Ammonite meal?

[Ruger9a]

Good evening folks.  I have an ammonite that I've had for many years and until today I didn't mess with it.  I semi prepped it an in the process I noticed (what appears to be) a "bite" mark on the outer shell.  Can anyone confirm this for me?

 

[Ruger9a]

Here are the rest of the photos.  I almost forgot, I left a piece of ??? that was attached to it.

[grandpa]

An interesting (and somewhat controversial) subject indeed. 

For images see:

https://images.search.yahoo.com/search/images;_ylt=AwrJ6yhzY81fDJ0A2qJXNyoA;_ylu=Y29sbwNiZjEEcG9zAzEEdnRpZAMEc2VjA3BpdnM-?p=ammonite+bite+marks&fr2=piv-web&fr=yfp-t#id=67&iurl=https%3A%2F%2Fwww.bigfossil.com%2Fekmps%2Fshops%2Fvarahfossils%2Fimages%2Fasteroceras-showing-bite-mark-lower-lias-lyme-regis-[5]-3386-p.jpg&action=close

 

Notice there are two "types" of bite marks featured in the images: (1) One group has been attacked in the ventral region and looks like your example above and is often found in Lyme Regis.  It is attributed by some to be an attack by other cephalopods (e.g., squid) and by others to be large fish or mosasaur attack. (2) The other group looks like rounded "teeth bite impressions" and it is debated whether this is limpets or mosasaur attacks.

 

References for each type:

1)  https://www.lymeregismuseum.co.uk/related-article/fatally-bitten-ammonites/

     https://phys.org/news/2010-12-ammonites-eaten-fellow-cephalopods.html

     https://www.researchgate.net/publication/229134933_Ventral_bite_marks_in_Mesozoic_ammonoids

 

2) file:///C:/Users/Tom/AppData/Local/Temp/BITE_MARKS_ON_AN_AMMONITE_RE_EVALUATION_OF_THE_LIM.pdf

    https://blogs.scientificamerican.com/laelaps/the-mark-of-the-mosasaur/

    file:///C:/Users/Tom/AppData/Local/Temp/Kaseetal1998.pdf

 

Conclusion:  Looking at your picts compared to those of the type 1 predation, I would say that yours is a good match with the examples pictured in the articles.  I think your ammo was indeed a victim of an attack.  An attack by what is, it would seem, open to debate.

 

 

[Top Trilo]

Who would want to eat an ammonite? Sounds like a lot of work and crunchy shell to get a little bit of food.

[Thomas.Dodson]

2 hours ago, Top Trilo said:

Who would want to eat an ammonite? Sounds like a lot of work and crunchy shell to get a little bit of food.

It seems like that but there are indirect and direct links between lots of predators eating ammonites including crocodiles, icthyosaurs, plesiosaurs, sharks such as hybodonts, and other cephalopods. It's actually pretty common to find possible predation damage on ammonites, especially on that ventral area Grandpa mentioned.

[FranzBernhard]

6 hours ago, Top Trilo said:

Who would want to eat an ammonite? Sounds like a lot of work and crunchy shell to get a little bit of food.

Yeah, its a crunchy meal, but these ammo shells are not super-stable. Some ammos tried hard to make it more stable or less appealing for predators. There are many kind of shell crunchers still living. Its a matter of seconds.

 

4 hours ago, Thomas.Dodson said:

predation damage on ammonites, especially on that ventral area Grandpa mentioned.

This may have something to do with the lifestyle of the ammos?

 

6 hours ago, Top Trilo said:

lot of work

I am very impressed by the feeding habit of naticid gastropods. They are patiently etching and drilling cirular holes in the shells of their pray. And most often, they are successfull!
Franz Bernhard

[dhiggi]

10 hours ago, Top Trilo said:

Who would want to eat an ammonite? 

Globidens?

Presumably an abundance of predators was the reason that some ammonites developed spikes

[RuMert]

The shells were probably thin enough to provide buoyancy, hardened by curvy chamber walls - but the bite was targeted at the living chamber with no walls. Ventral bite severed several key muscles and the ammo body fell out of the shell

[Ludwigia]

3 hours ago, RuMert said:

The shells were probably thin enough to provide buoyancy, hardened by curvy chamber walls - but the bite was targeted at the living chamber with no walls. Ventral bite severed several key muscles and the ammo body fell out of the shell

Or was pulled out by the predator. This is a scenario which could support the thesis of a bite. Or a large crab claw could have done the damage.

