[Non-Ceph] Bits 'n Pieces

[Architeuthoceras]

Falcarius utahensis Missing Link or just strange?

 

[Phil]

Hi Monty,

Funny, I always thought that fish evolved in the ocean, and not on continents at all...

Good point!

Very interesting find, though. I've read that the rise of the teleost fishes is believed to have been a major factor in the dethroning of the ammonites, ...

Well....hesitant...the earliest teleosts appeared in the mid Triassic, at some point around 235 mya, this was also roughly the point when the first true ammonites started to appear. I don't therefore think the actual rise of the teleosts affected the ammonites, as they both evolved to become very successful groups concurrently. Although the size of the ammonite group varied wildly through time it reached a peak in the mid-Cretaceous, so it is perhaps possible that maybe teleost (and reptile) predation began to affect their numbers as the group went into a slow decline from that point on.

In short, I really don't know, we really need a fossil fish expert here to explain fish diversity in ancient seas.

...but I have a friend (who is very smart, but also sometimes prone to overstate goofy theories) who notes that ammonites seem to have been "drilled" a lot, so he thinks that it was faster, shell-less cephalopods & their radulas that were the most effective ammonite predators.

It would be very interesting if your friend has any evidence that other cephalopods preyed on ammonites, it'd be great if he would be willing to provide some references as I could find nothing on the net about this. I thought that most drill marks on ammonite shells were mostly thought to have originated from gastropods and limpets, probably mostly after the death of the animal. Certainly there is evidence that short necked plesiosaurs and mosasaurs preyed on ammonites, but, again, I have been unable to find references to teleost fish stomach contents containing ammonoids. Maybe your friend has access to a scientific library?

This idea seems to be possibly backed up by this article, since it implies that this early fish was more scavenger-like than agressive predator (but it's always dubious to make sweeping conclusions from a small sample size-- fish may have been as diverse then as they are now!)

- M

Yep, totally agree. I think these earliest fish were supposed to be something akin to the modern hagfish. Anyone remember seeing them feeding off the whale carcass on 'The Blue Planet'?

 

[Phil]

Prehistoric Chinese Dinosaur-Eating Giant Badger

No, it's not April 1st. This is real!

 

[monty]

Prehistoric Chinese Dinosaur-Eating Giant Badger[/url]

No, it's not April 1st. This is real!

This certainly counters everything I've ever heard about early mammals (it's amazing how much of the stuff taught as "known" to high school students turns out to be "a guess that was wrong.")

However, my first thought was "Perhaps if we build a large, wooden badger..."

- M

 

[monty]

Well....hesitant...the earliest teleosts appeared in the mid Triassic, at some point around 235 mya, this was also roughly the point when the first true ammonites started to appear. I don't therefore think the actual rise of the teleosts affected the ammonites, as they both evolved to become very successful groups concurrently. Although the size of the ammonite group varied wildly through time it reached a peak in the mid-Cretaceous, so it is perhaps possible that maybe teleost (and reptile) predation began to affect their numbers as the group went into a slow decline from that point on.

Hmm. It sounds like my source about this may have not been so good-- it was some years ago, but I think it was a "popular science" book of some sort that I though was credible. I thought it was going into details on the "shelled cephalopods were the dominant free-swimming animals in the sea for a long time, but they started to decline and were mostly driven into the deep sea when the teleost fishes arose and out-competed them" theme. I thought it mentioned ammonites in particular in this context, but if the teleosts and ammonites arose simultaneously, perhaps they were referring more to earlier shelled cephs, and I'm remembering wrong.

In Ward's Natural History of the Nautilus he refers the notion that increasing number of shell-crushing predators evolved in the Mesozoic, and that (presumably as a result) ammonite shell scultpture and ornament coarsened in the Mesozoic compared to the Paleozoic and "certainly did so during the Cretaceous Period" (is he uncertain about the Mesozoic?) He goes on to speculate that ammonites may have been forced to deeper water by "competitive or predatory pressure," but doesn't mention what specific predators he thinks were the cause.

I wish I could remember the source for the teleost fish competition hypothesis-- it was when I was trying to learn a lot about cephs in general, so I was reading a bunch. My recollection is that there was one book that had a chapter on biological reasons for the ammonites and nautiloids having lost their place as the primary form of free-swimming animal. I had the impression this was "stuff all the real palaentologists know," so I didn't really note it as a reference, more as stuff I should know if I was to be able to read more specific papers. What I remember is that there was discussion about vertebrates developing hemoglobin for better oxygen transport in blood, mylenated axons for faster and more compact nervous systems, and better kidneys (and maybe other excretory issues). It went on to hypothesize that the coleoids lost their shells in order to become fast enough to compete, because the shells were no longer adequate protection, and they added so much drag that the fast fishes would swim circles around them. I was impressed by the fact that the successes of vertebrate fish could be thought of as driven by the need to compete with the established cephalopods, so in some sense a lot of vertebrate development was driven by the pressure to compete with the established cephalopods...

