Friday mystery object #403 answer

Last week I gave you this rather beautiful mystery object from my old place of work, the Horniman Museum:

It’s the only example I’ve seen of this species that’s been prepared to show it from this perspective – and it’s pretty special. There were plenty of answers, with most people on the button with the what it’s from.

Goatlips was the first to jump in with the broader identification, but palfreyman1414 was first to get the the species. The highly reflective, pearly surface (comprised of mother-of-pearl or nacre) provides a bit of a clue. This is a transverse section of a Pearly or Chambered Nautilius Nautilus pompilius Linnaeus, 1758.

Normally when people take sections through a Nautilus they take a sagittal section, to show the near perfect logarithmic spiral formed by the shell as it grows, so the transverse section offers a perspective that’s much less familiar:

Image of *Nautilus* shell in sagittal section taken by Chris 73, 2004

Since the transverse section is so unusal it’s quite difficult to find good references for identification. However, with a good imagination you can work out what’s going on with the relative sizes of the chambers and how much they overlap, to get a sense of the shape in the coronal plane (that’s the line through the body that gives us a transverse section).

That said, it’s easy to recognise that this shell is from the genus Nautilus rather than Allonautilus thanks to this image from Jereb and Roper, 2005:

Shell characters of genus *Nautilus* vs. genus *Allonautilus*. After Jereb and Roper (2005), modified by Antonov, 2008

There is also a paper by Ward and Sanders, 1997 with the same sections shown, plus an additional illustration of N. macromphalus which lacks the thick side walls seen in N. pompilius. From what I’ve seen I’m reasonably happy that the specimen is a Pearly Nautilus, but the taxonomy of this ancient group of cephalopods is still quite poorly known, so I’ll hang on to a shred of doubt for a while.

Friday mystery object #322 answer

Last week I gave you this new acquisition for the Dead Zoo to identify:

mystery322

It’s a detail of something large, and it had a lot of you stumped because it looks like a cross between a marble worktop and pork terrine.

However, if you look closely at the bottom left of the image, you may just be able to make out the shape of a sucker-covered arm, because this – as spotted by palfreyman1414 and jennifermacaire – is a big cephalopod.

When I say big, I mean it’s the second largest species after the Colossal Squid (that I’ve talked about before) – that’s right, it’s a view of part of a large ice cube containing a Giant Squid Architeuthis dux Steenstrup, 1857.

Squid holding sailor by Alphonse de Neuville & Édouard Riou, from Hetzel edition of 20000 Leagues Under the Sea, p. 400.

This individual isn’t actually particularly giant, measuring in at a meagre 5.8m, including its long thin feeding tentacles – quite big, but hardly Kraken-esque. It was caught 118 miles off the Kerry coast after it found its way into shallower waters than the abyssal depths they normally inhabit. You can see details of how it was caught and a photo of the specimen on the Irish Times website.

I haven’t started the process of preserving for the long term yet, as it will require a bit of time to release the kraken from the ice, a large tank and some nasty chemicals – namely a 10% formalin solution and various strengths of Industrial Methylated Spirits (IMS – which is adulterated alcohol), stepping up to 70% in 10-20% increments. I may also need include an alkali buffer in the tank (marble chips are commonly used) since Giant Squid use ammonium chloride in their tissues to increase their buoyancy and that can acidify the solution, leading to accelerated bleaching of the tissues and long-term damage to the specimen.

Even with good preservation it’s unlikely to ever go on display as a full specimen. I can probably find a big enough jar, but the specimen has been dissected and isn’t really looking its best. However, it may be worth showing some of the elements, like an eye, the beak or maybe an arm or tentacle. These may be in good enough condition to use on display to explain some of the interesting features of these denizens of the deep. The rest of the squid will be there for researchers interested in these large, but elusive, molluscs.

Friday mystery object #296

This week I’ve been in the USA couriering a loan back from the stunning Corning Museum of Glass (I’ll write about that sometime soon). However, that means I’ve had limited access to specimens for this week’s mystery object and I’m restricted to what I’ve got on my phone. Fortunately, I have this non-vertebrate mystery object for you to try your hand at identifying to species:

mystery296

It’s quite a cool specimen and I’ll tell you why next week! Have fun!

Friday mystery object #200 answer

Last week I gave you this object to identify:

It was a bit of a mean one, since it had no scale bar and the specimen is quite old and dried out, so it doesn’t look much like the living animal.

I had hoped that this would mean that nobody would manage to identify it, but I wasn’t at all surprised when correct suggestions started coming in.

Dave Hone was the first to get the correct kind of animal, although he was a bit thrown by the outer surface – vannabarber was also on the right track, but thrown by the texture. In fact the texture led to some interesting suggestions, including pumice, fossil, bezoar and Pompeian pinecone.

In the end, henstridgesj made the right connection and identified the species, with Anna Pike, rachel and Crispin Wiles all coming to the same conclusion. This is the dried and shrivelled remnant of a Gumboot (or Giant Western Fiery) Chiton Cryptochiton stelleri (Middendorff, 1847). Also known as the ‘Wandering Meatloaf’ for obvious reasons!

Chitons are an ancient class of mollusc called the Polyplacophora – a name that means “bearing many (or several) tablets (or plates)”. They get this name from the eight plates (also known as valves) that they have on their backs.

Most chitons have these valves visible (see below), but the huge Gumboot Chiton has the valves hidden underneath their rubbery girdle.

Tonicella lineata showing the eight valves characteristic of chitons

Chitons are remarkably conservative animals, having changed little since the group arose around half a billion years ago. They have few predators and manage to live a blameless and slow-paced life feeding on algae and detritus on rocks in the world’s oceans, that they rasp off with a fairly simple rasping radula.

There are few ways of spending time on the sea shore that are more enjoyable than turning over rocks in the quest for chitons. Except maybe finding washed-up bones. Or maybe finding both together!

Friday mystery object #199 answer

On Friday I gave you this rather beautiful object to identify,which came to light during our mollusc Bioblitz last week:

It turns out that it didn’t prove much of a challenge and was identified to species level in no time. So well done to Kevin, Anna Pike, @benharvey1 and Carlos Grau!

In fact, Carlos went a step further than identifying the specimen and told the very story I was planning to tell in this post. It’s great to hear stories like this about specimens or species, so I’ll share it with you in Carlos’ words:

This picture immediately brought back memories of my old seashell-collecting guide I had when I was about 12 and haven’t looked at for years and years (I will look for it next time I’m at my parent’s). The book said that this species was considered so valuable that fakes were made in rice paste by Chinese artisans, and that the counterfeits are now more rare and valuable than the actual shell! I remember finding that bit of information amazing.

It’s been so long I had to Google the book, it’s “Guide to Seashells of the World” by R. Tucker Abbott.

The animal is… Continue reading →

Friday mystery object #130 answer

On Friday I gave you this specimen to identify:

I thought that some of you might find it a bit tricky, since this is a shell from a group of animals that aren’t that familiar to most people.

Barbara Powell was the first to spot what this shell came from and her identification was supported by Dave Godfrey, Julie Doyle and henstridgesj. It’s a Continue reading →