Information about Knobby Argonaut

Knobby Argonaut
Eggcase of Argonauta nodosa
Scientific classification
Kingdom: Animalia Phylum: Mollusca Class: Cephalopoda Order: Octopoda Family: Argonautidae Genus: Argonauta Species: A. nodosa
Binomial name
Argonauta nodosa Lightfoot, 1786
Synonyms
?Argonauta oryzata Meuschen, 1787 Argonauta tuberculata Roding, 1798 Argonauta tuberculosa Lamarck, 1822 in 1815-1822 Argonauta gracilis Kirk, 1885

The Knobby or Knobbed Argonaut (Argonauta nodosa) is a species of pelagic octopus. 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 shell is usually approximately 150 mm in length, although it can exceed 250 mm in exceptional specimens; the world record size is 292.0 mm.^[1] A. nodosa produces a very characteristic shell, which is covered in many small nodules on the ridges across the shell, hence the specific epithet nodosa and common name. These nodules are less obvious or even absent in juvenile females, especially those under 5 cm in length.^[2] All other argonaut species have smooth ridges across the shell walls.^[2]



A. nodosa has a relatively wide distribution covering the Indo-Pacific region as well as the eastern coast of South America. The species is most common in southern Australia, New Zealand, and South Africa.^[2] It is only known from the Southern Hemisphere.^[3]

A. nodosa is thought to feed primarily on pelagic molluscs. Captive females have been observed readily taking dead prawns and fish.^[2] The species is preyed on by numerous predators. It has been reported in the stomach contents of Alepisaurus ferox from the south-western Pacific.^[4] A. nodosa has also been found in the stomach contents of Australian Fur Seals, Arctocephalus pusillus doriferus, in the Bass Strait and southern Tasmania.^[5]

Females grow to 100 mm ML and 300 mm total length, while males do not exceed 40 mm in length.^[2] The specialised webbed arm pair of this species is covered in numerous chromatophores. Mark Norman notes that "the colour of these webs can quickly change from maroon red to reflective silver".^[2]

It has been reported that the egg clusters of A. nodosa from southern Australia can be clearly divided into three portions, each with eggs at a similar developmental stage.^[6] Similar development has been observed in the egg masses of Argonauta bottgeri.^[7]

A. nodosa 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.

The type specimen of A. nodosa was collected off the Cape of Good Hope. The type repository is unknown.^[8]

Female A. nodosa with eggcase removed

Female A. nodosa with eggcase present

References

1. ^ Pisor, D. L. (2005). Registry of World Record Size Shells, 4th edition, Snail's Pace Productions and ConchBooks, p. 12. 
2. ^ Norman, M. (2000). Cephalopods: A World Guide. ConchBooks, p. 192. 
3. ^ Lu, C. C.. Argonautidae. Australian Biological Resources Study. Retrieved on 2006-09-13.
4. ^ (French) Rancurel, P. (1970). "Les contenus stomacaux d' Alepisaurus ferox dans le sud-ouest Pacifique (Céphalopodes)". 'Cah. O.R.S.T.O.M. Ser. Océanogr. 8 (4): 4-87. 
5. ^ Gales, R., D. Pemberton, C. C. Lu & M. Clarke (1994). "The cephalopod diet of the Australian fur seal: variation due to location, season and sample type". Aust. J. Mar. Freshwater Res. 44': 657-671. 
6. ^ Reid, A. (1989). "Argonauts: ancient mariners in boats of shell". Aust. Nat. Hist. 22 (12): 580-587. 
7. ^ Nesis, K. N. (1977). "The biology of paper nautiluses, Argonauta boettgeri and A. hians (Cephalopoda, Octopoda), in the western Pacific and the seas of the East Indian Archipelago". Zool. Zh. 56: 1004-1014. 
8. ^ Current Classification of Recent Cephalopoda

• Sweeney, M. J. (2002). Taxa Associated with the Family Argonautidae Tryon, 1879. Tree of Life web project.

