What a very interesting find! I bet Duane Nash of http://antediluviansalad.blogspot.com will be salivating over this, given that he argued for omnivorous ankylosaurs in the past, a hypothesis that I think he might well be correct in suggesting. Certainly, a piscivorous ankylosaur would more likely evolve from omnivorous ancestors than from herbivorous ones. That being said, I do wonder if the actual gut contents might not be misleading in suggesting piscivorous specialisation; I could just as easily imagine a decidedly unfussy eater finding dead fish (perhaps after spawning?) and gourging itself on them and dying soon afterwards, thus merely making it seem as if fish were the mainstay of its diet when they were more like a seasonal boon or a result of opportunism. Aquatic specialisation on the other hand might point to actual piscivory. Even so, I think we should be aware of the caveat that a conclusion of piscivory might have led the authors into shoehorning _Liaoningosaurus_' oddities into aquatic adaptations which they might not actually be.
I think it is worth mentioning that according to Victoria Arbour, who researches ankylosaurs, Little L's plastron is actually misidentified belly scales (see https://pseudoplocephalus.com/2014/04/02/scaling-up/). I have no opinion on the matter.
Lastly and most out there, an aquatic _Liaoningosaurus_ might also be an alternative explanation for its lack of preserved integument if this was actually a derived, naked-bodied ornithischian that had lost all integument because of adapting said lifestyle. Does the critter hail from rocks that preserve soft tissue impressions, most notably feathers, or is this a moot suggestion of mine anyway?
Van: firstname.lastname@example.org <email@example.com> namens Clair Ossian <firstname.lastname@example.org>
Verzonden: zondag 28 augustus 2016 14:20
Aan: email@example.com; firstname.lastname@example.org
Onderwerp: Re: [dinosaur] Liaoningosaurus ate fish (!!??)
Can someone provide copies of BOTH of these papers in pdf form, please?
Clair R. Ossian, PhD
Professor, Geology, Emeritus
Tarrant County College-NE
2805 Raintree Drive
Carrollton, TX 75006
From: Tim Williams <email@example.com>
To: dinosaur-l <firstname.lastname@example.org>
Sent: Sun, Aug 28, 2016 12:40 am
Subject: Re: [dinosaur] Liaoningosaurus ate fish (!!??)
Two years ago I suggested that _Liaoningosaurus_ might have been an
amphibious ankylosaur (an 'aqua-ankylosaur'):
"Finally, I've wondered if the peculiar ankylosaur _Liaoningosaurus_
might have been amphibious, on account of its extensive ventral armor
(abdominal plate). In turtles (Testudinata), the evolution of a
ventral dermal armor (plastron) has been used as an indicator of
aquatic habits (e.g., Rieppel and Reisz, 1999; Li et al., 2008 - the
description of _Odontochelys_)."
Nevertheless, I concluded:
"But on the basis of ventral armor alone, even I'd say that the concept
of _Liaoningosaurus_ as an 'aqua-ankylosaur' is a stretch."
I'm very happy to be proven wrong here. Maybe it's not a stretch
after all. I'm fascinated by the proposition that _Liaoningosaurus_
was an aquatic/amphibious, fish-eating ankylosaur. In addition to the
presence of ventral armor plate (but no dorsal armor), Ji et al.
(2016) propose that the loose "sacrum-pelvic connection" was also an
aquatic adaptation, rather than a juvenile trait. Time will tell if
the 'aqua-ankylosaur' hypothesis stands up for _Liaoningosaurus_.
Maybe the ankylosaur _Sarcolestes_ ("flesh-robber") is worth another
look... was Lydekker correct after all in interpreting it as a
carnivore? I doubt it, but stranger things have happened.
On Sun, Aug 28, 2016 at 3:08 PM, Alberta Claw <email@example.com> wrote:
> Another new... uh, paper...
> Q. Ji, X. Wu, Y. Cheng, F. Ten, X. Wang, and Y. Ji (2016)
> Fish hunting ankylosaurs (Dinosauria, Ornithischia) from the Cretaceous of
> Journal of Geology 40: 183-190
> DOI: 10.3969/j.issn.1674-3636.2016.02.183
> All ornithischian dinosaurs are herbivorous or omnivorous. Ornithischian
> Liaoningosaurus paradoxus Xu et al., 2001 is an ankylosaur. Here we report a
> new specimen of L. paradoxus from China. It contains a number of fish
> skeletons. We interpret those remains as stomach or gut contents and hence
> as strong evidence for the meat-eating diet of the dinosaur. With elongate
> and fork-like denticles of cheek tooth crowns, L. paradoxus has a dentition
> capable of penetrating into animals like small fishes. The carnivorous
> adaptation of the dinosaur is also supported by the ungual modification to a
> sharp claw in both the fore- and hind-limbs. The evolution of a shield-like
> ventral armor plate and the loose sacrum-pelvic connection suggest that L.
> paradoxus may have adopted an aquatic way of life, using the ventral armor
> plate to protect the body from underwater attacks; as such, the open suture
> between the neural arch and centrum of the vertebrae cannot be used to
> indicate the juvenile nature of the type specimen. L. paradoxus is the first
> carnivorous ornithischian dinosaur since dinosaur was first known in the
> 18th century and represents not only the first aquatic or semi aquatic
> example of armored dinosaurs but also the smallest species of ornithischian
> dinosaur so far known.
> This finding clearly vindicates the premise of this bizarre novel.