Clair R. Ossian, PhD
Professor, Geology, Emeritus
Tarrant County College-NE
2805 Raintree Drive
Carrollton, TX 75006
From: Tim Williams <firstname.lastname@example.org>
To: dinosaur-l <email@example.com>
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 <firstname.lastname@example.org
> 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.