Comments on: Limusaurus – an herbivorous ceratosaur?

By: The carnivorous dinosaurs who turned vegetarian | My Blog

The carnivorous dinosaurs who turned vegetarian | My Blog — Wed, 27 Feb 2013 03:35:51 +0000

[...] others, for the record, are the odd little Limusaurus and the long-legged ostrich-like ornithomimosaurs (though one of their number seems to have been a [...]

By: Übergangsfossilien | kěrěng

Übergangsfossilien | kěrěng — Sun, 16 Dec 2012 16:09:12 +0000

[...] Der Frame-Shift wurde nun bestätigt: http://www.sciencedaily.com/releases/2011/09/110904140359.htm http://archosaurmusings.wordpress.com/2009/06/18/limusaurus-%… http://archosaurmusings.wordpress.com/2009/06/18/limusaurus-%… [...]

By: Guest post: Haplocheirus – the skilful one « Dave Hone’s Archosaur Musings

Fri, 29 Jan 2010 00:45:17 +0000

[...] and serrated like steak knives. Some theropods have lost their teeth (e.g., most ornithomimosaurs, Limusaurus), and a select few theropods have numerous small teeth (Shuvuuia, an early ornithomimosaur named [...]

By: Some Limusaurus images « Dave Hone’s Archosaur Musings

Some Limusaurus images « Dave Hone’s Archosaur Musings — Sat, 19 Dec 2009 07:12:21 +0000

[...] little Limusaurus has gained a fair bit of attention on here this year, what with it being a herbivorous ceratosaur (and thus some interesting prospects for theropod diets), having interesting hand homology [...]

By: diborane » Ornithomimosauria

diborane » Ornithomimosauria — Sun, 05 Jul 2009 18:57:46 +0000

[...] Limusaurus – an herbivorous ceratosaur? « Dave Hone's Archosaur … [...]

By: Jura

Jura — Wed, 24 Jun 2009 02:00:42 +0000

Geez David,, was this not just run around on the DML.

Like others, my evidence for a muscular gizzard comes from Bakker’s Heresies. Bakker is, admittedly, prone to romanticisms, so it is possible that he didn’t see what he described (and it certainly wouldn’t be the first mistake found in Heresies).

However, there are other studies that suggest that the role of gastroliths is a digestive one.

Namely:

Fitch-Snyder, H. and Lance, V.A. 1993. Behavioral Observations of Lithophagy in Captive Juvenile Alligators. J. Herp. 27(3):335-337

As I wrote on the list, these alligators were observed actively seeking out stones to ingest, only after they had eaten their meals. That gastroliths appear not to aid in digestive speed, or efficiency, suggests that this may be a “vestigial behaviour.”

I find the issue of ballast in crocodylians to be suspect both because of the association of the aforementioned behaviour, with feeding, and because stomach stones contribute very little to overall body weight.

Brazaitis (1969) observed stomach contents of captive crocodylians, and reviewed gastrolith studies in wild crocs. In all cases, stomach stones made up ~1% of total body mass. It’s hard for me to imagine that 1% being so integral.

Brazaitis, P. 1969. The Occurrence and Ingestion of Gastroliths in Two Captive Crocodilians. Herpetologica 25(1):63-64.

By: David Marjanović

David Marjanović — Tue, 23 Jun 2009 13:24:44 +0000

I would like to point out that extant crocodylians employ gastroliths for digestion (and not just for ballast, as is often presumed).

Evidence?

At the SVP meeting last year, an X-ray movie was shown that showed gastroliths lying around in an alligator stomach and doing nothing while an entire rat was being digested.

By: Limusaurus – four fingers and a whole mess of homologies « Dave Hone’s Archosaur Musings

Tue, 23 Jun 2009 11:21:16 +0000

[...] digits, Dinosaurs, evolution, fingers, Limusaurus, theropods OK, so Limusaurus was, bizarrely, a basal herbivorous ceratosaur from the Middle Jurassic of China, but what is all this manual homology stuff that seems to be exciting everyone? Well, it is quite [...]