I feel foolish for not noting a reference on this, though, since it sounds like it would be interesting to re-read, pass on to tonmo folks, and track down some of the references... (we need a "kicking myself" smilie!)

It would be very interesting if your friend has any evidence that other cephalopods preyed on ammonites, it'd be great if he would be willing to provide some references as I could find nothing on the net about this. I thought that most drill marks on ammonite shells were mostly thought to have originated from gastropods and limpets, probably mostly after the death of the animal. Certainly there is evidence that short necked plesiosaurs and mosasaurs preyed on ammonites, but, again, I have been unable to find references to teleost fish stomach contents containing ammonoids. Maybe your friend has access to a scientific library?

Well, he certainly had access to a scientific library when he came up with this idea, but he's also done some field work (he was a geology grad student at the time). I'm not sure I have his email address, but I'll see if I can ask him if he has references, or if he just observed this in some fossils. I believe he wasn't doing field work on cephs per se, and may have observed things he couldn't publish (he mentioned he had found some interesting fossils in a foreign country where politics prevented him from collecting, documenting, or doing other useful things with them without some sort of government permits and regulation that he didn't qualify for.)

- M

 

[Phil]

Thanks for the above Monty, very interesting reading indeed. Maybe it was predation pressure that drove the nautiloids into deeper water in Cretaceous? Nice idea.

I digress.....

And now the dreaded Fossil Joke:


Did you hear about the professor who took the first timers out on a fossil hunt?

Yeah it seems that one of the first timers found a beautiful mosasaur jaw fragment with several teeth still in it right next to the professor's foot! The professor became a little upset that this novice had found such a wonderful prize within "his space" and proceeded to try and talk the finder into letting him add it to the University (his) collection. The student repeatedly told him "NO!"

Finally the professor in one last attempt asked, "Why not?" The student then very calmly replied...

"It's my first fossil. I can't give it up. It has too much sedimental value!"

 

[tonmo]

Come on, Phil. How is that joke funny?

Don't ask me, folks. Jurassicking the wrong person.

 

[cthulhu77]

Oh Tony, don't be sooooo cretaceous !!!!

 

[oscar]

wow, no bones or teeth? i would love to see that thing swimming! or as a fossil...
...
...
... err

Oh and by the way i love all the fossil jokes guys! very cool

 

[spartacus]

Coprolite happens eh ?!

Keef

 

[Phil]

Thankfully Paleo Jokes are few and far between. Here's two more I stumbled upon, laughs not guaranteed!

Predictable Museum Joke

Some tourists in the Chicago Museum of Natural History are marveling at
the dinosaur bones. One of them asks the guard, "Can you tell me how old
the dinosaur bones are?"

The guard replies, "They are 73 million, four years, and six months old."

"That's an awfully exact number," says the tourist. "How do you know
their age so precisely?"

The guard answers, "Well, the dinosaur bones were seventy three million
years old when I started working here, and that was four and a half years
ago!


Utterly Bizarre Cladistics Joke

A cladist's wife is pregnant. One day she is experiencing labor pains.
The cladist calls an ambulance. His wife and him arrive safely at the
hospital. After a few hours of pacing back and forth in the waiting room,
the doctor congratulates the cladist: "Congratulations, you have two new
daughters." The cladist asks the doctor in excitement: "Doctor, does that
mean that I have twin daughters?" The doctor answers, "No, there was no
symmetrical split. Instead, there was an asymmetrical split. That means
one of your daughters is 25 years older than the other one, but your wife
seems to be missing."

 

[pocketmoon]

"it's amazing how much of the stuff taught as "known" to high school students turns out to be "a guess that was wrong."

The first lesson ever taught at school should be :

"For the rest of your academic life, everything you will be taught will only ever be opinion."

I'd love to have a brief work with the scientist who termed the phrase 'Junk DNA'...

 

[monty]

"it's amazing how much of the stuff taught as "known" to high school students turns out to be "a guess that was wrong."

The first lesson ever taught at school should be :

"For the rest of your academic life, everything you will be taught will only ever be opinion."

I'd love to have a brief work with the scientist who termed the phrase 'Junk DNA'...

Hear, hear!

Quite possibly, the only human ever to only use 10% of his/her brain was the person who said "humans only use 10% of their brains."

- M

 

[spartacus]

If Kevin only uses 10% of his brain what genius must he be capable of when the remainder kicks in ??

Keef

 

[Clem]

Alright.

Who's the wise guy who gave this thread one star?