I am very new to this site, and this is my first post, so please forgive me if I'm going over old ground.
[I was a professional biologist many years ago, mainly in genetics and evolutionary biology, but I never worked on cephalopods. I am now a Chaplain (Christian) at South Bank University in London, England, and am doing some part-time lecturing and tutoring to students on various biological courses. My knowledge of cephs. is minimal, but I hope to learn a lot more from the various experts posting on this site]
A dormant interest in cephs. being reawakened by the recent reports in the media on Mesonychoteuthis, I was very glad to find this website, and also the Tree of Life website.
From Kat Bolstad's article on "Deep Sea Cephalopods" on this site, I learn that the gut of Architeuthis dux has a maximum relaxed diameter of only 10mm. Is the implication here that Architeuthis can only eat relatively small prey?
What is known about the gut of Mesonychoteuthis? Is it much wider in diameter than that of Architeuthis?
Is there any real evidence as to the lifespan of these large squids? I read somewhere that cephalopods as a whole seem to have short lifespans, and that a very rapid growth rate is thereby implied for Architeuthis. What about Mesonychoteuthis?
There is a general rule that prey species are shorter-lived, and much more fecund, than their predators. It has been reported that the Patagonian Toothfish, which seems to be a very long-lived species, is a major part of the diet of Mesonychoteuthis. This might indicate that Meso. has a considerably longer basic life span than is typical for cephalopods.
Best wishes to all on this site.