Английская Википедия:Hectocotylus

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Шаблон:Short description

Файл:Hectocotyle1.jpg
Georges Cuvier's original illustration of an octopus hectocotylus, which he named Hectocotyle octopodis

A hectocotylus (Шаблон:Plural form: hectocotyli) is one of the arms of male cephalopods that is specialized to store and transfer spermatophores to the female.[1] Structurally, hectocotyli are muscular hydrostats. Depending on the species, the male may use it merely as a conduit to the female, analogously to a penis in other animals, or he may wrench it off and present it to the female.

The hectocotyl arm was first described in Aristotle's biological works. Although Aristotle knew of its use in mating, he was doubtful that a tentacle could deliver sperm. The name hectocotylus was devised by Georges Cuvier, who first found one embedded in the mantle of a female argonaut. Supposing it to be a parasitic worm, in 1829 Cuvier gave it a generic name,[2][3][4][5] combining the Greek word for "hundred" and Latin word for "hollow thing, cup".

Structure

Generalized anatomy of squid and octopod hectocotyli: Шаблон:Multiple image Шаблон:Clear left

Variability

Hectocotyli are shaped in many distinctive ways, and vary considerably between species. The shape of the tip of the hectocotylus has been much used in octopus systematics.

  • Many coleoids lack hectocotyli altogether.[6]
  • Among Decapodiformes (ten-limbed cephalopods), generally either one or both of arms IV are hectocotylized.
  • In incirrate octopuses, it is one of arm pair III.[6] Rare examples of double and bilateral hectocotylization have also been recorded in incirrate octopuses.[7][8]
  • In male seven-arm octopuses (Haliphron atlanticus), the hectocotylus develops in an inconspicuous sac in front of the right eye that gives the male the appearance of having only seven arms.
  • In argonauts, the male transfers the spermatophores to the female by putting its hectocotylus into a cavity in the mantle of the female, called the pallial cavity. This is the only contact the male and female have with each other during copulation, and it can be at a distance. During copulation, the hectocotylus breaks off from the male. The funnel–mantle locking apparatus on the hectocotylus keeps it lodged in the pallial cavity of the female.
Shape of hectocotylus Species Family
Файл:Abraliopsis morisi hectocotylus-English.jpg Abraliopsis morisi Enoploteuthidae
Файл:Argonauta bottgeri hectocotylus-2.jpg Argonauta bottgeri Argonautidae
Файл:Bathypolypus arcticus hectocotylus-2.jpg Bathypolypus arcticus Octopodidae
Файл:Graneledone verrucosa hectocotylus.jpg Graneledone verrucosa Octopodidae
Файл:Haliphron atlanticus hectocotylus.jpg Haliphron atlanticus Alloposidae
Файл:Ocythoe tuberculata hectocotylus.jpg Ocythoe tuberculata Ocythoidae
Файл:Scaeurgus patagiatus hectocotylus-2.jpg Scaeurgus patagiatus Octopodidae
Файл:Tremoctopus violaceus5.jpg Tremoctopus violaceus Tremoctopodidae
Файл:Uroteuthis duvauceli hectocotylus.jpg Uroteuthis duvauceli Loliginidae

References

Шаблон:Commons category Шаблон:Reflist

Шаблон:Cephalopod anatomy

  1. Шаблон:Cite book
  2. Шаблон:Cite book
  3. Шаблон:Cite book
  4. Шаблон:Cite book
  5. Шаблон:Cite web
  6. 6,0 6,1 Young, R.E., M. Vecchione & K.M. Mangold (1999). Cephalopoda Glossary. Tree of Life Web Project.
  7. Robson, G.C. 1929. On a case of bilateral hectocotylization in Octopus rugosus. Journal of Zoology 99(1): 95–97. Шаблон:Doi
  8. Palacio, F.J. 1973. Шаблон:Cite web The Nautilus 87: 99–102.