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Hooks & suckers

17 July 2008 – 4.04pm

The hooks seem to grab everyone’s attention, so here’s an update

tentacle club swivelling hook and arm sucker

tentacle club swivelling hook and arm sucker dissected out from the fleshy suckers

Other squid families have hooks on the arms, or the tentacles, or both, but the colossal squid is the only hooked squid in its family (the Cranchiidae, about 20 species). It possesses hooks on each of the eight arms, and also on the club ends of the two long tentacles, but the arm-hooks and tentacle-hooks are very different.

The tentacular hooks are the swivelling hooks. Each sits on a short stalk, flush with the oral surface of the tentacle club, in a flattened depression that allows the flattened ‘back’ surface of the hook to rotate. The hooks can swivel 360 to 720 degrees, but it is not known whether the squid actively controls each hook individually, or whether the hooks swivel passively once latched onto the prey, in order to keep the best grip. There are 22 to 25 hooks in two rows on the middle part (manus) of the tentacle club, and each row is flanked by a row of tiny marginal suckers. The swivelling hooks are smaller than those on the arms and have only a singe main ‘claw.’

 

 

The arm hooks do not swivel. They are set in a double row in the middle of each arm, preceded and followed by the more standard toothed suckers. The arm hooks are set in fleshy, very muscular sheaths and are strongly attached to the arms. They are likely to assist in holding and immobilising struggling prey as it is being killed and eaten. Most of the arm hooks have the main strong ‘claw’, and also two smaller auxiliary cusps closer to the hook’s base, making them three-pointed and maximising their ability to hold and dig in. The base of each hook also has a complex structure that is set deep into the surrounding musculature.  The top picture shows the hook and serrated sucker im structure dissected out from the fleshy part of the suckers.

Non-swivelling arm hooks

Non-swivelling arm hooks

 

 

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Getting tanked

24 June 2008 – 1.02pm

Getting the colossal squid onto display isn’t just a simple matter of building a tank and moving it into the gallery!

First of all we have to plan a few details – for example, because of the size of the tank and the amount of liquid it will contain, it will weigh over five tonnes, so the building engineers have to check that the floor loadings will cope.

Then we have to consider how to get the tank into the building once it is built – it may be too wide to fit through the door, so exhibition staff will have to decide if it can be lifted into the building through a window using a crane – fortunately the museum was designed with these issues in mind, so there are windows which can be removed relatively easily to do this (we’re hoping that  Wellington’s balmy weather won’t cause any delays).

Once the tank is in place we have to fill it with preservative. 5,000 litres of preservative will have to be mixed and pumped into the tank – that’s about 25x 200 litre drums which will have to be transported into the gallery and mixed to the correct concentration in the tank – something which will have to be done when the museum is closed to the public.

In the event of an earthquake there is the risk of the tank rupturing, so to prevent a tidal wave of preservative cascading through the collections, the entire floor of the gallery has to be bunded to contain any spillage – this will involve a complete rebuild of the gallery floor!  

As the gallery is a public space we cannot use the usual formalin or alcohol preservatives, but will be trialling a propylene-glycol mixture. (Glycol is used as anti-freeze and has been used previously to preserve specimens on a smaller scale, but we will need to design the tank so that we can take samples for testing on a regular basis to check the pH for acidity and any signs of deterioration of the specimen). 

Placement of the specimen inside the tank will require the construction of some supports to keep it in place – because of the different density of parts of the specimen, some parts, such as the mantle, will float upwards, while others, such as the arms, will sink.

While preparations are underway to get the tank built, designers are working on how to light the specimen so that it can be seen: we are going to use an LED system which will enable lights to be placed inside the tank to avoid problems of reflection from the liquid surface. Then there’s the supporting display with other specimens and photographs to be prepared and labels written, printed and installed.

Not to forget the squid itself! We are still planning on how to lift 495 kg of pickled  squid out of its temporary fixing tank, into the display tank and move it from the laboratory building (about 1 kilometre away) to Cable Street. The preservation process has made the tissues much stronger and less jelly-like, but so far we haven’t been able to even turn it over to see what condition it is in without the risk of tearing the mantle.

So far things are going to plan – we hope to have a date for the display before the end of the year.

