Náttúrufræðingurinn - 2001, Blaðsíða 32

Spárck, R. & Thorson, G. 1933. Marine gastro-
poda prosobranchiata. The Zoology of the
Faroes 3(1). 1-45.
Spjeldnaes, N. & Henningsmoen, K.E. 1963.
Littorina littorea: An indicator of Norse set-
tlement in North America? Science 141.275-
276.
Thorson, G. 1941. Marine gastropoda proso-
branchiata. The Zoology of Iceland 4 (60). 1-
150.
Vermeij, G.J. 1982. Environmental changes and
the evolutionary history of the periwinkle
(Littorina littorea) in North America. Evolu-
tion 36. 561-580.
Wagner, F.J.E. 1977. Recent mollusc distri-
bution patterns and palaeobathymetry,
southeastern Beaufort Sea. Canadian journal
of Earth Sciences 14 (9). 2013-2028.
West, R.G., Funnell, B.M. & Norton, P.E.P.
1980. An early Pleistocene cold Marine epi-
sode in the North Sea: Pollen and faunal as-
semblages at Covehite, Suffolk, England.
Boreas 9 (1). 1-10.
Wood, S.V. 1848. A monograph of the Crag
Mollusca. 1. Univalves. The Palaeontographi-
cal Society, London. 208 bls.
Woodward, B.B. 1913. The life of Mollusca.
Methuen, London. 158 bls.
Zaslavskaya, N.I., Sergievsky, S.O. &
Tatarenkov, A.N. 1992. Allozyme similarity
of Atlantic and Pacific species of Littorina
(Gastropoda: Littorinidae). Journal of
Molluscan Studies 58. 377-384.
Þorleifur Einarsson, Hopkins, D.M. & Doell,
R.R. 1967. The stratigraphy of Tjörnes north-
ern Iceland and the history of the Bering Land
Bridge. í: The Bering Land Bridge (ritstj.
D.M. Hopkins). Stanford University Press,
Stanford. Bls. 312-325.
Þorvaldur Thoroddsen 1892. Postglaciale marine
Aflejringer, Kystterrasser og Strandlinier i Is-
land. Geografisk Tidsskrift 11.209-225.
■ SUMMARY
The mesogastropod Littorina littorea
(Linné, 1758) in Iceland:
PALAEOBIOGEOGRAPHYAND MIGRATION
The periwinkle Littorina littorea (Linné, 1758)
has not been found living at present in Iceland
The only confirmed occurrence of the species in
Iceland is in the Middle Pleistocene upper littq
ral conglomerate in Búlandshöfdi, Snæfellsnes
west Iceland. These layers were deposited dur-
ing an interglacial, slightly older than 1.1 Ma.
The species apparently evolved from the Pacific
L. squalida Broderip and Sowerby, 1829, during
the trans-Arctic-North Atlantic migration from
the Pacific as a result of cooling. The oldest fos-
sil occurrence of the species is in the British Red
Crag, 2.4-2.55 Ma old, and it has not been found
in the Pliocene Tjörnes deposits in north Iceland
which are older than 2.6 Ma. This indicates that
the species separation postdates the deposition
of the uppermost Serripes Zone of Tjörnes, af-
ter the tide of the migration wave passed Iceland
but before it reached the North Sea area and Brit-
ain.
PÓSTFANG HÖFUNDA /AUTHORS'ADDRESS
Ólöf E. Leifsdóttir
Netfang/e-mail: oel@rhi.hi.is
Leifur A. Símonarson
Netfang/e-mail: leifuras@raunvis.hi.is
Raunvísindastofnun Háskólans
/Science Institute
Jarðfræðahús Háskólans
IS-101 Reykjavík
110