CLASSIFICATION OF ARGONAUT (PAPER NAUTILUS)
KINGDOM :- ANIMALIA (Multicellular eukaryotic organisms)
PHYLUM :- MOLLUSCA (Unsegmented bilaterally symmetrical and provided with visceral mass, foot and mantle.)
CLASS :- CEPHALOPODA (Head well developed with eyes and radula. Foot represented by arms and tentacles.)
ORDER :- Octopoda (Shell and tentacles absent. Arms eight.)
FAMILY :- ARGONAUTIDAE
GENUS :- Argonaut
It is distributed in Atlantic and Indian oceans and also found in tropical parts of the Pacific ocean.
HABIT AND HABITAT
It is a marine cephalopod.
GENERAL CHARACTERSTICS OF ARGONAUT (PAPER NAUTILUS)
- Commonly called as ‘Paper Nautilus’. It is actually not a Nautilus but is more closely related to Octopus.
- Sexual dimorphism is commendable. Male is approximately 25 cm long and without shell while female is about 25 cm long and possess characteristic external shell.
- Shell is thin symmetrical, spiral without septa secreted by terminal expansions of two specialized dorsal arms called as Sail or Vela.
- Shell carries eggs, the name ‘Paper Nautilus’ refers to the thinness and fragility of dry shell.
- Third arm in the male is hectocotylised and used for conveying spermatophores into the mantle cavity of the female. It can be entirely separated from the male and left in the mantle cavity of the female.
- Funnel protrudes between arms.
The animal contains sail and all above characters, hence it is Argonauta.