...elsewhere in the forums ob brought up the 1981 Meso specimen caught by a Russian trawl. We were discussing Mesonychoteuthis eyes. The '81 squid's eyes look very well-preserved...which is amazing, when you consider that the squid was trawled. The mantle and arms look as banged-up as you'd expect, but the visible portion of the head hasn't suffered nearly so much abuse. Trying to account for the high level of preservation of the most delicate parts, I recalled Steve's earlier post. The photo of the '81 Meso suggests to me that large sub-adults are capable of retracting the head into the mantle cavity, and that's what this squid did when the trawl hit it.Steve O'Shea;8683 said:Cranchiid squid like Teuthowenia can pull their head entirely within their mantle, inking within the mantle and appearing like grapes (this is actually what I thought we had in one sample several years ago - deep-sea 'grapes'). As the eyes of Mesonychoteuthis have photophores, perhaps this animal can also withdraw the head (and arms) within the mantle ... ouch ... and the black lining of the mantle wall conceals any bioluminescence from the eyes. You still have to have a large-enough predator to warrant this behaviour, however. Perhaps the smaller animals need to be able to do so, and the character state is just carried forth through to the adult (where it isn't really required, but is a non-lethal behavioural attribute ... as in it doesn't harm the animal to be able to do so, rather than it being advantageous to be able to do so).
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