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Identification

2 Posts tagged with the specimen tag
1

You only have to browse through the Fossils and rocks forum to see how many of the suspected fossils put on there turn out to be something completely different! Fossil eggs, bones, turtles, ferns, footprints, you name it, natural rock and mineral processes can mimic it. We call these natural rock and mineral specimens that resemble or are mistaken for fossils "pseudofossils". This post doesn't seek to go through the most common look-a-likes, but if you google "pseudofossil" you will find many excellent guides out there.

 

This post is just some of my personal favourites from the last year. Fun and amazingly co-incidental pseudofossils are one of my favourite parts of my job in Earth Sciences identification.

 

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"Fossil bird head"

 

It's got everything - neck, beak, even an eye. But this shape is created by the growth of a mineral upon the rock surface.

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"Fossil shark"

 

This shark shape, silhouetted in white against the dark background, would have me swimming for my life if I saw the silhouette peaking out of the sea. But it is just a chance area of cleaner white Chalk against a backdrop of Chalk discoloured by dirt and moss.

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"Fossil fish"

 

I can see what they mean, it looks like a guppy with a long flowing tail and fin. But this is a type of the rock flint known as banded flint. Banded flints form a series of roughly parallel lines such as this, which can create all sorts of misleading shapes. The cause is still not fully understood but the movement of water and silica through the flint is thought to be involved.

 

The rock flint can mimic any kind of fossil you can think of - bones, eggs, whole heads and bodies, you name it. Look out for a blog all about the wonders of flint coming soon!

 

2011-0058 dinosaur head pseudofossil 001.jpg"Fossil dinosaur head"

 

If this were a dinosaur, I can even see what kind it would be - one of the duck-billed hadrosaurs I reckon. Sadly, this is just the shape of the lump of rock, that had probably been exaggerated by weathering.

 

 

While writing this I've realised that these pseudofossils do have something in common after all. They all demonstrates one of the key things to appreciate when looking for fossils: don't look for the overall shape of an animal. This is because the soft parts of animals like muscle and skin only fossilise very rarely and in unusual conditions. You can assume you won't come across soft part preservation without knowing what to look for and where to look. To find fossils, look for the hard parts such as bones and shells, and bear in mind these are most often broken, mixed up and/or isolated.

 

Although we can say what these aren't, the hardest question to answer is, so why did the rock or mineral form or weather into exactly that shape? There are millions of rocks out there and so even if such coincidental resemblences are rare, there will still be plenty of pseudofossils. And of course those are the rocks that are going to catch your eye and get picked up.

 

So what should you look for? This page on our website has some good information and links for fossil hunting advice. And of course we will be happy to see whatever you find, whether rock, mineral or uncannily-vegetable-shaped-rock on the rock and Fossil forum here.

 

Happy fossil - and pseudofossil - hunting!

0

Phew, what a week it has been, what with the media launch and then International Year of Biodiversity Day on Saturday 22nd May, it feels like we haven’t left the museum in a week!

 

As part of our launch the Museum commissioned a MORI survey into just how much British citizens know about our native species.

Well, the results were not surprising. Here is what the headlines sa.:


Less than a quarter (24%) of UK adults are able to correctly identify the common UK sycamore tree, according to a survey on behalf of the Natural History Museum, which launches the Angela Marmont Centre for UK Biodiversity today.

 

So we have some work to do in getting people interested in natural history – this is good – this is what we are here for! We all have a responsibility as part of society to respect and conserve our natural environments and all living creatures that this supports.

 

This is just what SH did in preparation for IYB day on Saturday. Armed with nothing more than a sweep net, a jam jar, and some insect repellent our intrepid entomologist headed off to the New Forest to see what he could find. He arrived on Saturday with all manner of beasts to show and tell as we opened our doors to celebrate International Year of biodiversity.

 

Anyone that came to IYB day would have met the irascible pair of very friendly Cockchafers (Melonontha melonontha) (who were determined to fly away) along with their cousins, the beautiful metallic green rose chafers (Cetonia aurata), one of the Clerid beetles, (Pyrochroa coccinea) which is bright red (the clue is in the name!), and a rogue spider, safely held in a sealed plastic cup, the woodlouse spider, (Dysdera crocata), which as the name suggests, eats woodlice, but is also partial to humans!

 

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We had hundreds of people through the doors and there was lots to talk about, see and do. We were there, the Identification and Advisory service - of course - though we only received one butterfly for identification but did manage to tell anyone who stood still for long enough all about insects, spiders, bugs, whatever.

 

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Our earth sciences experts were on hand to show off some of our British fossil collections, along with some extant relatives, and did some explaining about how we know what the soft body parts of say, the ammonite was like - we got some complicated questions!

 

Our resident botanist proudly showed off a British herbarium specimen of the Ghost orchid  - see its heroic story here.


 

The OPAL team were also there and got lots of attention as they had very studiously been out pond dipping at the crack of dawn in our nature garden. We have a very healthy pond apparently, with good environmental indicators such as caddis fly larvae (who disguise themselves in a 'case' they make from bits of pond debris), tadpoles, leeches (eurgh!) flat worms, mayfly larvae, and it goes on...

 

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Go to the OPAL website to join and take part (you get a free pencil!)

 

One person that realy stood out (nice shirt!) was the UK naturalist Chris Packham who came in for a chat, which was nice!

 

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