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."