Monthly Archives: April 2014

An elk that wasn’t an elk

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A herd of the giant Megaloceros giganteus. Standing proud: A herd of the giant deer Megaloceros giganteus during the closing years of the Pleistocene. (Painting by Tabitha Paterson)

To see an Irish Elk (Megaloceros giganteus) in all its glory, visit the National Museum of Ireland, in Dublin. Here, skeletons of this magnificent beast are articulated, proudly towering higher than the visitors. What really stands out are the incredibly enormous antlers, spanning 3.6 metres across! Standing face to face with a skeleton of Megaloceros you can imagine the awe-inspiring beast, roaming in herds across Europe around 13,000 years ago, at the very twilight of the Pleistocene.

Known as ‘the Irish Elk’, Megaloceros was neither exclusively Irish, nor an elk. This giant was the largest deer to have ever existed; it’s closest relative, the Fallow Deer (Dama dama), was half the size! There were elks in Ireland, many of which are found in ancient bogs around 13,000 years…

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The forgotten sabertooth

TwilightBeasts

Homotherium latidens. A powerful, confident and rather thoughtful European Scimitar Cat (Homotherium latidens) roaming the Middle Pleistocene. (Painting by Tabitha Paterson)

If the Pleistocene megafauna held a popularity contest then I’m certain that some species would pop up more than others. The woolly mammoth (Mammuthus primigenius), the giant ground sloth (Megatherium americanum) and sabretooth cat (Smilodon fatalis) are probably the gold, silver, and bronze of extinct mammals. Diego from the Ice Age films, the striped menace in 10,000BC, and (perhaps showing my age) the sabretooth in Sinbad and the Eye of the Tiger are all clearly typical of Smilodon sp. The long thin canines protrude well below the lower jaw, and the robust bear like bodyform that this genus is known for are obvious in all three cinematic depictions.

The reason that Smilodon fatalis has embedded deep into the collective unconscious can be put down…

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The croc in the rock

Number 16 of this series of bad casts is another shocker. All the casts are actually really bad (possibly apart from that pretty darn good bad cast, but this is a cast of a model, not a real fossil). It is amazing how truly bad these casts are and nobody seems to have ever questioned them!

This week’s specimen fails to excite, as you would expect by now.

Another terrible bad cast. A head of a crocodile and a few vertebra. Remember, these bad casts actually belong in a museum. Why?!

Another terrible bad cast. Remember, these casts actually are in a museum collection.

 

The ‘rock’ for this cast is fairly good for a change. Normally, the ‘rock’ (the block the fossil sits on) is just splattered with one colour where you can see the enormously clumsy brush strokes. This one has a little shading, and even a couple of ‘cracks’ thrown in. Nice touch.

The ‘rock’ looks pretty real. This (momentarily) takes your eyes away from what you are supposed to be looking at; the tennis racket in the middle of the slab.

The tennis racket is, of course, the cast of the fossil crocodile head. There are a few other bones included; two vertebrae and a leg bone. Presumably these were on the original fossil.

‘Presumably’, ‘probably’, ‘may have’, are words that often come up in this series of posts, because there is very little information with the specimens. With this cast there is a faded number but no information.

We can make educated guesses about what it is and why the museum possibly has it.

Looking at the snout, I know it is a crocodile skull. Alligators have wider snouts, whereas crocodiles have long thin snouts. It is quite a small specimen, but why have one?

I have a tingly feeling that all of these bad casts may have once been used to illustrate life through time. The collection of casts includes some trilobites, some ancient fish and even a dinosaur tooth. There are some mammals as well (which will come in the next few weeks). This crocodile ‘fossil’ may well have been used to show the people of Plymouth in 1910 a selection of different creatures that lived millions of years ago. Although the fossil is pretty bad, the choice of animal pretty good.

True crocodiles evolved around 200 million years ago. Before these, the ancestors lived on land and looked a little different. In the skull you can see four holes;

Another terrible bad cast. A head of a crocodile and a few vertebra. Remember, these bad casts actually belong in a museum. Why?!

The crocodile skull has four holes on it’s head.

The front two holes are for the eye sockets. The two holes at the back are shared with many other animals, including, birds, snakes, lizards, dinosaurs, rhynchosaurs and others. These two holes (found in diapsids) would have attached muscles to the head. Because they are present in all these animals (including some other extinct ones), it shows that they are all closely related. But crocodiles and birds are even more closely related.

Crocodiles, dinosaurs and birds all belong to the group called archosaurs. This group is defined by the animals within it having two extra openings in the front of the skull (below the eye sockets). Sharing a similar feature like this means that the animals in this group all shared a common ancestor which split apart and evolved into some incredible forms!

Around 250 million years ago, during the Triassic Period, the dinosaurs were becoming the dominant land animals. The ancestors of crocodiles (known as crocodylomorphs) had evolved to take advantage of a number of food sources, including insects, meat, plants and fish. These land loving ancestors felt the pressure of the successful dinosaurs, and around 50 million years later, during the Jurassic Period, crocodiles were living solely in the water.

It was at this time, around 200 million years ago, that crocodiles began to look like crocodiles. Before then they were strange reptiles, some with nostrils on the tops of their heads (rather than at the end of their snouts), and others walks on two legs. They waited patiently in the rivers while large dinosaurs were taking sips of water, and some grew to enormous sizes to tackle this larger prey. The enormous Sarcosuchus was almost as long as a basketball court (around 20m), and would have enjoyed a dinosaur for dinner.

There is more information behind a bad cast than would first appear. A lot of information can be told around this bad cast and we can work out why the museum purchased it.

I may be trying to make this bad cast look extremely good with all the exciting information. Our educated guesses may actually be nothing more than an old Christmas present to a previous curator who left it in the office by mistake. I will never know.

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A bad cast of a truly bad fossil

Fossils can tell us so much about the history of life on Earth. They can help us identify where the beginnings of great groups of animals began; tell us about wonderful animals and plants that once lived; and reconstruct environments long vanished. They are the all that remains of a once living thing. That is pretty amazing to think about; a long, long time ago, this was actually a breathing, moving, eating real thing.

Fossils are pretty rare. To become a fossil the organism (that is, the living thing) has to drop dead in just the right environment, preferably one which covers it really quickly with sediment so scavengers won’t rip apart the body. Fine sediment is best to preserve the finer detail, as coarse sand grains can gently and slowly rub against soft parts. Then it has to be buried deep under more sediment and not disturbed. Slowly water is squeezed out of the sediment under the enormous weight of more sediment above. (Imagine a wet t-shirt, fold it in half, and lay it on a table. Put a book on top. And then another, and another, eventually the weight of the books will squeeze all the water out.) As water is squeezed and pushed it moves through the sediment, and if there happens to be the remains of a long dead organism, minerals in the water are deposited creating an exact replica of the dead organism; the fossil. Sometimes the minerals can replace even the smallest details of an animal, literally turning it to stone. More often than not all we are left with is the hard parts, some bones, shells and teeth. That is, if we are lucky to find them.

Unfortunately not all museums lie on top of an ancient graveyard of extinct creatures. To compensate, they may buy specimens that represent the main group (which are usually pretty low quality). Or they buy casts.

For something so incredible as discovering the evidence for a long lost animal millions of years ago, it is such a shame early casts of these remains were so bad. Sometimes, however, the fossils themselves may be truly bad.

This weeks bad cast is bad, but the real fossil isn’t much better.

Yep. This is a real cast of a real fossil. Nope. I have no idea why museum curators 108 years ago spend money on this. No idea at all.

Yep. This is a real cast of a real fossil. Nope. I have no idea why museum curators 108 years ago spend money on this. No idea at all.

 

Here is the ‘top’ (or maybe the side?) which shows a little more detail. Just a little.

 

The 'top' or the 'side' of thE fossil. I'm not quite sure. But I do want to eat it.

The ‘top’ or the ‘side’ of the fossil. I’m not quite sure. But I do want to eat it.

 

You may be surprised to know it is actually a real cast of a fossil fish tooth. This fossil fish, a shark known as Psammodus rugosus, lived during the Carboniferous Period (around 350 million years ago). The cast does actually portray the really fossil fairly well, as you can see here.

Actually researching information for this shell crunching shark didn’t turn up much at all. I guess the internet doesn’t have much to say about a rather dull looking, flat shark tooth. It does get a hit on Google books, from a book written in 1843. Exciting, and no doubt a riveting read.

