Dear Readers, I am an avid devotee of New Scientist magazine, in particular the short articles which present research from around the world, and which often reveal all sorts of wonders. So, this week I thought I’d share my two favourite articles.
The ‘Gian Paperclip’ Squid That Might Have Lived for Centuries
While Tyrannosaurus Rex was wandering the land 68 million years ago, a 1.5 metre long ammonite with a strangely twisted shell was patrolling the oceans, and individuals could have lived for up to 200 years. The ‘Giant Paperclip Squid’ (Diplomoceras maximum) had one of the most unusual shells of any ammonite (this group was one of the ancestors of the cephalopods that exist today), as you can see from the artist’s impression above.
The scientists who are studying the animal, Linda Ivany and Emily Artruc at Syracuse University, have been able to take the chemical signature of that strange shell and, comparing it with annual methane emissions that we know occurred in the oceans, they have come to the conclusion that, as with trees, each ‘ring’ in the shell represented a year. By counting the rings, it’s very likely that these animals lived for centuries. And as the shell grows by accretion, with each ring adding to the next, it might go some way to explaining the ‘paper-clip’ look of the animal.
This long life is very unusual because cephalopods are normally very short-lived creatures – many octopuses only live for a year and the longest-lived member of the family, the nautilus, lives for a maximum of twenty years. The scientists speculate that because the paperclip squid lived in Antarctica, it may have had a very slow metabolism and breeding rate to cope with the difficult conditions.
The name ammonite means ‘Horn of Ammon’, the ram-like god of the Ancient Egyptians, and you might recognise the more typical shell below. Sadly, all the ammonites were wiped out in the same incident that destroyed the dinosaurs, and there are several theories about why these oceanic animals became extinct when other ocean-goers didn’t. One theory is that ammonites lived on plankton (their beaks are very different from present-day cephalopods, which eat much bigger prey), and we know that there was a long period when plankton populations crashed, so it’s possible that only more omnivorous families of animals survived.
A second theory is that the young of ammonites floated closer to the surface of the oceans, and their shells were destroyed by the acidity of the water following the meteor impact which wiped out the land animals. Creatures who lived deeper in the ocean, scientists believe, were more likely to survive.
Whichever was the case, it seems a shame that this group, so common in the fossil record and so successful for over 300 million years, was wiped out in the geological equivalent of the blink of an eye.
And for our second glimpse into the natural world this week, this headline has attracted attention beyond the ranks of arachnophiles:
‘Some Male Spiders Tie Up Females Before Mating to Avoid Being Eaten‘
As you might expect, this tale of spider bondage has got many news outlets over-excited, and, as with most spider stories, they choose to illustrate them with photos of completely the wrong species. So, here are the facts! No fake news here people (though please note that I’m always open to being told that I’m wrong about something – many of you are experts in your fields, and I’m delighted to learn).
The Running Crab Spider (Thanatus fabricii) lives in the Negev Desert in Israel and, as with many spiders, mating can be a fraught occasion. Lenka Sentenská at the University of Toronto Scarborough, Canada, had been observing some extremely fast movements made by the males of this species when they encountered a female, but, by slowing down film of the action, she was able to see exactly what was going on.
When a male encountered a female, he would rush in and bite her legs, leaving her so astonished that she would sometimes play dead. While prone, the male would bind her legs, mate with her and run away.
However, as usual, things were not quite as they seemed. The females would sometimes kill and eat a male who wasn’t fast enough, and the scientist notes that it doesn’t take much effort at all for the female to break free. Sentenská speculates that the silk used to tie the female up may contain a chemical signal from the male, and if she approves of him she is more likely to allow him to mate.
“It appears brutal, that the female has no choice, but that’s probably not how it is,” she says. So, a little less ‘Fifty Shades of Grey’ than some newspapers seem to think.