[Ruger9a]

Thank YOU all !!!!!!  Can anyone tell me the name of the ammonite I have?

[Ludwigia]

1 hour ago, Ruger9a said:

Thank YOU all !!!!!!  Can anyone tell me the name of the ammonite I have?

It looks like a Perisphinctes from Madagascar to me. Why did you type China in the tags?

[Ruger9a]

Just now, Ludwigia said:

It looks like a Perisphinctes from Madagascar to me. Why did you type China in the tags?

Sorry, that's where I purchased it from.  Thanks for the identification.

[FranzBernhard]

10 hours ago, Ludwigia said:

Perisphinctes from Madagascar

Nothing has been done to this specimen, no aperture cut off, no polishing! That´s quite unusual for this source, maybe its an old specimen (well, collected and exported some time ago )? Nice!!
Franz Bernhard

[Ludwigia]

4 hours ago, FranzBernhard said:

Nothing has been done to this specimen, no aperture cut off, no polishing! That´s quite unusual for this source, maybe its an old specimen (well, collected and exported some time ago )? Nice!!
Franz Bernhard

Yes, I was wondering that myself, which is why I said it just looks like one.

[Ruger9a]

7 hours ago, FranzBernhard said:

Nothing has been done to this specimen, no aperture cut off, no polishing! That´s quite unusual for this source, maybe its an old specimen (well, collected and exported some time ago )? Nice!!
Franz Bernhard

 

2 hours ago, Ludwigia said:

Yes, I was wondering that myself, which is why I said it just looks like one.

Good morning guys.  Yes, I purchased this fossil back in the 07/08 ish timeframe.  Don't know if that will make a difference but I figured I'd let you know.

[Ludwigia]

It is even still possible now to get old raw material from Morocco. Like I said, it looks like one to me, but there are other sites around the world which produce similarly preserved Perisphinctes, so we'll never really know for sure. Just put a question mark beside it.

[Ruger9a]

Ludwigia,  Thanks for the info.  I purchased it from a guy in China, that purchased (supposedly on site) a large group of them from a dealer in Morocco.  He didn't know anything about them except that they were fossils.  I have two different types that I purchased from him and will post a few of the for you enjoyment......... 

[Ludwigia]

Ok then. There you are. It's from Morocco.

[Ruger9a]

Here are a few of them.  The first one I would need an identification for.

[Ruger9a]

The rest.

[Ruger9a]

The rest..................

[Norki]

Just for reference, here is a placenticeras ammonite that shows evidence of predation by mosasaur. I know the jury's still out on whether these holes are caused by mosasaur bites or limpet boreholes, but the similarity between the "V" shape pattern on either side of the shell seems to me like pretty compelling evidence for predation.

Notice how in this case that the body chamber is completely shattered and missing, except for the edges which show apparent evidence of a traumatic break. I think that the leading theory, at least with these placenticeras examples, is that the mosasaurs would attack from above, then manipulate the shells in their mouths until they were able to deliver a crushing blow to destroy the body chamber and eat the ammonite.

[Ruger9a]

Yes, I see what you are talking about on your specimen.  It's a curious situation for sure. 

[pachy-pleuro-whatnot-odon]

On 12/7/2020 at 12:43 AM, grandpa said:

Notice there are two "types" of bite marks featured in the images: (1) One group has been attacked in the ventral region and looks like your example above and is often found in Lyme Regis.  It is attributed by some to be an attack by other cephalopods (e.g., squid) and by others to be large fish or mosasaur attack.

I guess the mosasaur hypothesis doesn't apply to the Lyme Regis specimens, though, seeing as I think fossilised ammonites would've been even tougher to chew on than "fresh" ones

 

On 12/7/2020 at 11:36 AM, RuMert said:

The shells were probably thin enough to provide buoyancy, hardened by curvy chamber walls - but the bite was targeted at the living chamber with no walls. Ventral bite severed several key muscles and the ammo body fell out of the shell

If anything like present-day nautiloids then these shells are indeed incredibly frail if hit at the right spot. I had one of those shells at one point, then my wife dropped something on exactly the living chamber - not even anything that heavy - and a giant whole immediately formed...