Discussion in 'Cephalopod Fossils' started by Hajar, Jan 6, 2011.
Just saw this on synchrotron imaging of ammonite mouthparts.
Great stuff Hajar!!
Stuck by Kevin, tweeted by me - thanks Hajar!
Love the London bus smiley; it was only a matter of time. :)
This has got to be the most astounding image of ammonite 'teeth' yet revealed - surely. I wonder how they compare to Nautilus radula teeth?
A nice little video is available here that helps make sense of the position of the teeth:
Amazing. Had to watch that one twice to wrap my brain around it. Very cool - thanks Phil!
"Outside of cephalopods, the radula in Baculites most closely resembles that in heteropod mollusks (multicuspidate, with sabrelike marginal teeth); they feed on plankton and gelatinous prey (18)."
Cool stuff. Bootleg PDF attached.
A few cephalopod radula images...
The top image is a Nautilus radula, the bottom is octopus.
Another article for those who really want to learn about cephalopod radula...
Thanks for the papers CG and Hal.
This leads to speculation on the arms and webbing... a large net to capture plankton? Or dangling down like Jellyfish with some kind of stickum?
Yes, thanks Hallucigenia and cuttlegirl for the papers.
The images are wonderful.
Overall this supports the consensus of the past couple of decades (e.g. Morton & Nixon 1987, Seilacher 1983, Kennedy et al. 2002, etc.), so no great revelations here. I don't remember seeing the link between diet and end-Cretaceous extinction spelled out before though (scavenging nautilids sail right through).
This was Morton & Nixon (1987): ".. the function of the large shovel-like lower jaw was the collection of large numbers of small prey. The bluntness of the beaks makes them unsuitable for biting (KAISER & LEHMANN, 1971, 29–30), and the apparent absence of distinctive areas of either lower or upper jaw for insertion of strong muscles indicates that a crushing or shearing action is unlikely. However, the broad rounded surfaces of the lower and upper jaws brought closer together by vertical and/or lateral movement to one another would, together with the actions of the buccal complex, provide an ideal
mechanism for the expulsion of large volumes of water while retaining trapped prey.”
Seilacher (2007), (in your trace fossil book, Kevin) writes " .. no one has ever found impressions of the arms, which were probably reduced to a delicate filter fan."
This is definitely the microscope of the future! With on-line media sharing so wide spread, hopefully we will see more rederings like this of all sorts of things. Hopefully it will be like sonograms and become a must have for many labs.
It is a wonderful tool D. See this from a few years ago on imaging of fossil insects in opaque amber.
Great thread, so much to learn!
This was really interesting. I wasn't aware that despite the abundance of ammonite fossils, we know so very little about them or their life history.
i must say, the radular teeth of this baculite look a lot like the teeth of conodont fish http://www.lifebeforethedinosaurs.com/2011/12/conodonta.html
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