; norfolk island ; northern mariana islands ; oman ; pakistan ; palau ; panama ; papua new guinea ; peru ; philippines ; pitcairn ; portugal ; puerto rico ; qatar ; réunion ; russian federation ; saint barthélemy ; saint helena , ascension and tristan da cunha ; saint kitts and nevis ; saint lucia ; saint martin ( french part ) ; saint vincent and the grenadines ; samoa ; san marino ; sao tomé and principe ; saudi arabia ; senegal ; seychelles ; sierra leone ; singapore ; sint maarten ( dutch part ) ; solomon islands ; somalia ; south africa ; spain ; sri lanka ; sudan ; suriname ; taiwan , province of china ; tanzania , united republic of ; thailand ; timor - leste ; togo ; tokelau ; tonga ; trinidad and tobago ; tunisia ; turks and caicos islands ; tuvalu ; united arab emirates ; united states ; united states minor outlying islands ; vanuatu ; venezuela , bolivarian republic of ; viet nam ; virgin islands , british ; virgin islands , u . s . ; wallis and futuna ; western sahara ; yemen

female argonauts secrete a shell using glands on their dorsal arms into which they lay their eggs . they produce the shell early in life ( before maturation ) and use it as a home . males are dwarf and have been reported living within salps ( banas et al . 1982 ) . they have a modified third arm which detaches during mating and carries the spermatophores to the females . female argonauts are often found associated with jellyfish , which they use as a source of food and possibly as camouflage ( heeger et al . 1992 ) . eggs are small ( 50 , 000 ) and are brooded in the shell until they hatch ( laptikhovsky and salman 2003 ) . up to five developmental stages can be present in one shell , which is neutrally buoyant due to the female trapping air at the surface ( jereb et al . 2014 ) . the species is assumed to be semelparous and likely has a lifespan of around one year as is common for other cephalopod species . females probably spawn continuously releasing a batch of around 2 , 000 - 4 , 000 eggs per day over a period of a month or more ( laptikhovsky and salman 2003 ) .

the shells are of interest to the shell trade and the flesh is edible . this species is of limited interest to fisheries but is reported occasionally in indian , japanese and taiwanese ( jereb et al . 2014 ) markets , occasionally with landings of several hundred kilograms ( de bruin et al . 1995 ) . jereb et al . ( 2014 ) state that between the 17th of june and 3rd of july 1982 , around 6 , 300 females were caught in the sea of japan .

there is a potential threat from the shell trade , but mostly trade appears to be of shells that wash up on shores so this cannot be considered a current threat .

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yes , it ' s a cephalopod ! this squid and other cephalopods are featured in the cephalopod pages maintained at the national museum of natural history , department of invertebrate zoology ! see the following links for more information on cephalopods .

cephalopods in action . this is a multimedia appendix to published papers , that features video clips of cephalopods filmed from submersibles . included are :

the list of species featured in the videos , arranged as a taxonomic list , only relevant taxa included .

introducing an interactive key to the families of the decapodiformes . try this , it ' s exciting !

expedition journals from the search for the giant squid off new zealand , 1999 .

this page was created by jim felley , mike vecchione , clyde roper , mike sweeney , and tyler christensen . if you have questions or comments , contact mike vecchione .

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katharina m . mangold ( 1922 - 2003 ) , michael vecchione , and richard e . young

the family contains at least four species ( nesis , 1982 / 7 ) .

argonauts are muscular , pelagic octopods . females secrete a thin calcareous " shell " in which they reside . shells may reach a length of 30 cm ( nesis , 1982 ) . the dorsal arms of females are modified with large , flag - like membranes that expand over the shell and are responsible for the secretion of the shell . eyes are very large and webs very small . the mantle - funnel locking apparatus consists of knob - like cartilages ( mantle ) and matching depressions ( funnel ) . males are dwarfs .

females with distal flag - like expansion of the web of the dorsal arms that contain shell - secreting glands .

presence of external " shell " in females secreted by the dorsal arms . the true molluscan shell ( i . e . , stylets in most incirrates ) is absent .

a list of all nominal genera and species in the argonautidae can be found here . the list includes the current status and type species of all genera , and the current status , type repository and type locality of all species and all pertinent references .

