Were nautiloids responsible?

[Phil]

Studies of predation damage in Palaeozoic brachiopods have uncovered unidentifiable drill holes. Were nautiloids responsible?

Original report

 

[Fujisawas Sake]

Interesting article. But don't you think that's more of a gastropod mode of attack? Then again, how do nautiloids eat?

 

[Phil]

Could well be John. Octopus certainly leave drill holes in shells, I'm not sure how similar the radula was on a nautiloid to that of octopus though. They probably pretty much ate anything smaller than them and scurrying I'd imagine. Ordovician trilobites needed their defensive spines for some reason, and nautiloids were top predator...

 

[Fujisawas Sake]

Yeah, that is a good point. The Burgess Shale is full of pointy, spiky forms. Even ancient chitons had some nasty looking spines.

John

 

[Jean]

To chip in here () those holes look just like the ones we see in bivalves from our local oyster borer (Lepsiella scobina). It just looks gastropodish to me.

J

 

[Architeuthoceras]

I just had to check the no box. Why would anything spend the time to drill into a brachiopod? There is nothing (very little anyway) inside!

 

[Taollan]

Probably not...

While it could be a nautiloid, The holes don't seem right. Cephalopods drill bivalve shells in order to inject a venom that will kill or atleast nearly kill the animal inside, put them pull the shell and eat from the opened shell. This means that the hole needs to only be a pin prick. drilling as small of whole as you need with a radula will generally produce an oval drill. These holes seem to be more rounded and larger than one would expect from a hole merely intended for venom injection. This appears to be more like a gastropod drill, which feed through the hole rather than pulling the shell. This probably is not gastrood either, however, as drilling gastropods aren't thought to have evolved untill 110 million years ago, formly in the Mesozoic, long after these poor brachiopods met their fate.

 

[Jean]

ooooooooh the mystery drill!!! I wonder what our photoshop guru's can do with that!!!!

J

 

[Phil]

Methinks this paper cited below help us this case. Unfortunately it would cost a subscription to obtain it. Is there anyone out there who could gain a free copy via an educational institution who could help please?

http://www.blackwell-synergy.com/links/doi/10.1111/1475-4983.00065

 

[Jean]

Hi Phil,

Got it but it's too big to put on here (it's a 1.34 meg pdf file) I'll email it to you!

J