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Re: Dinosaur urine?

McCarville, K. & G.A. Bishop, 2002. To pee or not to pee: Evidence for liquid urination in sauropod dinosaurs. Journal of Vertebrate Paleontology 22: 85A.

One of North America?s most significant dinosaur trackway localities is in the Upper Jurassic
Morrison Formation within the Comanche National Grasslands along the Purgatoire River,
south of the town of La Junta, Colorado. The sedimentary rocks at this locality are interpreted
as having been deposited in a lacustrine environment. The Purgatoire Tracksite includes
five stratigraphic levels containing more than 1300 footprints attributable to about 100 individual
sauropod and therapod dinosaurs. At the top of Bed 2 is a surface that is marked with
40 sauropod trackways and 43 therapod trackways. At the same stratigraphic level is an enigmatic
bilaterally symmetric bathtub-shaped depression approximately 3 m long, 1.5 m wide,
and 25-30 cm deep whose origin has heretofore remained obscure. Based on examination of
a cross sectional view of the structure and comparison to similar experimental scours formed
in laminated sand at St. Catherine?s Island, Georgia, this structure is interpreted as a scoured
basin formed by a stream of fluid impinging on the sediment from above and filled with sediment
derived from within the basin itself. On the nearly flat lake shore, the only source of
such an elevated fluid stream would be animals crossing the area. The volume of fluid
required to form a scour structure as large as the one in question suggests it may represent the
expulsion of liquid urine from one of the sauropod dinosaurs crossing the tracksite.

From: Donna Braginetz <quailspg@frii.com>
Reply-To: quailspg@frii.com
To: DML <dinosaur@usc.edu>
Subject: Re: Dinosaur urine?
Date: Thu, 16 Mar 2006 13:11:42 -0700

Phil Bigelow wrote:

> Nonavian theropods would likely have had an excretory system similar to
> birds.  Non-theropod dinosaurs, that's anyone's guess.

A few SVP meetings ago there was a poster reporting on a bathtub-sized
depression which was interpreted as the possible result of a sauropod
voiding liquid urine. I don't recall the author's name or any other
details. Can someone fill us in?

-- Donna Braginetz