an unusual feature of argonauts is the secreted shell that functions as a brood chamber . the " shell " is not homologous with the true molluscan shell as evidenced by its unique site of formation : the dorsal arms of the female rather than the internal shell sac as in other coleoids . naef ( 1921 / 3 ) noted the remarkable resemblance of the argonaut shell to the shells of some of the abundant cretaceous ammonoids and suggested that the argonaut shell evolved in the following way : ancestral argonauts occupied empty ammonoid shells during the late cretaceous . [ occupancy of molluscan shells by octopodids is common in the present day . ] the octopod evolved glandular structures on the arms to repair the shell of the ammonoids after the latter had become extinct at the end of the cretaceous . eventually , the ammonoid shell was completely replaced by a secreted structure whose shape had been evolutionarily molded by the ammonoid shell . however , as pointed out by young et al . ( 1998 ) , a gap of about 40 million years exists between extinction of ammonoids and the earliest fossil record of an argonaut , and they suggest that the mold for the shell was from some other type of mollusc and that the resemblance to ammonoids is coincidental . the origin of the argonaut shell is a challenging problem and has important implications for understanding the relationships amoung groups of the argonautoidea ( young , et al . , 1998 ) .

the male argonaut is a dwarf , about 10 % of the length of the female . the entire third right arm is hectocotylized and carried in a special sac . at mating , the hectocotylus , which carries one large spermatophore , breaks out of its sac and then from the male body . the free hectocotylus invades , or is deposited in , the female ' s mantle cavity , where it remains viable and active for some time . the hectocotylus was first described as a worm parasitic on the female ( delle chiaje , 1825 ) .

the argonaut paralarva has a distinctive appearance as seen in the photo . the arms are very short and equal in length and are surrounded in their proximal half by a membranous collar or cuff ( barely recognizable in the photograph ) formed by the interbrachial membrane . the latter feature is found also in tremoctopus hatchlings . the life - span is unknown .

- ventrolateral view captured in a plankton tow , hawaii . photograph by r . young .

- side view . drawing from naef ( 1921 - 230 . note the lock and pit of the funnel / mantle locking - apparatus at the bottom of the photograph and drawing .

males have been reported living within salps ( banas et al . , 1982 ) .

chun , c . 1910 . die cephalopoden . oegopsida . wissenschaftliche ergebnisse der deutschen tiefsee expedition auf dem dampfer " valdivia " 1898 - 1899 , 18 ( 1 ) : 1 - 401 .

david , p . m . 1965 . the surface fauna of the ocean . endeavour ( oxf . ) 24 : 95 - 100 ) .

delle chiaje , s . 1825 . memorie sulla storia e notomia degli animali . senza verlebre del regno di napoli . i .

kramp , p . l . 1956 . pelagic fauna . p . 65 - 86 . in : ( a . bruun , sv . greve , h . mielche and r . spärck , eds . ) the galathea deep sea expedition 1950 - 1952 .

naef , a . 1921 / 23 . cephalopoda . fauna und flora des golfes von neapel . monograph , no . 35 .

nesis , k . n . 1982 / 7 . abridged key to the cephalopod mollusks of the world ' s ocean . 385 , ii pp . light and food industry publishing house , moscow . ( in russian . ) . translated into english by b . s . levitov , ed . by l . a . burgess ( 1987 ) , cephalopods of the world . t . f . h . publications , neptune city , nj , 351pp .

young , r . e . , m . vecchione and d . donovan . 1998 the evolution of coleoid cephalopods and their present biodiversity and ecology . south african jour . mar . sci . . , 20 : 393 - 420 .

page copyright © 2016 katharina m . mangold ( 1922 - 2003 ) , , and

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mangold ( 1922 - 2003 ) , katharina m . , michael vecchione , and richard e . young . 2016 . argonautidae

each tol branch page provides a synopsis of the characteristics of a group of organisms representing a branch of the tree of life . the major distinction between a branch and a leaf of the tree of life is that each branch can be further subdivided into descendent branches , that is , subgroups representing distinct genetic lineages .

for a more detailed explanation of the different tol page types , have a look at the structure of the tree of life page .

