Santander, February 19th-22nd 2008 - Aranzadi

MUNIBE(Suplemento/Gehigarria) - nº nº 3100 176-187 000-000 DONOSTIA-SAN SEBASTIÁN 2010 2003 D.L. ISSN SS-1055-2010
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Oysters ancient and modern: potential shape variation with habitat
in flat oysters (Ostrea edulis L.), and its possible use in archaeology
Ostras antiguas y modernas: variación potencial de la forma y
el hábitat de la ostra plana (Ostrea edulis L.) y su posible uso en Arqueología
KEY WORDS: Archaeology, Ostrea edulis, morphology, methodology, management.
PALABRAS CLAVE: Arqueología, Ostrea edulis, morfología, metodología, manipulación
GAKO-HITZAK: Arkeologia, Ostrea edulis, morfologia, metodologia, manipulazioa.
Greg CAMPBELL (1)
ABSTRACT
Recognition of two distinct shapes in shells of flat oyster (Ostrea edulis L.) from late 3 rd -4 th Century A.D. Winchester, central southern England,
prompted comparison with shapes of modern O. edulis samples across the Solent, and development of methods which define shell shape
objectively for this species, despite its notorious variability. Relative proportions in the plane of commissure were a more consistent means of
comparing shape than proportions based on maximum shell dimensions. Shell shape varied between harbours, near-shore and deeper water,
probably in response to differing bed currents. Archaeological shells changed abruptly during growth from a range of shapes to a single shape,
arguing for oyster management in late Roman England.
RESUMEN
A finales del siglo III y en el siglo IV d. C. se reconocen en Winchester, Centro-Sur de Inglaterra, dos formas distintas de la ostra plana
Ostrea edulis L. gracias a la comparación con las formas de ejemplares modernos procedentes del Estrecho de Solent. De esta forma se han
desarrollado métodos que definen la forma de la concha de esta especie de una manera objetiva, a pesar de su notoria variabilidad. Para
ello, se optó por tener en cuenta las proporciones relativas de la zona de la charnela, más que las dimensiones máximas de las valvas. El
tamaño de las valvas varía entre los puertos, en las áreas cercanas a la costa y en las zonas profundas, posiblemente como respuesta a las
corrientes del fondo del mar. Las valvas de las ostras del sitio arqueológico cambiaron de forma abrupta durante su crecimiento, de formas
variadas a simples, lo que puede interpretarse como un indicio de manipulación durante el periodo tardorromano en Inglaterra.
LABURPENA
K.o. III. mendearen amaieran eta IV.aren hasieran, Winchesterren, Ingalaterrako erdialde-hegoaldean, Ostrea edulis ostra lauaren bi forma
desberdin bereizi ziren, Solent itsasartetik hartutako ale modernoekin alderatuz. Espezie horretako maskorraren forma objektiboki zehazteko
medotoak garatu dira, espezie horren aldakortasuna nabaria den arren. Horretarako, txangaren guneko proportzio erlatiboak kontuan hartu
ziren, kuskuen neurri maximoak kontuan hartu beharrean. Kuskuen tamaina aldatu egiten da portu batetik bestera, kostatik hurbil eta gune sakonetan;
seguruenik, itsas hondoko korronteak direla eta. Leku arkeologikoko ostren kuskuak asko aldatu ziren hazten ari ziren artean, askotariko
formetatik forma sinpleetara, eta hori Ingalaterrako erromatar berantiarreko manipulazio-zantzu bat bezala interpreta daiteke.
1. INTRODUCTION
Oysters, marine bivalves of the Order
Ostreoida, are rough-shelled inequivalve monomyarian
epi-faunal filter-feeders which live cemented
by the larger left valve to reasonably stable surfaces
where current speeds are not extreme.
Oysters are large, delectable, accessible, and
often densely packed, sometimes forming reefs,
so they are consumed by humans around the
world, and have been for thousands of years (See:
Waselkov 1987). The main oyster of the European
Atlantic, the Baltic, the Mediterranean and the
Black Sea is the common, edible or flat oyster
Ostrea edulis Linnaeus, 1758 (Tebble 1966: 53).
The right valve is flat, and the left valve is cupped
(Tebble 1966: 53). In oysters, the hinge is not typical
of bivalves (Yonge 1960: 27), having a central
chondrophore flanked by flattened surfaces called
bourrelets (Stenzel 1971: 974). The visceral mass
is held in a bowl-like cavity in the left valve ventral
to the hinge, surrounded by the more gently sloping
mantle cavity; the ventral extent of the visceral
cavity is marked by the ventral edge of the single
adductor muscle scar (Yonge 1960: Fig. 9).
This oyster has been grown artificially since at
least Classical times (Pliny the Elder: Historia
Naturalis IX, 59). In later prehistoric and historic
periods in England, oysters were transported
regularly to sites inland (e.g. Winder 1988).
(1)
150 Essex Road. Southsea, Hants. U.K. PO4 8DJ (g.v.campbell @ btinternet.com).