Supplementary Figure
1. Representative petrographic images of specimens from
Mongolia.
Eggshells are 0.7 to 1.6 mm thick.
Panels A-D are typical transmitted and
polarized light images of oviraptorid eggshells from Ukhaa Tolgod. A-B illustrate an
apparently well preserved specimen. C-D illustrate a sample with
two
layers of structural
calcite, an outer layer with some quartz sand grains adhering to the eggshells illustrating
that some alteration of the very outer surface of the eggshell might have occurred,
at
which point sand grains may have attached. We expect that this outer surface would have
been removed during the drilling protocol used. E-F are typical images of a Djadokhta
Morphotype 2 eggshell. The transmitted light shows light areas within the main eggshell
structure which are indicative of areas of dissolution and replacement, which is also seen
in the polarized light image. This is the primary reason for considering these specimens
as uncertain of poor preservation. Cathodoluminescence images of Mongolian eggshells
are not shown, as there was no significant florescence in any of the samples examined.
Panels G-I show SEM images of oviraptorid eggshells. Panel G shows a specimen with
large grains attached to its interior surface. These are shown to be quartz sand grains by
EDS analysis and are removed by drilling before analysis. H and I show a specimen
displaying apparently excellent preservation with little evidence for dissolution on the
outer surface evidenced by prominent eggshell surface features. This cross section also
illustrates an important feature of this eggshell type, namely that pore canals such as the
one evident are small and rare, so do not act as focal points for dissolution and secondary
mineral precipitation. Panel I is a close up of the pore canal which is found not to have
been infilled with secondary material or host matrix.
Supplementary Figure 2. Representative petrographic images of specimens from
Argentina and other sites.
Eggshells are 1 to 2 mm thick. Panels A-F are images of
Auca Mahuevo eggshells. Panel A and B show thin section transmitted light and
cathodoluminescence images of typical egg-bearing layer 2 eggshells. Substantial
dissolution and reprecipitation of carbonate on the eggshell inner surface is apparent,
particularly surrounding calcite nucleation centers. On the outer surface dissolution and
reprecipitation is still apparent but not as extensive as the inner layer. Panels C-D are
SEM images of a layer 2 eggshell showing extensive blocky calcite on the inner eggshell
surface. Panel E and F are SEM images of a typical layer 4 eggshell. Surface
ornamentation is noticeably more prominent than in the layer 2 specimen and blocky
calcite also less apparent. Panel F represents a higher magnification image of a pore canal
opening shown in E. Blocky material at the entrance to pore canals was revealed to be
silica rich clay minerals rather than secondary calcite by EDS analysis. Panel G is a
polarized light image of a thin section of a Faveolithid eggshell from Rio Negro
Argentina showing extensive evidence for dissolution and replacement/recrystallization.
Panel H is a polarized light image of an eggshell from the Two Medicine formation in
Montana that has been described as being of the parataxonomic group Spheroolithidae. In
this case the eggshell is more intact but pore canals are infilled with calcium carbonate,
which is fluorescent under CL (not shown). Panel I is a transmitted light image of a
Megaloolithid eggshell from Ningxia in Mongolia, also showing extensive evidence for
diagenesis and replacement.
Supplementary Figure 3. Representative petrographic image of specimens from
France.
Eggshells are typically 1.2 to 2 mm thick. Panels
A-C show transmitted light,
polarized light and cathodoluminescence images of a Rousset level B eggshell.
Cathodoluminescence reveals pervasive alteration of this specimen. Specimens showing
high levels of fluorescence like this are in the minority at Rousset. Panels D-F is a more
typical example of a Rousset eggshell (including level A), with analysis of thin sections
showing clear evidence for secondary carbonate precipitation localized to pore canals and
the very outer surface of the eggshell but not the main structure of the eggshell. Panels G
and H are SEM images of Rousset level B and A eggshell respectively. Blocky
(presumably secondary) carbonate is visible around pore canal openings and on the
underside of the eggshell in the level B specimen in particular. However eggshell
structural features appear intact. Panel I is a higher magnification image of the pore canal
opening in Panel H. Blocky material infilling the pore canal is identified as carbonate by
EDS analysis.
