Results of theropod specimen BMR P2002.4.1.

<p>A) Theropod bone sample prior to EDTA demineralization. Scale bar equals 5 cm. B) Partial demineralization of theropod sample, showing “etched” vessels released during demineralization. Scale bar equals 1 mm. C) Release of resistant vessels from fossil bone. Scale bar equals 1 mm.</p

SEM and EDS results of <i>G. gallus</i> control sample.

<p>A) SEM image of primary soft tissue in <i>G. gallus</i> control sample with primary blood cells observable. B) EDS results of primary soft tissue in <i>G gallus</i> control sample showing a high abundance of carbon.</p

Bone samples and PLFA results.

<p>Bone samples and PLFA results.</p

SEM and EDS results of ceratopsian specimen BMR P2006.4.1.

<p>A) SEM image at 650× magnification of pliable ceratopsian vessels. B) SEM image at 4,500× magnification of framboids identified in pliable ceratopsian vessels. C) EDS signature of framboids, rich in iron.</p

Higher magnification SEM images of biofilm growth on extant <i>G. gallus</i> bone.

<p>A) Biofilm on inner pore surface. B) Higher magnification of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0013334#pone-0013334-g007" target="_blank">Figure 7A</a>, showing individual bacterial cells and EPS. Debris and diatoms are adhered to the biofilm. C) Biofilm surrounding surface pore and clean bone surface. D) Higher magnification of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0013334#pone-0013334-g007" target="_blank">Figure 7C</a>, showing biofilm on inner pore surface.</p

Examples of biofilm infiltration classes for extant archosaur bone.

<p>A) Class 0: a pore on a fractured bone sample from <i>A. mississippiensis</i> showing no biofilm infilling; B) Class 1: a pore on a fractured bone sample from <i>A. mississippiensis</i> showing a biofilm coating the inner pore wall; C) Class 2: pores from a whole bone sample of <i>A. mississippiensis</i> showing a significant biofilm coating on the inner pore walls; D) Class 4: a pore from a fractured bone sample of <i>G. gallus</i> showing a complete infiltration or covering of the pore. All images shown at 300× magnification.</p

Histograms of (A) pore size distributions and (B) pore infiltration distribution among extant archosaur samples.

<p>Histograms of (A) pore size distributions and (B) pore infiltration distribution among extant archosaur samples.</p

Results of PC-ORD statistical analysis.

<p>Testing for significant differences in the amount of PLFA assemblages in each sample, these results show a significant difference between samples of whole bone from aerobic conditions (2W) and fractured bone from aerobic conditions (2H), suggesting a difference in microbial communities due to bone condition prior to placement in the cenote. Axis 1 is based on variation in cenote environmental conditions, while Axis 2 is based on whole or fractured bones.</p

Ceratopsian specimen BMR P2006.4.1 bone fragments.

<p>A) Bone fragments prior to demineralization. Scale bar equals 5 cm. B) Light microscopy image of ceratopsian sample after demineralization, revealing a network of pliable, how vessels and tubes. Scale bar equals 1 mm. C) SEM image of pliable ceratopsian extracts at 4,500× magnification. D) EDS signature of SEM image 12(C), high in carbon, iron, and silica.</p

Results of thescelosaur specimen BMR P2006.4.309.

<p>A) SEM images of thescelosaur samples prior to demineralization. Scale bar equals 10 cm. B) Thescelosaur samples at 330× magnificaiton, showing bacterial cells filling the surface pores. C) Thescelosaur samples at 2200× magnification, showing the mineralized bacterial cells in fossil specimens. D) EDS results of the mineralized bacterial cells in fossilized thescelosaur samples, showing a Ca- and P-rich signature.</p