The Lark Quarry Trackway: Thulborn Strikes Back

UPDATE: I made a slight mix up when writing this article last week. I have stated that Thulborn, 2013 is responding to the claims of Romilio et al. 2012. This is actually incorrect. The paper to which Thulborn is responding is Romilio and Salisbury, 2011, where they dispute the identity of the large track maker at Lark Quarry and its consequences for the interpretation of the trackway. Thulborn has not yet responded to the new claims in Romilio et al. 2013, although he may do so in future. The core message of the article however is still the same. Romilio et al. do not believe that the trackway at Lark Quarry represents a dinosaur stampede, whereas Thulborn maintains it does. This intriguing topic will no doubt continue to provide ample material for debate in the years to come. This article has been edited from its original and second versions. For anyone who wants to see the original version, email me at the address at the top of the blog.

Regular readers of this blog (if there is such a thing) may recall that I wrote an article about a new paper by Romilio & Salisbury where they disputed the claims made by Tony Thulborn, who stated that the dinosaur trackways at Lark Quarry, Queensland were made by stampeding dinosaurs. In their paper they proposed that in fact the trackways were made at different times and showed dinosaurs crossing a river.

Perhaps a stampede after all? Thulborn certainly still seems to think so. Image from abc.net.au.
Perhaps a stampede after all? Thulborn certainly still seems to think so. Image from abc.net.au.

Now, Thulborn has responded to the claims made by Romilio & Salisbury, 2011, rejecting their analysis. In his rebuttal, Thulborn criticises their application of the multivariate analysis method, pointing out that they didn’t actually compare trackways of ornithopods and theropods but rather studied a single trackway, meaning that the only variation they could obtain would be between the individual tracks themselves. He also states that the multivariate analysis “appears to be based on fabricated data and is, therefore, worthless”.  The outlines of these tracks would have also deteriorated over time (Thulborn and Wade, 1984).

Thulborn also takes issue with how Romilio et al. have portrayed Thulborn’s initial interpretation of the site as a prey-pursuit scenario. Thulborn makes the distinction that he has never said it was this particular scenario (except when explicitly speculating), but rather that it was merely a stampede in general, regardless of the identity of the large track maker. Indeed, he argues that the whole premise of the recent paper by Romilio et al. seems to be to declare the larger tracks were in fact made by a large ornithopod, a fact that Thulborn declares is a “separate matter of secondary interest”.

So is the trackway at Lark Quarry evidence of a dinosaur stampede or not? Well, it depends on who you ask at the moment! Further study will no doubt show which of the two parties were closest to being correct. This debate is sure to continue; I’ll keep you all updated when the next developments arise!

References

Romilio A, S. W. Salisbury (2011) A reassessment of large theropod dinosaur tracks from the mid-Cretaceous (late
Albian-Cenomanian) Winton Formation of Lark Quarry, central-western
Queensland, Australia: A case for mistaken identity. Cretaceous research 32: 135-142.

Romilio A, Tucker, R. T. and S. W. Salisbury (2013): Reevaluation of the Lark Quarry dinosaur Tracksite (late Albian–Cenomanian Winton Formation, central-western Queensland, Australia): no longer a stampede?, Journal of Vertebrate Paleontology, 33:1, 102-120.

Thulborn, R.A. (2013): Lark Quarry revisited: a critique of methods used to identify a large
dinosaurian track-maker in the Winton Formation (Albian–Cenomanian), western Queensland, Australia, Alcheringa: An
Australasian Journal of Palaeontology, DOI:10.1080/03115518.2013.748482

Thulborn, R. A., and M. Wade. 1984. Dinosaur trackways in the Winton
Formation (mid-Cretaceous) of Queensland. Memoirs Queensland
Museum 21:413–517.