Mesonychoteuthis--ammoniac or not?

Apr 4, 2003
This is probably a question for Steve O'Shea.

Is Mesonychoteuthis hamiltoni an ammoniac squid or not?

I'm referring to the use of ammonia for buoyancy, wondering if M. hamiltoni is thought to achieve near neutral buoyancy, like A. dux, or must swim constantly or sink, like loligo.


--Chris Slaybaugh
I'll give a somewhat preliminary answer, as we haven't done any chemical analysis on the tissues yet, and Steve's off gallavanting around Auckland for the weekend...
One of the first things we noticed about this Mesonychoteuthis specimen was that it didn't smell anything like a giant squid. The strong ammonia smell of a dead Architeuthis is not only unmistakable when you first get a whiff... it also continues to be unmistakable days later when it starts oozing out of your skin, and weeks later in your clothes, and MONTHS later in your car (you think I'm kidding!!!)...
So just to do a follow-up stink test on our initial impression, Steve left his clothes out overnight (as opposed to immediately throwing them into a tub with about 8 boxes of baking soda) and, lo and behold, they didn't even stink the NEXT day.
So based on those very scientific analyses :wink: if the tissues are ammoniacal, they are far less so. We have also been thinking about probable behavior / locomotion in Mesonychoteuthis and, based on the size and muscularity of the fins, we think it's moving pretty fast and would have little need for buoyancy.
But again, that's only a guess. We'll keep you posted as we find out more.
It strikes me as likely that an animal so obviously evolved into a potent predator would be muscle-powered rather than float around in an ammonia life jacket. :smile: Maybe they're like sharks, always moving... although I suppose they could rest on the bottom? I don't know enough about their respiration to know if that's likely or not.

Maybe they even sleep on the move. They could just turn on the cruise control and take a nap in the deep. Not like you're gonna run into anything, unless a sperm whale wrecks your beauty sleep.
We never tested for ammonium ions (relative to sodium), but this animal did not smell at all (unlike a day-old Architeuthis, post defrost). I'm inclined, although cannot be sure, to think that this animal is not ammoniacal (or at least nowhere near as ammoniacal as Architeuthis).

I'll post some interesting information about the ammonium/sodium ion ratios in Architeuthis shortly - it's quite staggering.

Thanks, gents, for the very useful info.

I'm going on holiday for a couple of weeks, so though any followups will be appreciated, it will be a while before I get them.


I am probably wrong about this but I thought that the cranchiid squids retained ammonia ions in a special vertically orientated organ usually located towards the rear of the body. Are we saying that this organ is not present in this specimen? If so, is Mesonychoteuthis a true cranchiid?

I really don't know what physical characteristics define the cranchiid family of squids, aside from this organ, but if it is not present would Mesonychoteuthis perhaps have to be reclassified?

Just thoughts.......
Sorry about the delayed response, I had to do a little research on this one... :smile:

Mesonychoteuthis is currently accepted as a cranchiid, and of the following characteristics, the ones we looked at checked out.

Cranchiids are characterised by the following:

- Mantle fused with the funnel and head in the occipital area (yes)
- Buccal membrane with six lappets (DDVV) (yes)
- Photophores present on eyeball (several round or 1-2 elongated) (yes)

Also (the theory goes): "Characteristic to the family is a spacious closed body cavity (coelom) containing a considerable quantity of NH4Cl solution. Density of this solution is lower than sea water, so the coelom serves as a float that maintains the squid in a state of neutral buoyancy ('bathyscaphoid squids'). A horizontal membrane divides the mantle cavity into an upper (containing the coelom) and lower part communicating by two round openings - the spiracles, located above the gills; the respiratory flow of water passes posteriorly along the upper chamber on both sides of the coelom, then through the spiracles, over the gills,forward to the head and out through the funnel." (Nesis 1987)

We don't know anything about Mesonychoteuthis' buoyancy yet, and we do know that the insides of this specimen are considerably damaged.

I also found this on Tree of Life: "The ability of cranchiids to maintain the digestive gland in a vertical orientation can be seen the the adjacent photographs." (See this page and this page).

So... I think it's the digestive gland that's vertically oriented (half within the coelom, half outside), but just the coelom in general that encloses the NH4Cl. And on a side-note, that Taonius is one of the freakiest-looking squid I've ever seen.

I know I learned something new today... :wink:

Nesis, K.N. 1987. Cephalopods of the world (English translation). Tropical Fish Hobbyist (T.F.H.) publications, Neptune City. 1–352.

Thanks for looking this definition of a cranchiid and letting us know.

Now I have a few more very long and tedious questions for you......... :shock:

Not really relevant to this thread, but if anyone finds themselves a giant squid (or any squid) and wants to determine if the tissues are ammoniacal, here's a quick test (that doesn't involve taste buds).

Cut a small piece (~ 1 cm cubed) of tissue and place it into a narrow-necked flask (test tube or other such glass container). Add several crystals of caustic potash (potassium hydroxide), heat the container, and then sniff emissions for any ammonia vapour.

....if it is present you'll know; wish I'd remembered when we had the colossal out and fresh :roll:
Steve O'Shea said:
Not really relevant to this thread, but if anyone finds themselves a giant squid (or any squid) and wants to determine if the tissues are ammoniacal, here's a quick test (that doesn't involve taste buds).

no worries....its relevent.... how strongly would you advise against the taste bud method? even if money and/or honor is on line? :smile: