Jawless Creature Had the World's Sharpest Teeth 53
ananyo writes "An extinct primitive marine vertebrate had the sharpest dental structures ever known — with tips just one-twentieth of the width of a human hair, but able to apply pressures that could compete easily with those from human jaws. The razor-sharp teeth belonged to conodonts, jawless vertebrates that evolved some 500 million years ago in the Precambrian eon and went extinct during the Triassic period, around 200 million years ago. The creatures roamed the planet for longer than any other vertebrate so far–– and despite their lack of jaws, they were the first creatures to evolve teeth (abstract)."
How accurate? (Score:1)
Re:How accurate? (Score:5, Informative)
Not as much as you would think. Conodonts are composed of calcium phosphate -- the same stuff as our teeth. It's fairly durable mineral. They are usually extracted from rocks in almost unaltered state. Conodonts do get broken and worn like any other sediment particle, so sometimes they're a bit beaten up, but often they are nearly intact despite being fairly fragile-looking structures. Sometimes their surfaces even show wear from the time when the animal was alive (i.e. tooth wear). Growth lines and other structures are visible internally.
The rest of the animal -- the body -- is soft tissues, so that part rarely preserves and is flattened even when it is preserved, however, multiple specimens compressed in different orientations reveal the 3D structure. There are also slightly more robust structures around the eye sockets (sclerotic capsules).
Re: (Score:2)
Is there any compensation that has to be applied to fossils which are over 200 million years old?
No, I think their tooth patents are all expired...
Re: (Score:2)
Just a blast of Nitrous in the morning with your coffee...
Re: (Score:2)
Well there is a reason they were extinct. Teeth that sharp would 1. Either dull down quickly (depends on how long it lived) 2. Be fragile enough to break after catching prey.
Perhaps they were like rodent's teeth, constantly growing and softer on one side than the other, so that as it ate the tooth would sharpen itself and any breakages would be replaced.
Re: (Score:2)
Another dentist insight: dentists don't like to RTFA...
But super-sharp teeth can cause problems. “If you have sharp teeth they are more likely to break,” says Donoghue. To overcome this, the animals seem to have been able to re-sharpen and repair worn teeth throughout their lives — a quality that other vertebrates have failed to evolve.
Re: (Score:3)
I don't think you could call their design flawed: they roamed this planet for about 1/3 billion years.
From the summary:
Re: (Score:2)
Because you can tell from a fossil how long they were around. And you can tell that an animal looks like an eel by a set of fossilized teeth.
I don't care how great of a scientist you are, you can't predict what an animal looked like from a set of teeth. Imagine the wild designs they would come up with for humans if all they had to go on was a tooth.
Re: (Score:1)
No prediction here.
What are believed to be conodonts have been found in legerstatte deposit which can preserve impressions of softer tissues.
https://en.wikipedia.org/wiki/Lagerst%C3%A4tte [wikipedia.org]
Re: (Score:2)
Well there is a reason they were extinct. Teeth that sharp would 1. Either dull down quickly (depends on how long it lived) 2. Be fragile enough to break after catching prey.
Some species developed an ability to re-grow tooth material. Quoth TFA:
To overcome this, the animals seem to have been able to re-sharpen and repair worn teeth throughout their lives — a quality that other vertebrates have failed to evolve.
Re: (Score:1)
Because you don't even understand life itself! Life itself is completely unknown to one such as you.
Wow! There are dark rumors about you circulating all over the grapevine. They were started by... Komen Bryce himself!
The rumor's text? "Anonymous Coward is misign a few gigabit on his puter... bai2u... >_>"
I know, I know. Your very soul has been shattered. You are a mere shell of what you once were. You're nothing. You can just turn to dust and die now!
Here is the wikipedia article (Score:5, Informative)
of this eel-like creature [wikipedia.org]... looks like we don't know much about them aside from their teeth?
Meteorites suck. I mean blow.
Re: (Score:3)
There is no particular reason to think the Triassic-Jurassic extinction was caused by an impact event.
Re: (Score:2)
>There's little evidence to support it, just as there's little evidence to support any alternative theory
Exactly.
And I didn't say that OP was unreasonable.
Freaky Beasties (Score:5, Interesting)
Here [le.ac.uk] are some speculative drawings of the creatures. Getting caught in a swarm of thrashing sharp dental structures would make a good horror film.
Re: (Score:3)
"Heterochrony in cavusgnathid conodonts"
I love titles that I cannot begin to pronounce, much less understand.
Re: (Score:3)
Re: (Score:2)
Re: (Score:2)
Getting caught in a swarm of thrashing sharp dental structures would make a good horror film.
Yup, coming to a theater near you April 19 [imdb.com].
They still exist today (Score:2)
Re: (Score:2)
Having evolved to chew through solid rock... They bored into the earth, and have evolved to make sustainable life energy in the heat below the earth's mantle... What's that noise?... Come closer to the campfire.
If they are smart, they will evolve into goa'uld [wikipedia.org], and be preserved forever on Netflix [netflix.com]...
Just when you thought... (Score:5, Funny)
Just when you thought it was safe to go back in the water ... JAWLESS!
Hagfish (Score:3)
Re:Hagfish (Score:4, Interesting)
Everything is related, it is a question of how closely. Seems some taxonomies put them near the hagfish class and the lamprey class, however a 2010 paper argues they are not Vertebrata at all, or even Craniata.
Re: (Score:2)
Aren't hagfish (technically Agnatha) related? Yes, but probably not too closely? They are about as old. But the fossil information on early vertebrates and similar critters is very sparse. It's hard to tell all that much about them. For example, there is a phylum of critters called Chaetognaths whose fossils somewhat resemble both fish and conodonts. They have eyes, fins, teeth. But unlike the conodonts, they survived until the present allowing biologists to determine that internally, the chaetognats
Re: (Score:2)
Author doesn't understand pressure... (Score:1)
with tips just one-twentieth of the width of a human hair, but able to apply pressures that could compete easily with those from human jaws
The size of the surface area has no bearing on the amount of pressure that can be applied because pressure is force per unit area.
Re: (Score:1)
Re: (Score:1)
The size of the surface area has no bearing on the amount of pressure that can be applied because pressure is force per unit area.
Try again. Try harder.
Re: (Score:1)
Yep. The oil industry use them all the time.
Roger Ebert (Score:2)
Obvious (Score:1)
Given that it had no jawbone, it only makes sense that the teeth be sharp to still "get thru the point".