Melissa Regan1, Lesley Gregoricka1, Jaime Ullinger2, Mark Schurr1, and Susan Guise Sheridan1

1
Melissa Regan1, Lesley Gregoricka1, Jaime
Ullinger2, Mark Schurr1, and Susan Guise
Sheridan1 1Department of Anthropology,
University of Notre Dame 2Department
of Anthropology, Ohio State University
C/N ratios were within the acceptable 2.9-3.6
range for all 81 samples, indicating good protein
preservation (Keegan, 1989). As seen in figure
2, the range of ?13C was -20.6 to -15.4 (n81
x-19.00.7), and the ?15N range was 7.2 to
14.7 (n81 x10.01.5). Table 1 includes all
the ?13C and ?15N comparisons for the Byzantine
St. Stephens collection.
?13C
?15N
?N
?N
?C
?C
Variation by Sex Statistical analysis of
bicondylar breadth showed a highly significant
difference between femora designated male and
female (p0.0005, df36 t3.5). The ?13C range
of all males fell between -20.6 and -15.4 (n42
x-19.00.8), -19.6 to -18.3 (n8 x-19.00.4)
for the females. Male ?15N values were 7.3 to
14.7 (n42 x9.91.4), females 7.5 to 11.6
(n8 x9.41.3). Figure 3 illustrates the
male/female stable isotope distributions at St.
Stephens. Male femora ?13C ranged from -20.6 to
-15.4 (n34 x -19.00.8), females from -19.6
to -18.3 (n4 x9.61.7). Male femur ?15N
fell between 7.3 and 14.7 (n34 x 9.81.5),
females from 7.5 to 11.6 (n4 x9.61.7). The
male innominate ?13C values were -20.0 to -18.5
(n8 x-19.10.5) females ranged from -19.3 to
-18.5 (n4 x-19.00.3). Male and female
innominate ?15N values were 9.1 to 12.2 (n8
x10.61.1) and 8.1 to 10.7 (n4 x9.21.0),
respectively. There was a significant
difference in ?15N values by sex for the
innominates (p0.02 df10 t2.2). These
results might reflect a higher trophic level for
male diets compared to females, but this is much
more likely a sex-related metabolic difference
(Schurr and Powell 2005). Also, it is important
to note that sex determination for the ilia was
limited to auricular surface elevation and
sciatic notch width because all of the
innominates were broken. The reliance on less
specific sex determination methods is worth
noting. The femora, assessed using both metric
and non-metric sex indicators and a larger sample
size, demonstrated no significant sex difference
(p0.4 df36). Age Variation Individuals
were divided into three broad categories for
comparison of stable isotope variation by age
infants, juveniles, and adults (Figure 4). The
?13C ranged from -19.5 to -17.8 (n5
x-18.40.6) for infants, -19.6 to -18.4 (n6
x -18.9 0.4) for juveniles, and -20.6 to
-15.4 (n69 x-19.00.7) for adults. The
combined subadult (infants plus juveniles) ?13C
values spanned from -19.7 to -17.8 (n12 x-18.6
0.6). For ?15N, infants ranged from 10.7 to
13.3 (n5 x12.61.0), juveniles from 7.2 to
11.3 (n6 x9.61.3), adults from 7.3 to 14.7
(n69 x9.81.3), and subadults from 7.2 to
13.3 (n12 x11.01.9). There was a
significant difference by age for both stable
isotopes in the St. Stephens collection. When
combined as subadults, infants and juveniles
showed a significant difference in ?15N (p0.03
df79 t1.7) and ?13C (p0.02 df79t1.9)
values compared to adults. The ?15N differences
between the two subadult groups resulted from the
elevated infant nitrogen levels, reflecting a
diet of breast milk enriched in 15N. The infant
samples
?N
?C
?N
?C
Figure 4. Distributions of ?13C and ?15N values
by age (innominates only).