Geoscience Reference
In-Depth Information
There are essentially two, somewhat
different, eurypterid faunas in the Bertie
Group. The Fiddlers Green Formation is
best developed in the eastern part of the
outcrop, especially at the well-known
Passage Gulf locality. The Williamsville
Formation is better developed in the
western part of the outcrop, around
Williamsville itself (near Buffalo, 71 ) and
in quarries in Ontario, such as the
Ridgemount complex ( 72 ). However, the
horizon and locality from which
specimens came from were not always
recorded. Early in the history of studies on
the eurypterids of New York, it was
apparent that there were two forms of
Eurypterus which formed the bulk of
specimens collected: Eurypterus remipes
( 73 ) and E. lacustris . They can be
distinguished by size and the width-length
ratio of the carapace: E. lacustris is
supposedly larger and slimmer than
E. remipes .
In their monumental monograph on
the eurypterids of New York, Clarke and
Ruedemann (1912) distinguished the
two species and noted that E. remipes
occurs in the Herkimer County localities
of the Bertie Waterlime whereas
E. lacustris is found in the Erie district
(see also Ruedemann, 1925). Kjellesvig-
Waering (1958) considered that the
differences between these species and the
European E. tetragonophthalmus were so
slight as to be of mere subspecific status.
Thus he recognized a single species
Eurypterus remipes with subspecies
remipes , lacustris , d tetragono-
phthalmus . (Kjellesvig-Waering, 1958,
p. 1137). Andrews et al . (1974), in the
first statistical morphometric study of
eurypterids, agreed with the subspecific
status of the European and American
E. remipes . However, Størmer (1973)
considered the paddle shape to be
sufficiently different to warrant
separation of the European species into a
different genus, Baltoeurypterus .
Kjellesvig-Waering later concurred with
Størmer's view and, indeed, described a
new species of Baltoeurypterus
(Kjellesvig-Waering, 1999). It should be
pointed out that the males of E.
tetragonophthalmus have a distinctive
scimitar lobe on appendage II, which is
unknown in any other species of
Eurypterus (Størmer and Kjellesvig-
Waering, 1969; Selden, 1981; Braddy and
Dunlop, 1997).
More recent morphometric work by
Tollerton (1992) indicated that while
E. lacustris and E. remipes could be told
apart by carapace shape at large sizes, they
were not distinguishable as juveniles. He
surmised that E. lacustris (which occurs in
the higher Williamsville strata) could have
71
71 Type locality of the Williamsville
Formation adjacent to the old mill at
Williamsville, New York, and Sam Ciurca,
prolific collector of Bertie fossils.
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