By: Limusaurus confusion « Dave Hone’s Archosaur Musings

Limusaurus confusion « Dave Hone’s Archosaur Musings — Tue, 23 Jun 2009 08:40:13 +0000

[...] Tags: archosaurs, Limusaurus The advent of the description of Limusaurus and the associated hypothesis of digit homologies in the paper is likely to generate quite a lot of interest in dinosaurian and avian circles. [...]

By: David Hone

David Hone — Tue, 23 Jun 2009 06:50:43 +0000

Speaking for Paul and having had a conversation over this very taxon a while back I think he just might. Not that I am trying to establish either a) Paul’s position, or b) his wagering skills vis-a-vis his property without his consent.

By: David Hone

David Hone — Tue, 23 Jun 2009 06:45:21 +0000

Just checked the actual paper (like, duh) and it says 1.7 m, so I was pretty much bang on.

By: David Hone

David Hone — Tue, 23 Jun 2009 06:43:01 +0000

I think that is an accurate perception Brian and probably comes from that fact that primitively, most tetrapods were carnivores (well meat-eaters of some kind, be it fish or insects or whatever). Most fish eat other fish, or at least animalian life of some kind, as do most amphibians and reptiles. Thus conversion to herbivory from carnivory is the norm and the reverse is quite rare (and generally via omnivory, which makes a lot of sense intuitively).

By: David Hone

David Hone — Mon, 22 Jun 2009 23:47:45 +0000

Sorry I deleted them from the images (I can’t think why now). It’s small – Caudipteryx sizes, say 2m ish with a tail.

By: David Hone

David Hone — Mon, 22 Jun 2009 23:46:29 +0000

True, but the beak and other features do imply herbivory, and certainly crocs employ relatively large stones (as I understand) compared to these very small gravelly ones.

By: David Hone

David Hone — Mon, 22 Jun 2009 23:45:06 +0000

Well that is nature for you, you only get a limited amount of space in the main text and when you have to inlcude herbivory and homologies in there too you run out of room fast. However the online supplementary material is most extensive and covers this is some detail.

By: Tim Williams

Tim Williams — Sun, 21 Jun 2009 04:07:29 +0000

I agree with you Paul, 100%. However, would you bet your house on _Eshanosaurus_ being a therizinosauroid?

On your other point.. yep, without good cranial material, dietary habits are an open question for these taxa. I expanded on this a bit here:

http://dml.cmnh.org/2009Jun/msg00188.html

By: Paul Barrett

Paul Barrett — Sat, 20 Jun 2009 12:41:12 +0000

If Eshanosaurus is an Early Jurassic therinosauroid as some of the authors on the Limusaurus paper contend, then this taxon is actually the earliest theropod herbivore. A point conveniently overlooked when writing the Limusaurus paper? Just teasing.

As for gastroliths, it’s worth noting that we know nothing about the cranial morphology of most of the taxa mentioned and in the case of Baryonyx, there were only a couple of pebble associated with the skeleton, that may or may not be gastroliths.

By: Dinosaur Finger Points to Bird Evolution | Dinosaur Tracking

Dinosaur Finger Points to Bird Evolution | Dinosaur Tracking — Fri, 19 Jun 2009 14:41:06 +0000

[...] Archosaur Musings [...]

By: Christophe Hendrickx

Christophe Hendrickx — Fri, 19 Jun 2009 09:36:57 +0000

I believe Baryonyx has never been found with gastroliths in its gut content. Am I wrong ?

By: On digits and diets. « The Theatrical Tanystropheus

On digits and diets. « The Theatrical Tanystropheus — Fri, 19 Jun 2009 06:07:10 +0000

[...] For starters, as Dave Hone writes, it was probably strongly herbivorous. [...]