The fossil does crop up on the wonderful Grant Museum’s ‘Underwhelming Fossil Fish of the month’ blog (here). It appears there is not much to say about this ancient creature by the Grant Museum either.

Which begs the question of why, oh sweet lord why, would someone authorise money being spend on something that looks like a delicious chunk of honeycomb toffee? (Of all the chocolate bars, those with honeycomb centres are my weakness. And ones with coconut. And fudge. And Toblerone. I really like Toblerone with honeycomb bits.)

Although this fossil cast (and perhaps the real fossil too) doesn’t get you excited, it is all that remains of a shark that actually swam around over 350 million years ago. It may be a bad cast, but this represents something that once lived.

 

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The king lizard whale

This weeks bad cast doesn’t really look like a fossil, yet it may be from a creature you might recognise.

 

A very very poor quality cast. Those pesky fossil cast dealers.

A very very poor quality cast. Those pesky fossil cast dealers. Doesn’t look like much, does it?

 

I nearly took the photo this way by mistake;

 

Has someone made a cast of a banana?

Has someone made a cast of a banana?

 

Even worse, I almost took the photo this way;

 

Well. Good job I didnt take the photo this way.

Well. Good job I didnt take the photo this way. Otherwise, this could have been mistaken for a cast of something unimaginable. 

Shocking. Not the shape of the fossil (which is a little), but the quality. How can this be sold as a cast of a ‘real’ fossil? It has. Frustratingly it was 108 years ago, so the dealers cannot be challenged by trading standards. There is no time travelling ombudsman. (Now there’s a cool job.)

This is actually a cast of a fossil tooth! The tooth does exist somewhere, but you wouldn’t be surprised to know that there is no information with this specimen about the original fossil. That would be giving us too much!

The label names the tooth as belonging to Zeuglodon cetoides. This extinct beast is actually one you may recognise; Basilosaurus cetoides. It’s an amazing creature, with an interesting history.

In the earl-1800s, huge fossil bones had been discovered in the sediment of the American South. Huge, and fairly common, these had been used as furniture! A couple of bones were sent to the American Philosophical Society for identification. (The American Philosophical Society was set up in 1743 by Benjamin Franklin and John Bartram and early members included three presidents of the United States of America).

The anatomist who looked at the bones (mainly the bones from the spine; the vertebra), Richard Harlan, compared them to the (then) recently discovered dinosaur bones of Megalosaurus and Iguanodon. Harlan thought they looked very similar, but bigger. So he named the creature ‘Basilosaurus‘ meaning ‘king lizard’.

Was this another type of giant extinct lizard? Another new dinosaur discovered? Nope.

Harlan visited England and took some of his newly described Basilosaurus specimens with him to show to the great Richard Owen. (Richard Owen was an incredible British  comparative anatomist who was able to identify an extinct animal by one bone. He was brilliant, but he was also very arrogant, egotistical and deceitful.) Owen looked at the fossils and there were traits that looked like a mammal, and lots of similarities to whales. He renamed the giant ‘Zeuglodon‘ and the American anatomist agreed.

However, there are rules when we name animals and plants (and bacteria). Them rules are there for a reason. The rules of taxonomy are there to make sure that an organism doesn’t have five different scientific names. It also gives priority to the first name given. So in the case of this big whale, it was scientifically described as Basilosaurus before it was called Zeuglodon, so Basilosaurus takes precedent.

This tooth belonged to this whale that lived during the Eocene (around 40 million years ago). About as long as 4 double decker buses, it was a heft animal! As you can’t really see, the teeth were quite chunky and pointy; the shape, and that one fossil had a stomach full of fish indicate that they fed on fish in the oceans. Closely related to modern whales, the Basilosaurus were not their ancestors; this group and the group of modern whales shared a common ancestor that lived around 50 million years ago.

A delightful little sketch of two Basilosaurus. Big, long, whales. Lovely. (Image from here)

A delightful little sketch of two Basilosaurus. Big, long, whales. Lovely. (Image from here)

Beneath this shockingly bad cast is the tale of an whale that once swam in the oceans millions of years ago. Fossils, and potentially casts of fossils, reveal such awesome clues to forgotten worlds. Many of the bad casts in this series do not give the original fossil any thing to get excited about. This bad cast is no exception.

 

 

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