GuidesMagazineShopBuy FossilsJoin Hunts
Doggerfan
I also don't have enough knowledge to make any more helpful suggestions, but I certainly do agree that the marks come from some kind of predator and that the creature died from the attack. Very interesting sample!
Best wishes from the Lake of Constance. Roger.
Quote 0 0
TqB
A suite of Hibolites jaculoides from a bedding plane in a fallen block of Speeton Clay, Hauterivian.
I'm reliably informed that they're from the base of bed C7H (thank you, Jack Doyle!).

The arrowed specimen has an interesting regular pattern of indentations and bumpy (regrown?) rostrum that I've not come across before.
IMG_0515_-_Copy.JPG 


There is a row of six equidistant indentations (one of which straddles the modern break at the 3cm mark):
IMG_0518_-_Copy.JPG 

IMG_0518_-_Copy_2.JPG 

IMG_0520_-_Copy.JPG 

Pattern of ridges on the opposite side:
IMG_0517_-_Copy.JPG 

Tarquin
Quote 0 0
valh
Hi Tarquin! Interesting Hibolites,I think its bitten someone...
Valerij
Quote 0 0
quagga
Looks like the mark of Suarez to me
Time is nature's way of stopping everything happening at once.
Quote 0 0
schming2001
As the guard was part of the insides of a belemnite, I would be surprised if the animal had survived such a severe bite to allow re-growth. I'm guessing that it was just distorted when bitten. What a super specimen! I love it!
Fossils are great.
Quote 0 0
deltapodus
quagga wrote:
Looks like the mark of Suarez to me


You have just raised a much needed laugh in the middle of report writing. 

On topic. Very interesting. I've done a lot of reading around predation on ammonites recently. Assessing the cause of damage can be  hard, and mainly consists of eliminating different possibilities, but two parallel, evenly spaced rows of marks rule against, for example, post-mortem transport damage: you'd expect such damage to be more random in its distribution. 
Those two rows are highly suggestive of bite damage, and would suggest a vertebrate predator. The lack of regrowth suggests the bite was fatal. Now you've got me trying to work out what the predator could have been.
  I'm still puzzled by the ridges on the underside. One thing I would also like to know: does it show any sign of acid etching? I guess a vertebrate predator would swallow a belemnite whole, so any sign of wear from digestive juices?
Finally found bone[biggrin]
Quote 0 0
quagga
The only vertebrates that I can think of that might have teeth fitting the bite pattern are sharks.  Some sharks are heterodont, some having different dentitions from the front to the back of the jaws and/or  top and bottom jaws, which might explain the ridges on one side.

Edited by quagga 2014-06-25 21:10:00
Time is nature's way of stopping everything happening at once.
Quote 0 0
deltapodus
I was contemplating ichthyosaur or plesiosaur, mainly because those parallel rows suggest with a straight, not curved tooth row. I had considered semionotid fishes like Lepidotes, but rejected them because their tooth rows seem to be curved. In all honesty, though, I  have no real idea.
Finally found bone[biggrin]
Quote 0 0
Elbert
Hello, assuming the teeth of the creature that ate the belemnite deployed a even pressure, one could conclude that the belemnite was taken in lengthwise...the pattern makes me think of a croc, something like a Steneosaur.
I know, this may be a long shot...Geek

 

greetings, Bert
the search is as valuable as the finds...
Quote 0 0
TqB
Thanks for the comments and suggestions, everyone! I'll look at shark/ichthyosaur/plesiosaur dentition more closely - the bite pattern is enigmatic even with the specimen in hand.
(Ed: and croc, thanks Elbert! Have crocs been found in the Speeton Clay?)

Deltapodus - I can't see signs of etching - under magnification, the surface has the same texture as others from the same horizon.

A bite just on the rostrum wouldn't necessarily be fatal - there were no vital organs there and plenty of severely damaged and regenerated rostra have been found. Predators would probably get a facefull of ink which might make them let go.

I think there might be a bit of overgrowth on this one although it probably didn't last long - it looks to me as if some of the damage is covered by scar deposits which might also explain the ridges.

Thanks for looking!




Edited by TqB 2014-06-26 09:53:39
Tarquin
Quote 0 0
Write a reply...


Discussions on fossils, fossil hunting, rocks, locations, and identifying your finds.
(C)opyright 2019 - UKGE Ltd and UK Fossils - Contact us