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linnaeus , c . ( 1758 ) . systema naturae per regna tria naturae , secundum classes , ordines , genera , species , cum characteribus , differentiis , synonymis , locis . editio decima , reformata . laurentius salvius : holmiae . ii , 824 pp . , available online at urltoken page ( s ) : 708 [ details ]

description mantle globular , as wide as long ; surface of mantle , head , arms , and web covered with conspicuous , closely - set , large , . . .

description mantle globular , as wide as long ; surface of mantle , head , arms , and web covered with conspicuous , closely - set , large , stellate tubercles ; a narrow , tuberculate , fold of skin encircles the lateral surface of the mantle ; funnel organ , 4 separate longitudinal pads . [ details ]

( of ocythoe antiquorum leach , 1817 ) leach w . e . ( 1817 ) . synopsis of the orders , families and genera of the class cephalopoda . the zoological miscellany ; being descriptions of new or interesting animals . 3 ( 30 ) : 137 - 141 . , available online at urltoken page ( s ) : 139 [ details ]

finn j . k . ( 2013 ) taxonomy and biology of the argonauts ( cephalopoda : argonautidae ) with particular reference to australian material . molluscan research 33 ( 3 ) : 143 - 222 . [ details ]

roper , c . f . e . , m . j . sweeney & c . e . nauen ( 1984 ) . fao species catalogue . vol 3 . cephalopods of the world . an annotated and illustrated catalogue of species of interest to fisheries . fao fish . synop . ( 125 ) , vol 3 : 277 p . [ details ]

branch , g . m . et al . ( 2002 ) . two oceans . 5th impression . david philip , cate town & johannesburg . , available online at urltoken [ details ]

spencer , h . g . , marshall , b . a . & willan , r . c . ( 2009 ) . checklist of new zealand living mollusca . pp 196 - 219 . in : gordon , d . p . ( ed . ) new zealand inventory of biodiversity . volume one . kingdom animalia : radiata , lophotrochozoa , deuterostomia . canterbury university press , christchurch . [ details ]

judkins , h . l . , m . vecchione , and c . f . e . roper . 2009 . cephalopoda ( mollusca ) of the gulf of mexico , pp . 701–709 in felder , d . l . and d . k . camp ( eds . ) , gulf of mexico–origins , waters , and biota . biodiversity . texas a & m ; press , college station , texas . [ details ]

rosenberg , g . 1992 . encyclopedia of seashells . dorset : new york . 224 pp . page ( s ) : 178 [ details ]

liu j . y . [ ruiyu ] ( ed . ) . ( 2008 ) . checklist of marine biota of china seas . china science press . 1267 pp . ( look up in imis ) [ details ] available for editors [ request ]

lu , c . c . & chung , w . s . ( 2017 ) . guide to the cephalopods of taiwan . national museum of natural science , taichung , taiwan , 560 pp . isbn 978 - 986 - 05 - 2569 - 4 . page ( s ) : 516 [ details ]

( of ocythoe argonautae cuvier , 1829 ) check list of european marine mollusca ( clemam ) . , available online at urltoken [ details ]

( of ocythoe antiquorum leach , 1817 ) finn j . k . ( 2013 ) taxonomy and biology of the argonauts ( cephalopoda : argonautidae ) with particular reference to australian material . molluscan research 33 ( 3 ) : 143 - 222 . [ details ]

gleadall , i . g . ( 1997 ) . hong kong cephalopada : a brief review of current knowledge and identification of specimens collected in 1995 . in : morton b , editor . proceedings of the eighth international marine biological workshop : the marine flora and fauna of hong kong and southern china . the marine flora and fauna of hong kong and southern china iv . hong kong university press , hong kong . 503 - 513 . [ details ]

to museum of new ze . . . [ hosted externally ; from synonym ]

likes to be near the surface of the water . it is an epipelagic oceanic species .

the maximum length of shell is 30 cm in females , but only 1 . 5 - 2 cm in males . the shell is coiled and laterally compressed with a narrow keel and numerous sharp nodules . nodules toward the center of the coil are brown , but most of the shell is white .

the male uses a specialized arm called a ' hectocotylus ' to fertilize the eggs . the hectocotylus is inserted into the females pouch and breaks off during mating . the female forms a " nacelle , " a thin calcareous shell , with two of her legs ( the others are used for swimming ) . this structure holds the eggs throughout development .

the female is up to twenty times larger than the male . normally these animals are solitary .

can be found in fish markets in india and japan . the shell is praised by collectors because of its beauty , coloration , sculpture , and fragility .

this animal is very common but is rarely spotted by humans . every once and a while many of them may be washed up by a change in currents or chased into shallow waters by predators , allowing people to observe and catch them .

the body of water between africa , europe , the southern ocean ( above 60 degrees south latitude ) , and the western hemisphere . it is the second largest ocean in the world after the pacific ocean .