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Lectures available

22 May 2008 – 3.09pm

Two of the lectures from the Te Papa squid lecture series are now available online:

Dr Steve O’Shea
Squid: Small, Giant, and Colossal 
http://www.r2.co.nz/20080520/steve.asx

Dr Eric Warrant and Dr Dan-Eric Nilsson:
The Weird and Wonderful Eyes of Animals Who Live in the Dark and the Deep Sea
http://www.r2.co.nz/20080520/eric.asx

 

 

We will unfortunately not be able to have other lectures online due to copyright issues.

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What’s next?

5 May 2008 – 3.40pm

We’ve had time to catch up on a few things today . . . the lab is almost cleared of our equipment and Anton has begun moving things in for tomorrow’s dissection of a juvenile pygmy right whale.

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The fix is in

3 May 2008 – 11.14am

Here we are adding formalin to the storage tank to bring the concentration up to 5%. The formalin is then buffered to stop any acidity corroding the hooks of the specimen.

A plastic liner is placed over the top of the tank before the wooden lid is replaced.

Finally the pH (acidity) is checked – it will be checked every three days until the specimen is fully fixed at the end of the month.

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Murky water

2 May 2008 – 9.57am

Several people have asked why the water went from a clean, clear, inviting bath to a rather horrible-looking soup over the course of the squid defrosting. 

Clean tank Murky water

The answer is that a number of frozen fluids in the ice block were gradually released into the brine. The first unsalubrious additive was a yellow slurry of fish waste that had gotten mixed into the ice cake on top of the squid, in a layer about 10cm thick. As we examined and dissected the smaller colossal and the giant squid, some of their body fluids (ink and leakage from the digestive gland – sorry you asked yes?) also inevitably got mixed into the main tank from our waders, in spite of being rinsed. 

Because we have not dissected the large colossal specimen, we don’t know what condition its internal organs are in, but it is likely that similar fluids (in higher volumes) would also have been released into the brine as it defrosted, plus haemolymph (the squid’s blue, copper-based ‘blood’). 

As a cranchiid, Mesonychoteuthis also possesses a large sac within the mantle (the coelom) filled with ammonium chloride to assist its buoyancy.  This may also have leaked into the tank.  Finally, by the time the innermost ice had melted, the outermost parts of the specimen had been defrosted for over 36 hours and had entered the very early stages of decomposition.  The bacteria present would have begun to break down the tissues and also release chemicals and compounds into the water. 

This does not mean, however, that parts of the specimen have rotted – we were able to add the formalin at a time when all parts of the squid were thawed and in good condition.  If the squid had defrosted in air, the outer parts would certainly have rotted before we even saw the inside, so the cooled brine solution worked well – even if we had to wade through squid soup by the end.  :)

- Kat Bolstad

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Good night and good luck

30 April 2008 – 9.36pm

The Kraken

Below the thunders of the upper deep,
Far far beneath in the abysmal sea,
His ancient, dreamless, uninvaded sleep
The Kraken sleepeth: faintest sunlights flee
About his shadowy sides: above him swell
Huge sponges of millennial growth and height;
And far away into the sickly light,
From many a wondrous grot and secret cell
Unnumbered and enormous polypi
Winnow with giant fins the slumbering green.
There hath he lain for ages and will lie
Battering upon huge seaworms in his sleep,
Until the latter fire shall heat the deep;
Then once by men and angels to be seen,
In roaring he shall rise and on the surface die.
Alfred, Lord Tennyson
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B.T.W. – it’s a girl

30 April 2008 – 9.18pm

We just found the ovaries – the specimen is a girl!

Here’s an image from the microscope video (x150) – showing a bunch of eggs….the ovaries are full of several thousands of eggs!

Eggs of the colossal squid

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Formalin fixing

30 April 2008 – 9.05pm

The specimen is thawed and we now have to add formalin to preserve it – as formalin is toxic the scientists have to wear full protective gear while pumping 600 litres into the tank. The smaller specimen is being preserved by injecting 3% formalin into the tissue. Once the formalin has been pumped into the tank, we will replace the lid and head off home for a good night’s sleep. For those of you still watching I understand that some recorded footage from today will be screening for a while this evening.

The plastic lid will be put over the tank, then the wooden lid. Steve O’Shea and Mark Fenwick will be here all night monitoring the pH at 3 hourly intervals – and adding bicarbonate to keep it as neutral as possible so that the hooks and beak don’t dissolve.

Cheers. Thanks for watching

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2400 watching the lab right now

30 April 2008 – 7.30pm

The crew in the lab waved to acknowledge your phenomenal support!

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