Santander, February 19th-22nd 2008 - Aranzadi

Oysters ancient and modern: potential shape variation with habitat in flat oysters (Ostrea edulis L.), and its possible use in archaeology
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Figure 8. Archaeological O. edulis from Winchester AY93 late Roman pit fill
2239. (a): closure height as a function of closure length. (b): distribution of closure
HLR (Hc/Lc) with hinge-with ratio (Wh/Lc). Open triangles: oval morph;
solid dots: round morph.
Figure 7. Inside views of
an oyster (O. edulis) left
(lower) valve of median
shape from a series of
modern Solent samples:
adjusted to a common
arbitrary height. (a)
Portchester Lake, a small
harbour channel (Hmax:
63mm); (b) Fareham Lake,
a large harbour channel
(Hmax: 63mm); (c)
Gilkicker Point, near-shore
(Hmax: 65mm); (d) NW of
Ryde, Solent channel
edge (Hmax: 69mm); and
(e) West Ryde Middle
Bed, in Solent channel
(Hmax: 72mm).
bour lakes were thin, frilly-edged, occasionally
lobed with small triangular hinges, and shells tended
to become increasingly heavy, more streamlined
and broader- and straighter-hinged with increasing
distance from shore. Simple arithmetic ratios of
shell dimensions followed the same trends in shape,
with the relative width of the hinge showing the greatest
rate of change, and a statistically significant difference
between samples.The true nature of the
variation of shape with habitat has not been determined
by this study. The number of samples and
the numbers in each sample were small, and the
variability within a habitat was not tested by repeat
sampling.
The differences in shape might be caused by
hydrodynamic differences between oyster beds
(Fig. 9). In harbours, slow steady tidal flows produce
MUNIBE Suplemento - Gehigarria 31, 2010
S.C. Aranzadi. Z.E. Donostia/San Sebastián