body of water between the southern ocean ( above 60 degrees south latitude ) , australia , asia , and the western hemisphere . this is the world ' s largest ocean , covering about 28 % of the world ' s surface .

having body symmetry such that the animal can be divided in one plane into two mirror - image halves . animals with bilateral symmetry have dorsal and ventral sides , as well as anterior and posterior ends . synapomorphy of the bilateria .

the area in which the animal is naturally found , the region in which it is endemic .

structure produced by the calcium carbonate skeletons of coral polyps ( class anthozoa ) . coral reefs are found in warm , shallow oceans with low nutrient availability . they form the basis for rich communities of other invertebrates , plants , fish , and protists . the polyps live only on the reef surface . because they depend on symbiotic photosynthetic algae , zooxanthellae , they cannot live where light does not penetrate .

lane , frank . 1960 . kingdom of the octopus . sheridan house , new york .

roper , c . 1984 . cephalopods of the world . national museum , washington .

abbot , r . t . 1954 . american seashells . d . van nostrand co . , inc .

cousteau , jacques . 1973 . octopus and squid . doubleday and co . , new york .

disclaimer : the animal diversity web is an educational resource written largely by and for college students . adw doesn ' t cover all species in the world , nor does it include all the latest scientific information about organisms we describe . though we edit our accounts for accuracy , we cannot guarantee all information in those accounts . while adw staff and contributors provide references to books and websites that we believe are reputable , we cannot necessarily endorse the contents of references beyond our control .

this material is based upon work supported by the national science foundation grants drl 0089283 , drl 0628151 , due 0633095 , drl 0918590 , and due 1122742 . additional support has come from the marisla foundation , um college of literature , science , and the arts , museum of zoology , and information and technology services .

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argonauts occur in all tropical and temperate waters of the world . the exact number of species is not known . four species are currently recognised . the species are mainly distinguished by shell shape .

by well - developed connective apparatus conspicuous even in larvae . body firm , muscular ,

long , 1st much longer than others , 4th and 2nd shorter , 3rd are the shortest . fourth

10 - 20 % longer than 2nd , 1 . 5 - 2 times the length of 3rd . in maturing and mature females

present , photophores absent . twenty eight lamellae per demibranch in females . female builds characteristic thin , fragile calcareous

approx . 5 - 7 mm ; during subsequent life , beginning from approx . 8 mm ,

length . eggs very small ( 0 . 6 - 0 . 8 mm ) , laid and incubated in rear part of

wall . newborn larvae liberated by female probably every night . female begins to reproduce shortly after building

and continues to spawn eggs during entire life . males dwarfed , their 3rd left

everts and becomes much longer than male itself , detaches during mating . part of the

and remains there ; male dies after mating and is probably devoured by female . up to 3 hectocotyli may be found in one female . color of females purple - blue to wine - red from above , light from below ; extended 1st

not numerous ( < 35 ) , set far apart , nodules brown . fourth

much shorter than 2nd - 3rd , length in large females approx . 60 % of 2nd . egg size 0 . 7 - 0 . 8 mm . 20 lamellae per demibranch . a third

systema naturae per regna tria naturae , secundum classes , ordines , genera , species cum characteribus , differentiis , synonymis , locis .

sweeney , m . j . and c . f . e . roper / n . a . voss , m . vecchione , r . b . toll and m . j . sweeney , eds .

systematics and biogeography of cephalopods . smithsonian contributions to zoology , 586 ( i - ii )

turgeon , d . d . , a . e . bogan , e . v . coan , w . k . emerson , w . g . lyons , w . pratt , et al .

turgeon , d . d . , j . f . quinn , jr . , a . e . bogan , e . v . coan , f . g . hochberg , w . g . lyons , et al .

common and scientific names of aquatic invertebrates from the united states and canada : mollusks , 2nd ed .

taxon validity : [ fide robson ( 1932 : 181 ) ] . repository : ls syntypes . type locality : " pelago , m . indico , mediterrane "

disclaimer : itis taxonomy is based on the latest scientific consensus available , and is provided as a general reference source for interested parties . however , it is not a legal authority for statutory or regulatory purposes . while every effort has been made to provide the most reliable and up - to - date information available , ultimate legal requirements with respect to species are contained in provisions of treaties to which the united states is a party , wildlife statutes , regulations , and any applicable notices that have been published in the federal register . for further information on u . s . legal requirements with respect to protected taxa , please contact the u . s . fish and wildlife service .

this page was last edited on 16 may 2017 , at 00 : 41 .

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