Supplementary Figure 4. Trace element and isotopic composition of material from
Mongolia.
Panels A and B show stable isotope data for all Mongolian samples and
illustrate the separation of carbonate nodules and diagenetic phases from some, but not all
eggshells. Oviraptorid eggshells with stable isotopic compositions approaching those of
carbonate nodules, spar calcite, and bone.
Δ
47
temperatures in this plot are calculated
using the Caltech calibration line for biogenic carbonate that is slightly shallower than the
Ghosh et al. inorganic calibration
25,30
. Panels C-E illustrate that at this site there is no
strong correlation between trace element contents and the wide range in oxygen isotope
compositions of materials at this site and we take this to be an indication that trace
element content is not providing strong indications of preservation/diagenesis at this site.
Supplementary Figure 5. Trace element and isotopic composition of material from
Argentina.
Panels A and B illustrate that Auca Mahuevo layer 2 eggshells are only
marginally different in bulk isotopic composition than layer 4 eggshells and both are very
different from measurements made on bulk sediment from the site. However
Δ
47
temperatures are significantly higher in layer 2 eggshells. Panel C shows that a strong
correlation exists between
Δ
47
temperature and Li/Ca in Auca Mahuevo samples, a
possible indication that lithium contents may be indicative of eggshell recrystallization in
layer 2 specimens. Eggshell specimens that are higher in lithium are also higher in
magnesium although manganese appears to be less diagnostic, as shown in panels D-E.
Supplementary Figure 6. Trace element and isotopic composition of material from
France.
Panels A and B illustrate that eggshells from Roques Hautes and Rousset levels
C-D all have very similar isotopic compositions to soil carbonates. In contrast, Rouss
et A
eggshells clearly are distinct in their composition compared to soil carbonates. Panels C-
E illustrate that Rousset A specimens are higher in strontium than other materials, but
generally lower in manganese and lithium, and marginally lower in iron. This pattern
could potentially be consistent with loss of strontium but gain of other elements due to
diagenesis of eggshells. However it could also represent different modes of alteration in
-15
-13
-11
-9
-7
-6
-4
-2
0
2
Rousset A Eggshell
Rousset C-D Eggshell
Roques Haute Eggshell
Roques Haute Soil Carbonate
δ
13
C (V-PDB)
δ
18
O
Mineral
(V-PDB)
-15
-13
-11
-9
-7
-6
-4
-2
0
2
δ
13
C (V-PDB)
δ
18
O
Mineral
(V-PDB)
0.0
0.5
1.0
1.5
2.0
2.5
0
5
10
15
20
Sr/Ca (mmol/mol)
Fe/Ca (mmol/mol)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
0
1
2
3
4
5
Sr/Ca (mmol/mol)
Mn/Ca (mmol/mol)
30
35
40
45
50
55
-6
-4
-2
0
2
4
6
8
10
Δ
47
Temperature (°C)
δ
18
O
H20
(V-SMOW)
0.0
0.5
1.0
1.5
2.0
2.5
0
50
100
150
200
Sr/Ca (mmol/mol)
Li/Ca (μmol/mol)
A
B
C
E
D
different stratigraphic layers, an interpretation favored by petrographic and EBSD
analysis (Supplementary No
te 3,
Supplementary
Fig
ure
4,
Supplementary
Fig
ure
7).
Supplementary Figure 7. EBSD
analysis of Rousset eggshells.
This analysis proved
instructive in interpreting Rousset eggshell geochemistry, with Rousset level A eggshells
clearly completely recrystallized (D-F). Rousset C-D eggshells yielded a very mixed
picture with some specimens showing excellent preservation, such as the one indicated
here in the upper panels (A-C). However other eggshells were clearly altered, for
example those shown in
Supplementary
Fig
ure
3.