Eurypterids
Specimen of the Month
Samuel J. Ciurca, Jr., Rochester, New York           by Eurypterids.net
A LITTLE OF THIS, A LITTLE OF THAT!
Waeringopterus, Erieopterus, Paracarcinosoma, Eurypterus
MAY 2009
Counter
COMMENTARY:
Will we ever know the true habitat of the eurypterids? Through hundreds of feet of strata, from the base of the Vernon
Formation (Salina Group) up into the Early Devonian limestones and dolostones of New York and Ontario, Canada,
distinct eurypterid faunas punctuate the sequence. One fauna occurs and is replaced in the vertical section by
another very distinct fauna and on right into the Early Devonian. Even with all of the eurypterid faunas now known,
there are still more to be discovered within this great geographic expanse. Why?
When I found my first eurypterid, within a glacial erratic, only a few years out of high school - who (including me) would
have ever thought that that single event would lead to over forty years of constructing an enormous collection of
these extinct creatures from known occurrences and newly discovered horizons. The thousands of hours I spent
amassing the collection are history. I did not simply collect objects (like the beer cans I started to collect once, in my
early years I might add), I 'collected' field experience, an increasing knowledge of strata and the sediments comprising
them. Stratigraphy became at least as interesting as finding another fossil and many of the rock layers I encountered
exhibited unusual lithologies - most, little understood. There are many eurypterids I would not have found, and new
horizons I would not have recognized if I had neglected stratigraphy.
I'm not sure about other parts of the world, especially Siluro-Devonian sections, but 'our' eurypterids occur within an
evaporite sequence with commercial deposits of halite and gypsum and at least relict structures of salts when the
actual deposits are not present. Many of the eurypterid-bearing waterlimes of the Salina and Bertie Groups contain
fantastic salt hopper structures (perhaps a good topic for June 2009) and other manifestations of evaporite
sedimentary structures. The structures have been found on eurypterid integument itself and on what are interpreted
to be 'algal' clasts ripped up from microbialite mats often found in eurypterid beds.
FOR AN EARLY INTERPRETATION
OF THE PALEOENVIRONMENT OF
EURYPTERIDS AND ASSOCIATED
FAUNAS AND FLORAS, CHECK OUT:
The Habitat of the Eurypterida
by Marjorie O'Connell, published in
1916, Buffalo Society of Natural
Sciences (Buffalo, New York) ...
Waeringopterus, named
after a good friend (Erik N.
Kjellesvig-Waering) who
published many papers on
eurypterids and scorpions
(do a Google search). This
wonderful eurypterid is
mostly known from trans-
itional beds in the lower
Syracuse Formation (Salina
Group) of New York and
Ontario, Canada. It is a very
common form, but rarely
encountered due to poor
exposures of the dolostones
that contain them.
Biostratigraphically, this is an
important genus in the
absence of typical marine
invertebrates. From eastern
New York,
Waeringopterus
occurs westward into the
Niagara Peninsula of Ontario,
Canada.
The specimen shown here is
a negative - the bulging eyes
are an illusion, welcome
photographically.
BELOW:
Paracarcinosoma scorpionis from the Williamsville Waterlime near Clifton Springs, New York
Scorpionlike, Paracarcinosoma
bears a curved telson that may
have borne a poison gland. The
tubular postabdomen was able
to coil itself upward and forward
like modern scorpions. It is one
of the many bizarre kinds of
eurypterids known from Silurian
rocks around the world. It is rare
to find specimens, but a few
nearly complete specimens are
known, housed in museums.
BELOW:
Eurypterus remipes from the upper Fiddlers Green Formation at Passage Gulf, N.Y.
Eurypterus remipes DeKay from the Phelps
Waterlime, Fiddlers Green Formation of the Late
Silurian Bertie Group at Passage Gulf, eastern
New York. Most of the anterior appendages are
preserved in this specimen.
E. remipes is found
over a great geographical area from Deck in
eastern New York westward to Hagersville,
Ontario, Canada.
Erieopterus sp.
Carapace with small, 'beany'
eyes.
Erieopterus appears
abruptly in the section at the
Silurian-Devonian boundary in
New York and Ontario, Canada.
It is an extremely common form,
but exposures of the strata that
contain the eurypterid horizons
are difficult to collect from due to
their hard or resistant nature.
Nevertheless, specimens are
now known from many distinct
horizons within the Olney Lime-
stone, and the Chrysler and
Thacher Formations. In western
New York, the Honeoye Falls
Fm., and in Canada the
Clanbrassil Fm. also yield this
genus.
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