Comments on: Buzzsaw Jaw Helicoprion Was a Freaky Ratfish

By: Gianluca Polgar

Gianluca Polgar — Tue, 12 Mar 2013 10:56:19 +0000

Is it possible it fed on shelled ammonoid cephalopods? The whorl seems to me to be precisely made as a can-opener for ammonites…

By: Judy Geniac

Judy Geniac — Sat, 09 Mar 2013 18:34:55 +0000

Ray Troll likely had a contagious fascination. Ever since I saw his exhibit at the Denver Museum of Nature and Science, I have been wondering if this puzzle got solved! Congrats to all! …. Best exhibit ever done at that museum.

By: 220mya

220mya — Wed, 06 Mar 2013 01:15:25 +0000

Charlie and SDurnell: At ~3:15 in this video, Ray Troll explains briefly how the whorl works: http://www.youtube.com/watch?v=94HFvSDWB2Q

By: Mark McMenamin

Mark McMenamin — Sat, 02 Mar 2013 23:20:45 +0000

This is a splendid and entirely plausible interpretation of the Helicoprion feeding strategy. The hard-to-fossilize nature of its inferred prey suggests that we have much to learn about Late Paleozoic soft-bodied cephalopods.

By: Tim

Tim — Fri, 01 Mar 2013 10:37:46 +0000

Chase: Squid and octopus-like fossils have been found in Mazon Creek, which is Carboniferous. Permian squid are likely to have existed. Especially since Orthocone nautiloids had the same arrangement of tentacles as squid do (10). Just because we don’t have many fossils of Permian squid does not mean that they don’t exist, indeed, their completely soft bodies with minimal calcification would mean that, if they were present with Helicoprion, not much of them would fossilise, if any, seeing as Helicoprion’s cranial cartillage was so well hidden by the Rock. Modern Nautilus are far more ancient in lineage than orthocones, which is why they have so many tentacles, as would seem to be primitive for cephalopods. Orthocones were essentially squid like in most pysical aspects, minus suckers and plus the chambered shell, since the Silurian, and gave rise to the squids, belemnites, octopus, and ammonites. When this occured is left tantalisingly un-clear, but since primitive squid appear in the triassic, they must have been present at least in the permian.

By: Wayne Itano

Wayne Itano — Thu, 28 Feb 2013 19:53:36 +0000

My reading of the journal article is that they are claiming Helicoprion is a Euchondrocephalan and stem-group holocephalan, not crown-group holocephalan. So calling Helicoprion a ratfish rather than some sort of a distant relation of a ratfish doesn’t seem quite right.

By: Mike Huggins

Mike Huggins — Thu, 28 Feb 2013 17:47:21 +0000

Brian – There were belemnites in the Permian?

By: Bombyx

Bombyx — Thu, 28 Feb 2013 16:03:26 +0000

I think that Helicoprion is not a crown holocephalan (holostylic euchondrocephalans), but a stem holocephalan, along with other autodiastylic euchondrocephalans, such as Debeerius. So, it is a crown chondrichthyan, as suggesting by teeth morphology.

By: David Marjanović

David Marjanović — Thu, 28 Feb 2013 13:44:39 +0000

I would assume that the spiral was NOT there at birth, and perhaps it formed over time. The tiny teeth could literally be it’s ‘baby teeth’ from when it was born and they just recycled around and around when new and bigger teeth came in as it grew!

That’s also what tuatara do, except in a straight line, not in a spiral: their teeth are fused to the jawbone, so they can’t be replaced, instead new teeth are added at the back. So, the baby teeth are near the tip (and eventually worn down to the bone), and the teeth get larger the farther back they are. Nothing moves, the jaw just grows at the rear end.

By: Alif Aufa

Alif Aufa — Thu, 28 Feb 2013 06:35:53 +0000

cool but creepy! freak encounters.