External link

• CephBase: Knobby Argonaut
• Tree of Life web project: Argonauta

Argonauta species

A. argo • A. bottgeri • A. cornuta • A. hians • A. nodosa • A. nouryi • A. pacifica

Scientific classification or biological classification is a method by which biologists group and categorize species of organisms. Scientific classification also can be called scientific taxonomy, but should be distinguished from folk taxonomy, which lacks scientific basis.
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Mollusca
Linnaeus, 1758

Classes

Caudofoveata
Aplacophora
Polyplacophora
Monoplacophora
Bivalvia
Scaphopoda
Gastropoda
Cephalopoda
† Rostroconchia
† Helcionelloida
† ?Bellerophontida
The molluscs
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Cephalopoda
Cuvier, 1797

Orders

Subclass Nautiloidea

• †Plectronocerida
• †Ellesmerocerida
• †Actinocerida
• †Pseudorthocerida
• †Endocerida
• †Tarphycerida
• †Oncocerida

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Octopoda
Leach, 1818

Suborders

†Pohlsepia (incertae sedis)
†Proteroctopus (incertae sedis)
†Palaeoctopus (incertae sedis)
Cirrina
Incirrina
Synonyms

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Argonautidae
Tryon, 1879

Genera

Argonauta
†Izumonauta
†Kapal
†Mizuhobaris
†Obinautilus

Argonautidae
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Argonauta
Linnaeus, 1758

Species

†Argonauta absyrtus
Argonauta argo (type)
Argonauta bottgeri
Argonauta cornuta*
Argonauta hians
†Argonauta itoigawai
†
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binomial nomenclature is the formal system of naming species. The system is also called binominal nomenclature (particularly in zoological circles), binary nomenclature (particularly in botanical circles), or the binomial classification system.
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The Reverend John Lightfoot (1735-1788) was an English conchologist and botanist.

Lightfoot was the chaplain and librarian of Margaret Bentinck, Duchess of Portland.
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In scientific nomenclature, synonyms are different scientific names used for a single taxon. Usage and terminology are different for zoology and botany.

Zoology

In zoological nomenclature, synonyms are different scientific names that pertain to the same taxon, for example
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species is one of the basic units of biological classification. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring.
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The pelagic zone is the part of the open sea or ocean that is not near the coast. In contrast, the neritic zone comprises the water that is near to (and is significantly affected by) the coast or the continental shelf.
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Octopoda
Leach, 1818

Suborders

†Pohlsepia (incertae sedis)
†Proteroctopus (incertae sedis)
†Palaeoctopus (incertae sedis)
Cirrina
Incirrina
Synonyms

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Argonauta
Linnaeus, 1758

Species

†Argonauta absyrtus
Argonauta argo (type)
Argonauta bottgeri
Argonauta cornuta*
Argonauta hians
†Argonauta itoigawai
†
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A. argo

Binomial name
Argonauta argo
Linnaeus, 1758

Synonyms

• Argonauta papyracea
  Roding, 1798
• Argonauta grandiformis
  Perry, 1811
• ?Argonauta striata

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An epithet (Greek — επιθετον and Latin — epitheton; literally meaning 'imposed') is a descriptive word or phrase that has become a fixed formula.
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See also Wikipedia:Naming conventions (common names) and Wikipedia:Naming conventions

In science, a common name is any name by which a species or other concept is known that is not the official scientific name.
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In biology, the range or distribution of a species is the geographical area within which that species can be found.

The term is often qualified:

• sometimes a distinction is made between a species' native range

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Indo-Pacific is a biogeographic region of the earth's seas, comprising the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the seas connecting the two in the general area of Indonesia.
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South America is a continent of the Americas, situated entirely in the Western Hemisphere and mostly in the Southern Hemisphere. It is bordered on the west by the Pacific Ocean and on the north and east by the Atlantic Ocean; North America and the Caribbean Sea lie
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Anthem
Advance Australia Fair ^[1]

Capital Canberra

Largest city Sydney
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Anthem
"God Defend New Zealand"
"God Save the Queen" ¹

Capital Wellington

Largest city Auckland
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Southern Hemisphere or southern hemisphere^[1] is the half of a planet that is south of the equator—the word hemisphere literally means 'half ball'. It is also that half of the celestial sphere south of the celestial equator.
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Mollusca
Linnaeus, 1758

Classes

Caudofoveata
Aplacophora
Polyplacophora
Monoplacophora
Bivalvia
Scaphopoda
Gastropoda
Cephalopoda
† Rostroconchia
† Helcionelloida
† ?Bellerophontida
The molluscs
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Dendrobranchiata
Bate, 1888

Superfamilies and families

Penaeoidea

Aristeidae

Benthesicymidae

Penaeidae

Sicyoniidae

Solenoceridae

Sergestoidea

Luciferidae

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Alepisauridae

Genus: Alepisaurus
Lowe, 1833

Species: A. ferox
A.
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A. pusillus

Binomial name
Arctocephalus pusillus
(Schreber, 1775)

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Bass Strait (IPA: /bæs/) is a sea strait separating Tasmania from the south of the Australian mainland (Victoria in particular). The first European to discover it was Matthew Flinders in 1798.
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