Fróðskaparrit - 01.01.2001, Blaðsíða 109

ARMFÓTINGAR (BRACHIOPODA) í FØROYSKUM ØKI
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An important part of the paper by We-
senberg-Lund (1941) for the present study
is the description of the two superficially
similar looking Terebratulina species. For
this purpose, Wesenberg-Lund used several
features pertaining to the morphology of
the shell. She concluded that the two
species either represented a morphological-
ly based cline with intermediate forms, or
were two different races (subspecies) cau-
sed by different ecological conditions. This
problem has since been investigated using
principal component analysis on a morpho-
logical study of the shells (Curry and Endo
1991) and DNA and immunological analy-
sis of the intracrystalline shell proteins (Co-
hen et al:, 1991). Both studies confirmed
the presence of two valid species with no
intermediate forms.
In 1990, the present author published a
paper concemed with the application of
brachiopods in palaeoceanographic recon-
structions (Thomsen, 1989). This paper
dealt mainly with Macandrevia cranium
(Miiller, 1776) and established the recent
biogeography of this species based on pub-
lished information and unpublished re-
cords. The biogeography shows that M.
cranium is almost completely confined to
the shelves surrounding the North Atlantic
and the Norwegian-Greenland Sea. When
this distribution pattem is compared with
published information on autecology and
possible limiting environmental factors, the
conclusion reached is that there is substan-
tial evidence for the pattern being a func-
tion of dispersal by the Gulf Stream (cf.
Helmcke, 1939b) and its continuations, i.e.
the North Atlantic Current, the Norwegian
Current and the North Cape Current. Thus
the stratigraphical occurrence of M. crani-
um in Late Weichselian-Holocene sedi-
ments on the Norwegian shelf maý be used
as an important marker for the presence of
Atlantic Water and the final intrusion of At-
lantic Water masses. In connection with
this study, the distribution of M. cranium on
the Faroe platform was mapped (Thomsen,
1989) based on Wesenberg-Lund (1940,
1941) and O.S. Tendal (pers. comm., Nør-
revang etal., 1994). It confirmed the affini-
ty of the species to the Atlantic Water (also
demonstrated in the present paper). Curry
and Endo (1991) later also found a palae-
oceanographic connection when studying
the distribution of the two terebratulinids in
the North Atlantic. They concluded that T.
retusa has its main distribution in the east-
em North Atlantic and T. septentrionalis in
the western North Atlantic, with the excep-
tion of a supposed relict occurrence of T.
retusa off Finnmark, northern Norway.
However, Thomsen and Brattegard (1997)
recorded T. septentrionalis from Hordaland
northwards into the Barents Sea.
Recently, Pakhnevich (1997) has studied
the size and age characteristics of Macan-
drevia cranium based on two trawl sam-
ples, one of which was recovered by the
R/V ”Sevastopol” south-west off the
Faroes in 1959.
The BIOFAR programme
The BIOFAR programme (Investigations
on the marine benthic fauna of the Faroe Is-
lands) is a Nordic research programme
(Nørrevang et al., 1994). The aim of the
programme is to study the marine benthic