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Argonauta

GPO87

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#1
Commonly known as the paper nautilus, Argonauts are octopods which secrete a thin calcareous shell around their mantle. There are 4 known species in the genera. They can get moderately large, with shells reaching a diameter of up to 30 cm.



Info at: http://tolweb.org/Argonautidae/20204
 

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Tentacle Toast

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My day is brightened..do you just do image searches? This is two threads now with wicked pix. I've gotta tell ya, TONMO is great to check in the mornings, but it leaves you daydreaming all day...
 

DWhatley

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Biological and environmental signals recorded in shells of Argonauta argo(Cephalopoda, Octobrachia) from the Sea of Japan
Kevin Stevens, Yasuhiro Iba, Akihiko Suzuki, Jörg Mutterlose

Abstract
The argonauts (genus Argonauta) are enigmatic cephalopods. They have a cosmopolitan distribution in subtropical and tropical seas, where they inhabit the epipelagic zone. Their biology, ecology, and life cycle are poorly understood. It is for the first time that stable isotope (δ13C, δ18O) and element ratios (Mg/Ca, Sr/Ca, Ba/Ca) from three argonaut shells have been analyzed in order to test whether their life cycle and habitat are reflected in these data. The three studied shells have been collected in October 2012 from a mass stranding in Yoichi Bay, Hokkaido, Japan. The specimens were sampled along the keel of the shells to acquire ontogenetic records and along growth-sections of the shells to obtain synchronous data of differing shell growth rates. Carbon and oxygen isotope values as well as Mg/Ca ratios are in part controlled by the shell growth rate. Sr/Ca values show similar ontogenetic trends in the three shells. Comparison with measured sea surface temperature data indicates a temperature control on δ18O, Mg/Ca, and Sr/Ca, and a fast growth of the argonaut shell. Ba/Ca ratios of the shells might record environmental parameters. These new data highlight the influence of vital effects, but they also demonstrate that argonaut shell isotopic and elemental records can be used to understand the life cycle of these animals better.
 

DWhatley

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DWhatley

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Scientists solve millennia-old mystery about the argonaut octopus
Not Exactly Rocket Science Ed Yong 2010

... Into this debate came Finn and Norman. Their names may be familiar to regular readers – they have discovered the smash-hit octopus that carries coconut shells as a suit of armour, dolphin chefs that can prepare a cuttlefish meal, and the awesome mimic octopus. As with these earlier discoveries, their work on argonauts was based on observations of wild animals. They rescued three greater argonauts (Argonauta argo) from nets in the Sea of Japan, released them into Okidomari Harbour and filmed them as they adjusted to their freedom. It’s their beautiful video that graces the top of this post. ...
 

DWhatley

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Australian Survey

(check out the link for more)
There is still very little known of the distribution, biology and behaviours of argonauts. Through funding by the Hermon Slade Foundation and Australian Biological Resources Survey, Museum Victoria is undertaking a detailed survey of argonauts in Australian waters.



A live female argonaut (Argonauta nodosus) with shell-secreting webs covering the outside of the shell. Photo: © Rudie Kuiter

This survey is reviewing the species that occur in Australian waters, their distributions, their roles in oceanic food webs, data on strandings, and where possible, live animal observations.

At this stage, three species are confirmed from Australian waters:

Knobbed Argonaut (Argonauta nodosus)

Distribution: known from southern Australia - from New South Wales to Tasmania and South Australia

Greater Argonaut (Argonauta argo)

Distribution: known from southern Western Australia. Shells occasionally collected in South Australia, Victoria, Tasmania, New South Wales and Queensland.

Lesser Argonaut (Argonauta hians)

Distribution: known from northern Australia - from the North West Shelf of Western Australia to Queensland . Shells occasionally collected in New South Wales.
 

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